Participants, Title of Talks and Poster Contributions


  1. Abraão Jessé Capistrano de Souza (Fundação Universidade Federal do Tocantins (UFT), Palmas, Brazil)
    • Tittle of Talk (STARS2011): On the Geometrical Effect of Dark Matter

      Abraão Jessé Capistrano de Souza, Pedro Ivo Odon and Luis A. Cabral

      Abstract: We study the effect of the extrinsic curvature on the rotation curves within the context of brane-world, in a 5-d bulk with constant curvature. The covariant equations of motion for the brane-world are applied to determine the modified Newtonian potential approximation and the velocity curve. Two cases are examined: first, we consider a galaxy predominantly dominated by a spherical mass distribution leading to a small correction to the usual Newtonian potential. Secondly, we consider a static disk galaxy which is composed only by the ordinary visible matter. Using the Weyl static metric as a model, we find that the velocity curve is given by the square root of a small power of the distance to the galactic center, representing the brane-world warp caused by the disk edge.

  2. Alain Blanchard (Institut de Recherche en Astrophysiqué et Planetology (IRAP), Toulouse, France)
    • Tittle of Talk (STARS2011): The Cluster Conundrum

      Alain Blanchard

      Abstract: The abundance of clusters and its variation with redshift has been proposed as a powerful cosmological test. Recent studies have shown that it may be used to bring critical information on modified theory of gravity. However, existing data on x-ray clusters abundance have been analyzed by different teams and lead to contradictory results. I will discuss our latest analysis of this question and show that indeed the abundance of x-ray clusters seems to be at odd with expectation within a standard concordance model.Solutions to this problem will also be proposed.

  3. Alain Ulacia Rey (Instituto de Cibernética, Matemática y Física (ICIMAF), La Habana, Cuba)
    • Title of Talk (STARS2011): Contributions of Riemann invariants to the Entropy of Extremal Black Holes

      Alain Ulacia Rey

      Abstract: We use the entropy function formalism introduced by A. Sen to obtain the entropy of AdS2 X Sd-2 extremal and static black holes(BH) in four and five dimensions, with higher derivative terms of a general type. Starting from a generalized Einstein-Maxwell action with nonzero cosmological constant, we examine all possible scalar invariants that can be formed from the complete set of Riemann invariants (up to order 10 in derivatives). The resulting entropies show the deviation from the well know Bekenstein-Hawking area law S=A/(4G) for Einstein's gravity up to second order derivatives.

    • Title of Talk (SMFNS2011): Perturbed Bianchi-I Space-time with Magnetic Sources

      Alain Ulacia Rey

      Abstract: In this work we calculate the complete set of cinematic variables for a perturbed Bianchi-I space-time. In this order, we used these general results on the Raychaudihuri equation that physically could shed light for several physical conditions of collapse, on a perturbed background.

  4. Alejandro Cabo Montes de Oca (Instituto de Cibernética, Matemática y Física (ICIMAF), La Habana, Cuba)
    • Title of Talk (STARS2011): Dilaton Stabilization by Massive Fermions

      Alejandro Cabo, Robert Brandenberger, Matts Roos and Encieh Erfani

      Abstract: The Dilaton stabilization problem is investigated when the effective potential for this field is generated by the existence of a massive fermion. The previously evaluated two loop correction for this quantity indicates that the Dilaton field tends to be fixed at a high value close to the Planck scale, in accord with the needs for predicting Einstein gravity from string theory. Moreover, the mass of the Dilaton is evaluated to be close to the Planck mass, which assures the absence of Dilaton scalar signals in modern cosmological observations. These properties arise when the fermion mass is chosen to be either at a lower bound corresponding to the top quark mass, or alternatively, at a very much higher value assumed to be in the grand unification energy range. The renormalization scale μ is chosen to be given by the Z particle mass. We also consider the case when μ is a dynamical parameter fixed by minimization of the effective potential. The results rest on the basic assumption that the higher three or more loop calculations do not drastically affect the two loop potential. Higher loop sample calculations are expected to be considered elsewhere in order to give full ground to the conclusions.

  5. Alexandre Mesquita (Universidade de Caxias do Sul (UCS), Caxias do Sul, Brazil)
    • Title of Poster Contribution (STARS2011) (proposal): The Role of Isovector Mesons and Antikaon Condensates in Pulsars

      Alexandre Mesquita, Moisés Razeira, Francisco Fernández, César A. Zen Vasconcellos and Dimiter Hadijimichef

      Abstract: In this contribution we study the effects in the structure of pulsars of isovector mesons and antikaons degrees of freedom. For this task we consider a phase transition of nuclear matter to nuclear matter containing a condensate of antikaons using an effective model with derivative couplings. In our formalism, nucleons interact through the exchange of sigma, omega, rho, and delta meson fields in the presence of a background of electrons to accomplish electric charge neutrality and beta equilibrium. The phase transition to the antikaons condensate was implemented through the Gibbs conditions combined with the mean-field approximation, giving rise to a mixed phase of coexistence between nuclear matter and the condensed of antikaons. Pulsar rotation, in our approach, is implemented considering interior solutions for the dragging frequency. Our results confirm that isovector mesons operate to restore the isospin symmetry of nuclear matter and to reduce the value of the effective mass of baryons, a result that is independent of the depth of the optical potential for antikaons. Also, as expected, it was found that increasing the depth of the optical potential favors the increase of antikaons population. Moreover, assuming neutrino-free matter, we observe a rapid decrease of the electron chemical potential produced by the gradual substitution of electrons by kaons to accomplish electric charge neutrality. The effects of rotation in the equation of state are synthesized in this contribution.

    • Title of Poster Contribution (STARS2011) (proposal): Glueball-Dilaton as an Alternative to Dark Matter in Neutron Stars

      Alexandre Mesquita, José Eduardo Costa, César A. Zen Vasconcellos, Moisés Razeira, Francisco Fernández and Dimiter Hadjimichef

      Abstract: We study cold nuclear matter based on a mean field description of baryons bound by the exchange of scalar-isoscalar, vector-isoscalar, scalar-isovector and vector-isovector meson fields as well as the glueball field. For this task, we use an extended version of the effective model with derivative couplings with genuine many-body forces simulated by nonlinear self-couplings involving meson-meson interaction terms and the glueball fields. In our approach, the realization of the broken scale invariance of quantum chromodynamics is achieved through the introduction of the dilaton field. The effective model with dilatons is then applied to the description of neutron stars.

    • Title of Poster Contribution (SMFNS2011) (proposal): Relativistic URCA Process in Neutron Star with Antikaons

      Alexandre Mesquita, Moises Razeira, Francisco Fernández, Cesar Z. Vasconcellos and Dimiter Hadjimichef

      Abstract: Under the framework of a relativistic mean field description of nuclear matter with baryons bound by the exchange of scalar-isoscalar, vector-isoscalar, scalar-isovector and vector-isovector meson fields as well as antikaons degrees of freedom, we study the cooling process of neutron stars and pulsars.

  6. Andres Escala (Universidad de Chile, Santiago, Chile)
    • Title of Talk (STARS2011): Gas induced Mergers of Massive Black Holes

      Andres Escala

      Abstract: Using high-resolution SPH numerical simulations, we investigate the effects of gas on the inspiral and merger of a massive black hole binary. This study is motivated by both observational and theoretical work that indicate the presence of large amounts of gas in the central regions of merging galaxies. I will focus on the role of tidal (ellipsoidal) torques in the MBHs dynamics. In particular, I will discuss under which disk models the formation of a circumbinary gap wil l be prevented and the tidal torques will efficiently extract angular momentum from the MBH binary, and under which models a stable circumbinary gap will be opened. The final coalescence of the black holes leads to gravitational radiation emission that would be detectable up to high redshift by LISA, and will provide spectacular insights into the formation and co-evolution of galaxies and central black holes.

  7. Anna Maria Freire Endler (Centro Brasileiro de Pesquisas Físicas (CBPF), Rio de Janeiro, Brazil)
    • Title of Talk (STARS2011): About the Unimaginably Small and the Incredibly Large

      Anna Maria Freire Endler

      Abstract: We are the first generation of human beings to glimpse the full run of cosmic history, from the universe’s origin in the Big Bang to the silent flight of galaxies through the intergalactic space. We are the first to make the connection between the inner space of elementary particles and the outer space, about planets, stars and galaxies. We can say, we can now better understand about the entire universe. The detailed information on sub-nuclear phenomena helps very much to understand the evolution of the Universe, formation of Stars and Galaxies. This talk has the intention to show how it can be enjoyable the inner space and outer space adventure and to see how they are connected. In the inner space, the elementary particles and the different fundamental forces in the nature are described and the attempts for a great unification mentioned. In the outer space, it is mentioned the evolution of the universe with the creation of galaxies and stars with the different kinds of their deaths, resulting the black holes, neutron stars and white dwarfs.

  8. Aurora Pérez Martínez (Instituto de Cibernética, Matemática y Física (ICIMAF), La Habana, Cuba)
    • Title of Talk (SMFNS2011): Compact Stars and Magnetized Color Flavor Locked State

      Aurora Pérez Martínez, R. Gonzalez and Daryel Manreza Paret

      Abstract: The stability of the color flavor locked phase in the presence of a strong magnetic field is investigated within the phenomenological MIT bag model, taking into account the variation of the strange quark mass, the baryon density, the magnetic field, as well as the bag and gap parameters. It is found that the minimum value of the energy per baryon in a color flavor locked state at vanishing pressure is lower than the corresponding one for unpaired magnetized strange quark matter and, as the magnetic field increases, the energy per baryon decreases. This implies that magnetized color flavor locked matter is more stable and could become the ground state inside neutron stars. The mass-radius relation for such stars is also studied.

    • Title of Poster Contribution (SMFNS2011) (proposal): The Role of Isovector Mesons, Antikaon Condensates and Strong Magnetic Fields in Pulsars

      Aurora Pérez Martínez, Hugo Pérez Rojas, Daryel Manreza Paret, Rosana Oliveira Gomes, Alexandre Mesquita, Moisés Razeira and César Zen Vasconcellos

      Abstract: In this contribution we study the effects of isovector mesons, antikaon condensates and strong magnetic fields in the structure of pulsars. We consider, for this task, a phase transition to nuclear matter containing an antikaon condensate using an effective model with derivative couplings. Nucleon fields interact in this formalism through the exchange of sigma, omega, rho, and delta meson fields in the presence of a background of electrons to accomplish electric charge neutrality and beta equilibrium. As conventionally assumed, Landau diamagnetism and Pauli paramagnetism interaction terms are properly introduced in our lagrangian formalism in order to consider the interaction of charged and neutral baryons with the magnetic field. We then seek for stationary-state solutions of the modified Dirac equation in the presence of strong magnetic fields. In order to implement the phase transition we use the Gibbs conditions combined with the mean-field approximation, giving rise to a mixed phase of coexistence between nuclear matter and the condensed of antikaons. Pulsar rotation, in our approach, is implemented considering interior solutions for the dragging frequency. Then we analyze the consequences of our approach on already known properties of nuclear matter, ie, the compression modulus, the effective nucleon mass and the maximum neutron star mass predicted by integrating the TOV equations as well as on rotation properties of the pulsar.

  9. Carola Dobrigkeit (Universidade Estadual de Campinas (UNICAMP), Campinas, Brazil)
    • Title of Talk (STARS2011): Recent results from the Pierre Auger Observatory

      Carola Dobrigkeit (for the Pierre Auger Collaboration)

      Abstract: The Pierre Auger Observatory in Argentina is the largest cosmic ray detector array ever built. Its main goal is to study cosmic rays above 1 ~ 10 EeV. Although the construction of its baseline design was completed in mid 2008, the Observatory is taking data continuously since January 2004. The main results obtained with the Pierre Auger Observatory will be presented, with emphasis on the energy spectrum, composition and arrival directions of the ultra-high energy cosmic rays. Features observed in the energy spectrum will be discussed. Results about the composition obtained from systematic studies of the average depth of shower maximum and its fluctuations will be reviewed. Recent results of studies of correlations with nearby extragalactic objects, including evidences of an excess in the direction of Centaurus A, will be presented.

  10. César Augusto Zen Vasconcellos (Universidade Federal do Rio Grande do Sul (UFRGS), Porto Alegre, Brazil)
  11. César A. Terrero Escalante (Universidad de Colima, Colima, Mexico)
    • Title of Talk (STARS2011): Out of this World Darkness

      César A. Terrero Escalante, Leopoldo A. Pando Zayas and Norma Quiróz

      Abstract: A cosmological model is developed without exotic, unobservable matter components in the effective 4-dimensional energy-stress tensor. The model is based on the scenario of the so called mirage cosmology. The accelerated expansions assumed to be caused by the inflaton or the dark energy are consequences of the motion of our universe (a D3-brane) in a 10-dimensional type IIB supergravity background. In turn, the dark matter may come from a hidden sector which couples to the matter in the brane-universe only via higher-dimension operators.

  12. Christian Motch (CNRS Observatoire Astronomique, Université de Strasbourg, Strasbourg, France)
    • Title of Talk (SMFNS2011): X-ray in Isolated Neutron Stars: magnetic fields and evolutionary status

      Christian Motch

      Abstract: The seven isolated neutron stars discovered in the ROSAT all-sky survey represent the tip of the iceberg of a population which could be as numerous as that of the classical radio pulsars. Their low magnetospheric activity allows us to observe their surface in a rather clean manner. This has made possible the discovery of cyclotron absorption lines indicating strong magnetic fields with values consistent with those derived from spin-down studies. We will review the overall observational properties of these neutron stars and discuss their possible evolutionary links to other classes of isolated neutron stars.

  13. Daryel Manreza Paret (Instituto de Cibernética, Matemática y Física (ICIMAF), La Habana, Cuba)
    • Title of Talk (SMFNS2011): Astrophysical Properties of Magnetized Quark Stars

      Daryel Manreza Paret and Aurora Pérez Martínez

      Abstract: This work aims to study how amending certain astrophysical observable of quark stars due to presence of magnetic field. We will work using the phenomenological MIT Bag model. The stability of the Magnetized Strange Quark Matter (MSQM) is studied taking into account the variation of parameters from the model: s quark mass, baryonic density, magnetic field and the Bag parameter. Results obtained were compared with those of magnetized normal quark matter (only u and d quarks in beta equilibrium) as well as the Strange Quark Matter (SQM). It is found that the energy per baryon decreases with the increasing magnetic field which implies that the MSQM is more stable than SQM. The Equations of State previously obtained are used to obtain stable configurations of magnetized strange stars checking that the magnetic field helps to reduce Mass-Radius (M-R) ratio of the star.

  14. Debora Péres Menezes (Universidade Federal de Santa Catarina (UFSC), Florianópolis, Brazil)
    • Title of Talk (STARS2011): Neutrino Opacities and the Pasta Phase Structure

      Debora Péres Menezes and M.D. Alloy

      Abstract: The diffusion coefficients, related to the neutrino opacities, are calculated considering the formation of nuclear pasta and homogeneous matter at low densities. The obtained mean free paths are significantly altered by the presence of nuclear pasta in stellar matter when compared with the results obtained with homogeneous matter. These differences in neutrino opacities will influence the Kelvin-Helmholtz phase of protoneutron stars and consequently the results of their evolution.

    • Title of Talk (SMFNS2011): Finite Temperature Matter Subject to Strong Magnetic Fields

      Debora Péres Menezes, Sidney S. Avancini and C. Providencia

      Abstract: We know that the energy per baryon of magnetized quark matter becomes more bound than nuclear matter made of iron nuclei, for a magnetic field around 2 X 1019 G. We use the mean field approximation to investigate quark matter described by the su(3) Nambu--Jona-Lasinio model subject to a strong magnetic field both at zero and finite temperature.

  15. Donald B. Melrose (School of Physic, The University of Sydney, Australia)
    • Title of Talk (STARS2011): Magnetic Explosions, with Application to Magnetar Outbursts and to Solar Flares

      Don Melrose

      Abstract: Magnetars are slowly rotating neutron stars with much stronger magnetic fields than in normal pulsars. Magnetar outbursts involve explosive release of magnetic energy. Two more familiar examples of explosive magnetic energy release are in solar flares and magnetospheric substorms. In this talk I will concentrate on the similarities between these phenomena, arguing that they are three examples of "magnetic explosions". Magnetic explosions need to be understood on at least three different scales: a global scale, that determines the energetics; a macro scale that involves separate energy-release and particle-acceleration regions and propagation between them; and a micro scale on which collisionless dissipation occurs.

    • Title of Talk (SMFNS2011): Dispersion in a Spin-dependent Magnetized Relativistic Quantum Electron Gas

      Don Melrosse

      Abstract: An electron gas in a magnetic field can be magnetised due to a preferred alignment of the spins. The response of such an electron gas to an electromagnetic perturbation leads to a spin-dependent contribution to the dielectric tensor. The properties of the wave modes of a cold spin-dependent electron gas are derived using a quasi-classical theory based on the BMT equation. The spin-dependent result is calculated exactly using Dirac's equation for a magnetized electron. The approximations that need to be made to reduce the general result to the quasi-classical case are discussed.

  16. Eduardo Guendelman (Ben Gurion University, Negev, Israel)
    • Title of Talk (STARS2011): Bags and Confinement Governed by S.S.B. of Scale Invariance

      Eduardo Guendelman

      Abstract: A general coordinate invariant theory is constructed where confinement of gauge fields and gauge dynamics in general is governed by the spontaneous symmetry breaking (s.s.b.) of scale invariance. The model uses two measures of integration in the action, the standard (√-g), where g is the determinant of the metric and another measure, Phi, independent of the metric. To implement scale invariance (S.I.), a dilaton field is introduced. Using the first order formalism, curvature (Phi.R and (√-g) R2)) terms, gauge field term and dilaton kinetic terms are introduced in a conformally invariant way. Exponential potentials for the dilaton break down (softly) the conformal invariance down to global scale invariance, which also suffers s.s.b. after integrating the equations of motion. The model has a well-defined flat space limit. As a result of the s.s.b. of scale invariance phases with different vacuum energy density appear. Inside the bags, that is in the regions of larger vacuum energy density, the gauge dynamics is normal, that is non-confining, while for the region of smaller vacuum energy density, the gauge field dynamics is confining. Likewise, the dynamics of scalars, like would be Goldstone bosons, is suppressed inside the bags.

    • Title of Talk (SMFNS2011): Cosmic Analogues of the Stern-Gerlach Experiment and the Detection of Light Bosons

      Author: Eduardo Guendelman

      Abstract: We show that, by studying the arrival times of radio pulses from highly-magnetized pulsars, it may be possible to detect light spin-0 bosons (such as axions and axion-like particles) with a much greater sensitivity, over a broad particle mass range than is currently reachable by terrestrial experiments and indirect astrophysical bounds. In particular, we study the effect of splitting of photon-boson beams under intense magnetic field gradients in magnetars and show that radio pulses (at meter wavelengths) may be split and shift by a discernible phase down to a photon-boson coupling constant of g ~ 1e-14 [1/GeV]; i.e., about four orders of magnitude lower than current upper limits on g. The effect increases linearly with photon wavelength with split pulses having equal fluxes and similar polarizations. These properties make the identification of beam-splitting and beam deflection effects straightforward with currently available data. Better understanding of radio emission from magnetars is, however, required to confidently exclude regions in the parameter space when such effects are not observed.

  17. Elizabeth Rodrigues Querts (Instituto de Cibernética, Matemática y Física (ICIMAF), La Habana, Cuba)
    • Title of Talk (SMFNS2011): About QED Magnetized Vacuum Decay in Large Fields

      Elizabeth Rodrigues Querts and Hugo Pérez Rojas

    • Title of Poster Contribution (SMFNS2011): Self-magnetization in Electroweak Vacuum and in Very Dense Systems

      Elizabeth Rodriguez Querts and H. Perez Rojas

      Abstract: For charged vector bosons (W bosons) of mass MW , their vacuum energy density diverges for some B=Bc where Bc is a critical value, leading to a instability. The vacuum magnetization also diverges for B → Bc which suggests that if the magnetic field is large enough, it can be self-consistently maintained, and this mechanism actually prevents B from reaching the critical unstable value Bc. For neutral vector bosons bearing an anomalous magnetic moment, the instability of the ground state is produced also for some critical field. We discuss these models in connection to the case of radiation in equilibrium at high temperature (T~ mc2) coexisting with hot magnetized electron-positron pairs. Their bosonization would lead to physical conditions for the applicability of the previous neutral bosons model to describe a possible self-magnetization of the system.

  18. Eloy Ayón Beato (Centro de Investigación y de Estudios Avanzados del Instituto Politécnico Nacional (CINVESTAV), Ciudad de México, México)
    • Title of Talk (STARS2011): Analytic Lifshitz Black Holes in Higher Dimensions

      Eloy Ayón Beato

      Abstract: We generalize the four-dimensional R2-corrected z=3/2 Lifshitz black hole to a two-parameter family of black hole solutions with asymptotic Lifshitz symmetry for any dynamical exponent z and for any dimension D. For a particular relation between the parameters, we find the first example of an extremal Lifshitz black hole. An asymptotically Lifshitz black hole with a logarithmic decay is also exhibited for a specific critical exponent depending on the dimension. Additionally, we show how to generalize the two-parameter family of black holes to include other horizont topologies. We extend this analysis to the more general quadratic curvature corrections for which we present three new families of higher-dimensional D≥5 analytic Lifshitz black holes for generic z. One of these higher-dimensional families contains as critical limits the z=3 three-dimensional Lifshitz black hole and a new z=6 four-dimensional black hole. The variety of analytic solutions presented here encourages exploring these gravity models within the context of non-relativistic holographic correspondence.

    • Title of Talk (SMFNS2011): Nonlinearly Charged Regular Black Holes

      Eloy Ayón Beato

      Abstract: It is clear now that black holes are not necessarily singular. We review some of the aspects that led to this conclusion, allowing the discovery of the first regular exact black hole solutions by means of nonlinearly charged sources.

  19. Ernesto Kemp (Universidade Estadual de Campinas (UNICAMP), Campinas, Brazil)
    • Title of Talk (STARS2011): Extracting Limits for the Diffuse Non-Electron Neutrino Flux from SNO Data

      Bruno Miguez, Orlando L.G. Peres, Ernesto Kemp

      Abstract: There is a predicted diffuse neutrino flux originated by all supernova already exploded in the past. This flux is weighted by stellar formation and supernovae occurrence rates. The expected energy spectrum of these neutrinos differs from those from recent supernova mainly by their energy “redshift” due the expansion of the universe. Thus, despite the fact that one single supernova is a transient state; their cumulative effect produces a steady flux of diffuse neutrinos everywhere in universe. These neutrinos have never been observed before. Only upper limits on their fluxes have been reported by the collaborations operating neutrino telescopes. The SNO experiment published an analysis where the total flux of diffuse electron neutrinos has an upper limit of φe ≤ 61-93 cm-2.s-1, depending on a specific supernova model. At the present, the best limit for the diffuse flux of non-electron neutrinos is φx ≤ 10³ cm-2.s-1, resulted from an analysis of the Super-Kamiokande data. In this work we have extended the SNO analysis including the elastic scattering on electrons via neutral current interactions to extract information on diffuse flux of the non-electron neutrino flavors (i.e. muon and tau neutrinos). Our analysis yield as limits to non-electron neutrinos flux above to 21 MeV φx ≤ (2.1-17) 10³ cm-2.s-1 and φx ≤ (6.5-23) 10³ cm-2.s-1 as limit to non-electron antineutrinos flux.

    • Title of Poster Contribution (STARS2011): Estimating the Distances of Stellar Collapses in the Galaxy Analyzing the Energy Spectrum of Neutrino Bursts

      Ernesto Kemp, Bruno Miguez and Walter Fulgione

      Abstract: There is a rather good consensus both in theoretical and experimental basis, coming from observations of the SN1987A, that a supernova explosion is preceded by a huge flux of neutrinos from the three flavors and their antiparticles. In principle, large neutrino telescopes are able disentangle the neutrino burst signal from the background fluctuations. If a minimum number of collected events is enough to build the energy spectrum, further analysis can be carried out to get spectrum parameters providing astrophysical information from the innermost regions of the collapsed object. In this work we show some preliminary results about the method we are proposing to determine the distance from the collapsing star, using only the information of the spectral shape from expected antinu-e events on neutrino telescopes, such as the LVD at the LNGS - Italy, and assumptions on the total binding energy of the stellar core released in the collapsing process. In this preliminary phase we focus the discussion on the errors of the method related to the theoretical uncertainties concerning the energy released in the formation of the compact object resulting from the collapse.

    • Title of Talk (SMFNS2011): Wavelets Applied to the Detection of Point Sources of UHECRs

      Rafael Alves Batista, Ernesto Kemp, Bruno Daniel and Rogério M. de Almeida

      Abstract: In this work we analyze the effect of smoothing sky maps containing arrival directions of cosmic rays with a Gaussian kernel and also kernels of the Mexican hat wavelets of orders 1, 2 and 3. The analysis were performed by calculating the amplification of the signal-to-noise ratio for several background patterns (noise) and different number of events coming from a simulated source (signal). In the simulations we have considered different scenarios of UHECRs detection, for instance an ideal detector capable of observing the full sky with equal probability in all directions as well as a detector with limited acceptance law (a standard formulation sin(theta)*cos(theta) ). The geographical position of our virtual detector was chose to optimize its exposure to the sky. The results are discussed in terms of signal/noise ratio achieved for different angular scales and the effects of the limited acceptance of the detector in comparison of a homogeneous coverage of the sky.

  20. Ernesto López Fune (Instituto de Cibernética, Matemática y Física (ICIMAF), La Habana, Cuba)
    • Title of Talk (SMFNS2011): Magnetized Strangelets at Finite Temperature

      Ernesto López Fune

      Abstract: The main properties of magnetized strangelets such as the energy per baryon, radii and electric charge are studied. Temperature effects are also taken into account, in order to study their stability compared to the 56Fe isotope and non-magnetized strangelets using the Liquid Drop Model. Massive quarks are considered with the aim to have a more realistic description for strangelets in the astrophysical context, and also the environment of heavy ion colliders, playing an important role in the thermodynamical magnitudes of the quark gas. The presence of a magnetic field, tends to stabilize more strangelets, even when temperature effects are taken into account. MSQM strangelets in a paired superconductor phase, are also studied, where we also checked that they are more stable than ordinary MSQM strangelets for a typical gap of 100 MeV.

  21. Felix Mirabel (Commissariat a l'Energie Atomique (CEA), France and CONICET, Argentina)
    • Title of Talk (STARS2011): Astrophysical Black Holes and their Role in Cosmic Evolution

      Felix Mirabel

      Abstract: I will review the present status of the observations of astrophysical black holes (stellar and supermassive), with particular emphasis on the relativistic phenomena.

    • Title of Talk (SMFNS2011): The Role of Black Holes in Cosmic Evolution

      Felix Mirabel

      Abstract: I will show that feedback in the form of high energy radiation, jets and massive winds from accreting black holes played important roles in the re-ionization epoch of the universe, as well as in the formation of galaxies of all mass scales.

  22. Fernando Silveira Navarra (Universidade de São Paulo (USP), São Paulo, Brazil)
    • Title of Talk (STARS2011): Gluon Condensates in Dense Stars

      Fernando S. Navarra and David A. Fogaça

      Abstract: Quark gluon plasma with high chemical potential and almost zero temperature may exist in the core of compact stars. Most likely it is a strongly interacting system. The strong interactions may be partly due to non-perturbative effects, which survive after the deconfinement transition and which can be related with the non-vanishing gluon condensates in the sQGP. In this work, starting from the QCD Lagrangian we perform a gluon field decomposition in low ("soft") and high ("hard") momentum components, we make a mean field approximation for the hard gluons and take the matrix elements of the soft gluon fields in the plasma. The latter are related to the condensates of dimension two and four. With these approximations we derive an analytical expression for the equation of state, which is compared to the MIT bag model one. The effect of the condensates is to soften the equation of state whereas the hard gluons significantly increase the energy density and the pressure.

  23. Genly Leon Torres (Universidade Central Marta Abreu de Las Villas, Cuba) -
    • Title of Talk (STARS2011): Phase Space of Anisotropic Rn Cosmologies

      Genly Leon Torres and Emmanuel N Saridakis

      Abstract: We construct general anisotropic cosmological scenarios governed by an f(R) gravitational sector. Focusing then on some specific geometry in the case of Rn-gravity, and modeling the matter content as a perfect fluid, we perform a detailed phase-space analysis. We analyze the possibility of accelerating expansion at late times, and additionally, we determine conditions for the parameter n for the existence of phantom behavior, contracting solutions as well as of cyclic cosmology. Furthermore, we analyze if the universe evolves torwards the future isotropization. This result has been achieved by us for Kantowsky-Sachs geometries without relying on a cosmic no-hair theorem. Our results indicate that anisotropic geometries in modified gravitational frameworks present radically different cosmological behaviors compared to the simple isotropic scenarios.

  24. German Lugones (Universidade Federal do ABC (UFABC), Santo André, Brazil)
    • Title of Talk (STARS2011): Quark Matter Deconfinement in Compact Stars

      German Lugones

      Abstract: In this work we present new results on the deconfinement transition in old neutron stars and in protoneutron stars. We impose color and flavor conservation during the transition in such a way that just deconfined quark matter is transitorily out of equilibrium with respect to weak interactions. The hadronic phase is described through a relativistic mean field model and quark matter through the Nambu-Jona-Lasinio model and the MIT Bag model. We study the effect of color superconductivity and neutrino trapping on the critical density for deconfinement. We explore some astrophysical consequences of the results, in particular, the possible generation of short gamma ray bursts.

  25. Hugo Celso Pérez Rojas (Instituto de Cibernética, Matemática y Física (ICIMAF), La Habana, Cuba)
    • Title of Talk (SMFNS2011): Photon Redshift in a Magnetic Field

      Hugo Celso Pérez Rojas, Elizabeth Rodriguez Querts and José Helayel Netto

      Abstract: Previous results concerning the arising a tiny photon anomalous paramagnetic moment are also interpreted as a red-shift in analogy to the gravitational known effect. It is due to the photon interaction with the magnetized virtual electron-positron background which withdraws transverse momentum from photons and is polarization-dependent. The photon frequency red-shift implies a change in time and a clock would go faster for increasing magnetic field intensity

    • Title of Poster Contribution (SMFNS2011) (proposal): Naturalness and Magnetic Constraining of the Equation of State of the Double Pulsar J07373039

      Hugo Pérez Rojas, Aurora Pérez Martínez, Daryel Manreza Paret, Rosana Oliveira Gomes, Alexandre Mesquita, Moisés Razeira and César Zen Vasconcellos

      Abstract: We investigate the role of naturalness and magnetization in an extended version of the parametric coupling effective model which includes the whole fundamental baryon octet and genuine many-body forces simulated by nonlinear self-couplings and meson-meson interaction terms involving scalar-isoscalar, vector-isoscalar, vector-isovector and scalar-isovector meson fields. Additionally, in order to describe the properties of neutron stars, the lagrangian density of the model includes the light lepton fields, which are essential to accomplish in the star charge neutrality and chemical equilibrium. In the framework of this parametric coupling Lagrangian model, we use our knowledge about the gravitational and baryon masses as well as on the intensity of the magnetic field of pulsar B of the double pulsar J07373039 to place constraints on the equation of state of nuclear matter under the assumption that pulsar B is formed in an electron-capture supernova event. With this aim, as a new formal feature, we introduce a systematic theoretical procedure to include many body nuclear interaction components in relativistic effective theories with derivative couplings in the presence of intense magnetic fields. Using recent observational data related to the gravitational and baryon masses of pulsar B of the double pulsar J07373039 as well as on its surface magnetic field, we impose new constraints on the mathematical parameters of the model, restricting and testing our parametric coupling approach in a broad range of values. Upon adjusting the parameters of the theory in order to describe bulk static properties of ordinary nuclear matter, we show that our approach represents a natural modeling of dense matter under the extreme physical conditions found in the interior of neutron stars. We then use the resulting approach to describe global static properties as well as the gravitational and baryon masses of neutron stars. Our predictions indicate an intimate connection between the criterion of naturalness and the exhaustion of the phase space of meson fields and genuine many-body forces: the addition of the whole fundamental baryon octet and many-body forces simulated by nonlinear self-couplings and meson-meson interaction terms improves the scope and the degree of naturalness of our effective model. On basis of our results, we advocate that naturalness plays a fundamental role in effective field theory and may represent a relevant criterion for model selection in the description of the properties of neutron stars.

  26. Ignacio Francisco Ranea-Sandoval (Facultad de Ciencias Astronómicas y Geofísicas, Universidad Nacional de La Plata, La Plata, Argentina)
    • Title of Poster Contribution (STARS2011): Instabilities in Kerr Spacetimes

      Gustavo Dotti, Reinaldo J. Gleiser and Ignacio Francisco Ranea Sandoval

      Abstract: In this work we generalize previous results regarding the stability under gravitational perturbations (s = ± 2) of super-extreme Kerr space-time which has a naked singularity and black hole interior beyond the Cauchy horizon. To do so we study solutions to the radial and angular Teukolsky's equations with different spin weight, particularly s= ±1 representing electromagnetic perturbations, s = ± 1/2 representing a perturbation by a Dirac field and s=0 representing perturbations by a scalar field. By analyzing the properties of radial and angular eigenvalues we prove the existence of an infinite family of unstable modes.

    • Title of Poster Contribution (SMFNS2011): Magnetars as Highly Magnetized Quark Stars: an analytical treatment

      Milva Orsaria, Ignacio Francisco Ranea Sandoval and Héctor Vucetich

      Abstract: We present an analytical model of a magnetar as a high density magnetized quark bag. The effect of strong magnetic fields (B > 5 1016 G) in the equation of state is considered. An analytic expression for the Mass-Radius relationship is found from the energy variational principle in general relativity. Our results are compared with observational evidences of possible quark and/or hybrid stars.

  27. Ignatios Antoniadis (Theory Division of CERN in Geneva, Switzerland)
    • Title of Talk (STARS2011): Physics from Extra Dimensions

      Ignatios Antoniadis

  28. Jason Nordhaus (Princeton University, Princeton, USA)
    • Title of Talk (SMFNS2011): Formation of High-Field Magnetic White Dwarfs from Common Envelopes

      Jason Nordhaus

      Abstract: The origin of highly magnetized white dwarfs has remained a mystery since their initial discovery. Recent observations indicate that the formation of high-field magnetic white dwarfs is intimately related to strong binary interactions during post-main-sequence phases of stellar evolution. If a low-mass companion, such as a planet, brown dwarf, or low-mass star, is engulfed by a post-main-sequence giant, gravitational torques in the envelope of the giant lead to a reduction of the companion’s orbit. Sufficiently low-mass companions in-spiral until they are shredded by the strong gravitational tides near the white dwarf core. Subsequent formation of a super-Eddington accretion disk from the disrupted companion inside a common envelope can dramatically amplify magnetic fields via a dynamo. Here, we show that these disk-generated fields are sufficiently strong to explain the observed range of magnetic field strengths for isolated, high-field magnetic white dwarfs. A higher-mass binary analogue may also contribute to the origin of magnetar fields.

  29. Javier Pardo Vega (Facultad de Física, Universidad de La Habana, Cuba)
    • Title of Poster Contribution (SMFNS2011): Photon Propagation in Casimir Vacuum

      Javier Pardo Vega and Hugo Pérez Rojas

      Abstract: By starting from the formal analogy with the temperature case, the dispersion equations for photons in a Casimir cavity are studied. The eigenvalues and eigenvectors are found in an approximation independent form. It is found two different eigenvalues and three eigenmodes. By using one-loop calculations, physical consequences are discussed.

  30. Joerg Aichelin (Université de Nantes/SUBATECH, Nantes, France)
    • Title of Talk (STARS2011): Kaon Condensates

      Joerg Aichelin

    • Title of Talk (SMFNS2011): News from Kaons in Matter

      Joerg Aichelin, C. Hartnack and A. Sood

      Abstract: We report about the recent findings in heavy ion experiments which explicitly exclude Kaon condensates at densities lower than 3ρ0.

  31. Jonathan Braithwaite (Universitaet Bonn, Bonn, Germany))
    • Title of Talk (SMFNS2011): Magnetic Deformation of Neutron Stars and Gravitational Radiation

      Jonathan Braithwaite

      Abstract: The magnetic field inside a star affects the mass distribution which, assuming the field is not symmetrical about the rotation axis, gives rise to the emission of gravitational radiation. I discuss simulations of various magnetic equilibrium, the induced change to the moments of inertia, and possible other observables such as the energy of supernovae and the angle of inclination between magnetic and rotation axes.

  32. Jorge Alfaro (Pontifícia Universidad Católica de Chile (PUC), Santiago, Chile)
    • Title of Talk (STARS2011): Delta Gravity and Dark Energy

      Jorge Alfaro

      Abstract: We present a model of the gravitational field based on two symmetric tensors. Outside matter, the predictions of the model coincide exactly with General Relativity, so all classical tests are satisfied. In Cosmology, we get accelerated expansion without a cosmological constant.

    • Title of Talk (SMFNS2011): Gauge Invariant Electrodynamics Motivated by a Spontaneous Breaking of the Lorentz Symmetry

      Jorge Alfaro

      Abstract: We introduce a new version of non-linear electrodynamics which is produced by a spontaneous symmetry breaking of Lorentz invariance induced by the non-zero expectation value of the gauge invariant electromagnetic field strength. The symmetry breaking potential is argued to effectively arise from the integration of massive gauge bosons and fermions in an underlying fundamental theory. All possible choices of the vacuum lead only to the remaining invariant subgroups T(2) and HOM(2). We explore in detail the plane wave solutions of the linearized sector of the model for an arbitrary vacuum. They present two types of dispersion relations. One is the usual one, with fields similar to the Maxwell fields. The other dispersion relation involves anisotropies determined by the structure of the vacuum. The corresponding fields reflect these anisotropies. The model is stable in the small Lorentz invariance violation approximation. We have also embedded our model in the photon sector of the Standard Model Extension, in order to translate the many bounds obtained in the latter into corresponding limits for our parameters. The one-way anisotropic speed of light is calculated for a general vacuum and its isotropic component is strongly bounded by \tilde \delta c/c < 2 X 10-32. The anisotropic violation contribution is estimated by introducing an alternative definition for the difference of the two-way speed of light in perpendicular directions, \Delta c, that is relevant to Michelson-Morley type of experiments and which turns out to be also strongly bounded by \Delta c/c < 10-32. Finally, we speculate on the relation of the vacuum energy of the model with the cosmological constant and propose a connection between the vacuum fields and the intergalactic magnetic fields.

  33. Jorge Armando Rueda Hernandez (Università degli Studi di Roma "La Sapienza", Roma, Italy)
    • Title of Talk (STARS2011): Neutron Star Equilibrium Configurations including Weak, Electromagnetic and Strong Interactions within General Relativity

      Jorge Armando Rueda Hernandez, Remo Ruffini and She-Sheng Xue

      Abstract: The equilibrium equations of neutron stars including weak, electromagnetic and strong interactions within general relativity are presented and solved numerically. It is emphasized the crucial role of the constancy of the generalized Fermi energies of particles in determining the core-crust boundary conditions.

  34. Jorge E. Horvath (Instituto Astronômico e Geofísico da Universidade de São Paulo (IAG/USP), São Paulo, Brazil)
    • Title of Talk (STARS2011): Open Problems

      Jorge E. Horvath

    • Title of Talk (STARS2011): The Mass Distribution of Neutron Stars

      Jorge E. Horvath, R. Valentim and E. Rangel

    • Title of Talk (SMFNS2011): Final Discussion (Round Table)

      Jorge E. Horvath

    • Title of Talk (SMFNS2011): Self-bound Stars are/are not Severely Limited by New Data

      Laura Paulucci, M.G.B. de Avellar and Jorge E. Horvath

  35. José Antonio de Freitas Pacheco (Observatoire de la Côte d'Azur (OCA), Nice, France)
    • Title of Talk (STARS2011): The Evolution of the Distribution of Baryons in the Universe from Cosmological Simulations

      José Antonio de Freitas Pacheco and F. Durier

      Abstract: Baryons are found locked in stars and in a gaseous phase forming the interstellar gas and the intergalactic medium. The fraction of hydrogen and metals in these different components evolves in time, reflecting the action of different processes like star formation and feedback either from supernovae and AGNs. The evolution of these different components resulting from cosmological simulations will be reported and compared with recent observational data.

  36. Karl Jansen ( NIC, DESY, Zeuthen, Germany)
    • Title of Talk (STARS2011): The Strange Content of the Nucleon

      Karl Jansen

      Abstract: We give an overview about lattice computations of the strange quark content of the nucleon. Such calculations are important for super-symmetric dark matter scenarios.

    • Title of Talk (SMFNS2011): Strange Quark Physics

      Karl Jansen

      Abstract: Various aspects of strange quark physics as computed from lattice calculations are discussed. Topics include the strange quark mass, decay constants and meson and baryon masses.

  37. Karsten Jedamzik (University of Montpellier, France)
    • Title of Talk (STARS2011): Big Bang Nucleosynthesis

      Karsten Jedamzik

      Abstract: The status of Big Bang nucleosynthesis is discussed. After establishing that their is a factor three-five discrepancy between the predicted and observationally inferred primordial 7Li abundance, I discuss possible stellar physics, nuclear physics, and physics beyond the standard model resolutions to this problem.

  38. Kuantay Boshkayev (Università degli Studi di Roma "La Sapienza", Roma, Italy)
    • Title of Poster Contribution (STARS2011): On the Minimum Rotation Period of Rotating White Dwarfs

      Kuantay Boshkayev, Jorge Rueda, and Remo Ruffini

      Abstract: The properties of rotating white dwarfs are calculated within the framework of general relativity. The Hartle-Thorne formalism is applied to construct self-consistently the internal and the external solution to the Einstein equations. Within this formalism we calculate the mass, the radius, the moment of inertia, the eccentricity and the quadrupole moment of rotating white dwarfs as a function both of the central density and the rotational period of the star. The minimum rotation period (maximum angular velocity) for stable configurations has been obtained as well as the contribution of rotation to the maximum mass of white dwarfs.

  39. Lauro Tomio (Universidade Federal Fluminense (UFF), Niterói, Brazil)
    • Title of Talk (STARS2011): Exotic Carbon Systems in Two-neutron Halo Three-body Models

      Lauro Tomio, Antonio Delfino, M. T. Yamashita, and Tobias Frederico

      Abstract: Within a renormalized zero-ranged three-body model, we discuss the general properties of exotic carbon systems, considering them as a core with two-neutron halo. The qualitative properties of such systems can be studied within a three-body model with a s-wave zero-range interaction, suitable for large two-body scattering lengths, or weakly bound subsystems. The low-energy properties of large three-body systems are universal and dominated by the Efimov effect, where the details of the interaction are less important. The three-body properties are set by low-energy parameters (scales), as the binding energy of the halo to the core, which is assumed to be structureless, and the corresponding scattering lengths of the two-body subsystems. The condition for the appearance of one excited state in the maximally symmetric configuration of a three-body halo system in the Efimov limit (infinite scattering lengths) defines a universal map. The boundary separates a region in the parametric space where excited states are possible. By crossing the critical boundary, a bound subsystem becomes a virtual state. We study the particular case of Carbon-20, modeled as n-n-Carbon-18 system, where Carbon-19 is bound; and also the Carbon-22, which is a Borromean system with all subsystems unbound.

  40. Liuba Peñate (Universidad Central de Las Villas, Santa Clara, Cuba)
    • Title of Poster Contribution (SMFNS2011): Environmental Effects of Flares from Red Dwarf Stars

      Liuba Peñate, Rolando Cárdenas and Osmel Martín

      Abstract: We examine some environmental effects appearing on exoplanets in the habitable zone of red dwarfs, during the first billion years of the star evolution. We focus on the radiative perturbation that the frequent stellar flares would cause on the planet surface and down the assumed planetary ocean, with some insight on the affectation of potential life forms.

  41. Luciano Rezzolla (Albert Einstein Institute, Max Planck Institute for Gravitational Physics, Potsdam, Germany)
    • Title of Talk (STARS2011): Modeling the Inspiral and Merger of Binary Neutron Stars

      Luciano Rezzolla

      Abstract: Investigating the final evolution of neutron stars binaries promises to be particularly rewarding. These systems are in fact excellent sources of gravitational waves, they are thought to behind the powerful engines powering short gamma-ray bursts, and they can unveil the behaviour of matter at extreme densities and temperatures. I will review the present understanding in the modeling the inspiral and merger of binary neutron stars in full general relativity, underlining the considerable recent progress both in hydrodynamics and in MHD. Finally, I will discuss the steps that still need to be taken to use this progress to model the central engine of short gamma-ray bursts.

  42. Luis Antonio Cabral (Universidade Federal de Tocantins (UFT), Palmas, Brazil)
    • Title of Poster Contribution (STARS2011): Conserved Quantities and Dualities for Particles in Curved Spacetime

      Luis Antonio Cabral

      Abstract: We consider particles moving in curved spacetime and symmetries in such gravitational background. According to spacetime isometries, we obtain the Killing vectors corresponding to a specific spacetime metric. We use a generalized Killing equation and search for solutions involving Killing tensors associated with the metric. With these tensors some conserved quantities are constructed and they are valid along particles geodesic. In the Hamiltonian formalism for these particles, the conserved quantities can generate a dual description of the metric. We construct nontrivial dual metrics and consider a kind of geometric duality that involves completely different spacetimes. From these metrics we consider geometric invariants and examine the singularity structure of the dual spacetime.

  43. Magno V.T. Machado (Universidade Federal do Rio Grande do Sul (UFRGS), Porto Alegre, Brazil)
    • Title of Talk (STARS2011): Geometric Scaling in Ultrahigh Energy Neutrinos and Nonlinear Perturbative QCD

      Magno V.T. Machado

      Abstract: It is shown that in ultrahigh energy inelastic neutrino-nucleon(nucleus) scattering the cross sections for the boson-hadron(nucleus) reactions should exhibit geometric scaling on the single variable tauA =Q2/Q2sat,A. The dependence on energy and atomic number of the charged/neutral current cross sections are encoded in the saturation momentum Qsat,A. This fact allows an analytical computation of the neutrino scattering on nucleon/nucleus at high energies, providing a theoretical parameterization based on the scaling property.

  44. Marcus Bleicher (Institut für Theoretische Physik, Universitaet Frankfurt, Germany)
    • Title of Talk (STARS2011): Micro Black Holes in the Laboratory

      Marcus Bleicher

      Abstract: We present a short overview on the ideas of large extra-dimensions and their implications for the possible production of micro black holes in the next generation particle accelerators, e.g. the LHC at CERN. In fact, the possibility of black hole production on earth is currently one of the most exciting predictions for the LHC accelerator and would change our current understanding of physics radically. We will also discuss possible other observables for colliders and for cosmic ray physics.

  45. Martin Sprenger (Institut für Theoretische Physik, Universitaet Frankfurt, Germany)
    • Title of Poster Contribution (STARS2011): Neutrino Oscillations as a Novel Probefor a Minimal Length

      Martin Sprenger, P.Nicolini and Marcus Bleicher

      Abstract: In quantum gravity, the smooth picture of space-time we are familiar with should be replaced by a space-time that is subject to quantum fluctuations. Even though no complete description yet exists, most candidate theories of quantum gravity agree on the emergence of a minimal length at the fundamental scale. Structures smaller than this length scale lose operational meaning which introduces radical changes in particle and black hole physics. In this talk, we present a phenomenological, model-independent description of the effects of a minimal length and propose neutrino oscillations as a viable probe for these effects.The modifications of the oscillation probabilities allow a comparison with experimental data and we will present bounds on the value of the minimal length.

  46. Miriani G. Pastoriza (Universidade Federal do Rio Grande do Sul (UFRGS), Porto Alegre, Brazil)
    • Title of Talk (STARS2011): The Eco-system of Active Galactic Nuclei: perspective from the Infrared light

      Miriani G. Pastoriza, Rogeiro Riffel and Dinalva Sales

      Abstract: The infrared spectral region is a very adequate window to study the eco-system formed by the stars, ionized and molecular gas, and the super-massive black hole hosted in the central few parsecs of active galactic nuclei. From image and spectroscopic observations we searched the chronology of the star formation events and its connection with the central energy source. The observed continuum emission in the Near Infrared ( 0.8- 2.4 µm) together with the Silicates absorption at 10 µm, is used to determine the geometry and dimension of the dusty torus, which hide the accretion disk and the ionized turbulent clouds of Seyfert 1 galaxies. The chemical composition and physical conditions of the dust are derived from the observation of the Polycyclic Aromatic Hydrocarbons emission bands at 6.2μm, 7.7μm, 8.6μm, 11.2μm and 12.7μm. Finally the role played by the accretion (dust, gas and stars) and interaction between galaxies is analyzed as a mechanism to feed and grow the central super-massive Black Hole.

  47. Moisés Razeira (Universidade de Caxias do Sul (UCS), Caxias do Sul, Brazil)
    • Title of Poster Contribution (STARS2011) (proposal): A Relativistic Effective Model with Parameterized Couplings for Neutron Stars

      Moisés Razeira, Alexandre Mesquita, and César Zen Vasconcellos

      Abstract: We present a relativistic effective model with derivative couplings which includes genuine many-body forces simulated by nonlinear interaction terms involving scalar-isoscalar, vector-isoscalar, vector-isovector, scalar-isovector mesons. The effective model presented in this work has a philosophy quite similar to the original version of the model with parameterized couplings. But unlike that, in which the parametrization is directly inserted in the coupling constants of the Glendenning model, we present here a method for the derivation of the parametric dependence of the coupling terms, in a way that allows in one side to consistently justify this parametrization and in the other to extend in a coherent way the range of possibilities of parameterizations in effective models with derivative couplings. The extended model is then applied to the description of neutron stars.

    • Title of Poster Contribution (STARS2011) (proposal): Dispersion Relations for Gluononium

      Moisés Razeira, Alexandre Mesquita, Marcos Rodriguez, Mário Luiz Lopes da Silva, Francisco Fernández, and César Zen Vasconcellos

      Abstract: We investigate relativistic bound states for a hypothetical light scalar gluino pair (gluinonium), in the framework of the covariant Bethe-Salpeter equation (BSE). In this paper, we derive, from the covariant BSE for a fermion-anti-fermion system, using charge conjugation, the corresponding bound-state equation for a gluino pair and we then formulate, for a static harmonic kernel the coupled differential equations for the corresponding static Bethe-Salpeter amplitude. The steps of our approach then include a numerical solution of the Bethe-Salpeter amplitude for a two-body interaction consisting of scalar, pseudo-scalar, and four-vector components and the determination of the energy spectrum for the ground and the radially excited states of massive gluinonium. We found the energy spectrum and radial distributions of fundamental and excited states of gluinonium. Our results show striking similarities of two non relativistic constituent quark model.

    • Title of Poster Contribution (STARS2011) (proposal): Neutron Stars as Dark Matter

      Moisés Razeira, Alexandre Mesquita, José Eduardo Costa, César Zen Vasconcellos, and Francisco Fernández

      Abstract: We examine theoretical possibilities of extending the range of maximum and minimum mass values of stable configurations of neutron stars and pulsars using Le Chatelier Principle. Guided by the ``observed'' values of hadronic masses of dark matter (MACHOs), we go one step beyond other hadrodynamics approaches still studying global properties of possible sequences of compact stars in hydrostatic equilibrium. Our treatment leads to equilibrium configurations whose properties are more complex than those predicted by other treatments. Using an extended version of the effective relativistic parameterized coupling model we determined the limits of stable configurations of neutron stars and pulsars by considering different possible choices of effective parameters, enlarging the scope of the theory and the presence of mesons of the light and heavy sectors as well as nucleons, hyperons and leptons. We find in this work stable configurations of neutron stars with masses larger than 2 times the solar mass. These objects, when present in sufficient quantities in the halo of the galaxy, could be observed through the gravitational microlensing method as dark matter.

  48. Osmel Martín (Universidad Central de Las Villas, Santa Clara, Cuba)
    • Title of Poster Contribution (SMFNS2011): Effects of Galactic Gamma Ray Bursts on Planetary Atmospheres and Biospheres

      Osmel Martín, Rolando Cárdenas Ortiz, Jorge Horvath and Liuba Peñate

      Abstract: We examine the effects that a galactic gamma ray burst would cause on planetary atmospheres with and without ultraviolet screeners. We assume a spectrum of the gamma ray burst coming from a massive star and use a radiative transfer model in the atmospheres considering mainly photo-absorption and Compton scattering. Then we focus on the re-emission of aurora like spectra due to the action of secondary electrons and finally estimate the distances at which highly evolved massive stars can be dangerous for planetary atmospheres and biospheres.

  49. Ovidiu Tesileanu (University of Bucharest, Romania)
    • Title of Talk (SMFNS2011): Magnetic Fields and Radiative MHD Simulations of YSO Jets

      Ovidiu Tesileanu, Silvano Massaglia, and Andrea Mignone

      Abstract: During star formation, there is a phase when the emission of jets is likely to occur. Many efforts were done lately, with the increase in available computational power, towards the numerical modeling of these flows. Magnetic field seems to be a key ingredient not only in jet formation, but also in large-scale propagation, affecting the radiative emission properties of the jet plasma. We will present the results of such radiative MHD simulations, including a complex ionization network and cooling function, and our approach to "synthetic observations" of stellar jets.

  50. Owen Pavel Fernández Piedra (Universidad de Cienfuegos, Cuatro Caminos, Cienfuegos, Cuba)
    • Title of Poster Contribution (STARS2011): Vacuum Polarization Effects on Quasinormal Modes

      Owen Pavel Fernández Piedra and Jeferson de Oliveira

      Abstract: In this work we studied the influence of vacuum polarization of quantum massive fields on the quasinormal spectrum of four-dimensional Reissner-Nordström black holes. First, we consider a mixture of quantum massive fields interacting with gravity near a black hole in order to calculate its quantum stress-energy tensor using the Schwinger-De Witt expansion. Having the expression the stress-energy tensor we solve perturbatively the back reaction problem due to these quantum fields upon the background space-time, obtaining a semi-classical charged black hole solution that take into account the gravitational vacuum polarization of the quantum fields. As a next step we consider the evolution of a probe classical massless scalar field in the background of the semi-classical black hole, and determine, using a sixth order WKB expansion of the effective potential, the quasi-normal frequencies of the perturbation through the solutions of the wave equation with the specific boundary conditions requiring pure outgoing waves at spatial infinity and pure incoming waves on the event horizon. As a remarkable result, we observed a shift in the quasi-normal spectrum due to the vacuum polarization of quantum fields in semiclassical Reissner-Nordström black holes, more pronounced for the fundamental mode. Through the calculation of the quality factor of the oscillations, we conclude that the semi-classical black hole is a better oscillator than their bare classical partner.

    • Title of Poster Contribution (STARS2011): Spinor Perturbations in Four Dimensional Stringy Black Holes

      Owen Pavel Fernández Piedra and Jeferson de Oliveira

      Abstract: In this work we study Weyl fermion perturbations in four dimensional black holes of string theory, obtained either from a non-extreme configuration of three intersecting five-branes with a boost along the common string or from a non-extreme intersecting system of two two-branes and two five-branes. We obtain the Dirac equation for Weyl spinor field evolving near a four-dimensional stringy black hole, and after conformal re-scaling of the metric, we perform a numerical integration of it to observe the time evolution of the fermion perturbation in this particular spacetime. Specifying as boundary conditions the presence of only pure outgoing waves at spatial infinity and pure incoming waves on the event horizon, we compute the complex frequencies that dominate quasi-normal ringing using two methods: a numerical Prony fitting of the time domain data and a semi-analytical sixth order WKB approach, and present an analytical expression for the quasi-normal frequencies in the limit of large angular momentum. We also perform a numerical investigation of the relaxation of spinor perturbations in stringy black holes at very long times, and show that the falloff is identical to those appeared for massless fields outside other four-dimensional black hole solutions in classical general relativity.

    • Title of Poster Contribution (STARS2011): Object Picture, Quasinormal Modes and Long Time Relaxation of Rarita-Schwinger Perturbations in Four Dimensional Static Black Holes

      Owen Pavel Fernández Piedra

      Abstract: The evolution of massless gravitino perturbations in four dimensional static black holes is studied in detail. First, we write the perturbation equations for Rarita-Schwinger fields in a general background spacetime corresponding to a static solution of Einstein fields equations without cosmological constant. In the specific case of Schwarzschild and Reissner-Nordström black holes, we perform a separation of variables to leave the problem in a form suitable for numerical integration of the evolution equations. Using a characteristic integration scheme, we obtain the profiles that describe the evolution of gravitino perturbations outside static black holes, and concludes that this evolution involves the usual three stages developed by fields of other spin: a transient epoch strongly dependent on the initial conditions, a quasi-normal ringing state for intermediate times and a very long time power law fall-off. We determine the quasi-normal frequencies numerically using an adequate fitting method of the data profile, and also using a semi-analytical sixth order WKB approximation. We also make similar calculations to determine the response of a static black hole for boson and Dirac perturbing fields and show that the quality factor becomes a decreasing function of the spin for boson perturbations, whereas the opposite situation appears for fermion ones. With respect to the late-time behaviour, we found numerical evidence of a faster decay of gravitino perturbations, a result in constrast to that known for the other neutral fields.

    • Title of Poster Contribution (STARS2011): The Evolution of Dirac fields in the Horowitz-Maldacena-Strominger Black Hole with U(1) Charges

      Owen Pavel Fernández Piedra, Yulier Jiménez Santana and Fidel Sosa

      Abstract: The aim of this report is to discuss results concerning the study of weak Weyl fermion waves propagating outside five dimensional black hole solutions with U(1) charges constructed from string-brane theory. We solve the Dirac equation for spin 1/2 fields in general d-dimensional spherically symmetric spacetimes, and uses this results to determine numerically the complete time evolution of this massless perturbations in the given metric. Quasi-normal ringing followed by long time tails are clearly observed for all values of charges, and constitutes a good evidence for the stability of this higher dimensional compact objects under fermion perturbations. Specifying as boundary conditions the presence of only pure outgoing waves at spatial infinity and pure incoming waves on the event horizon, we compute numerically and semi-analytically the quasi-normal frequencies. We also present an analytical expression for the quasi-normal frequencies in the large angular momentum limit obtained using the first order WKB approximation that gives the exact result in this case. The power law exponents that describes the relaxation of the field at very long times are numerically computed, showing that fermion and boson fields decay identically in this particular gravitational background.

    • Title of Poster Contribution (STARS2011):Scalar Field Evolution in d-dimensional Black Holes from String Theory

      Elcio Abdalla, Owen Pavel Fernández Piedra and Jeferson de Oliveira

  51. Peter O. Hess (Universidad Nacional Autónoma de México (UNAM), Mexico)
    • Title of Talk (STARS2011): Pseudo-Complex General Relativity

      Peter O. Hess and Walter Greiner

      Abstract: General Relativity is extended to the pseudo-complex coordinates. We discuss the formulation of the theory and the projection to real numbers. The case of a central massive body (Schwarzschild) and of the Robertson-Walker universe. It is shown that the pseudo-complex formulation introduces a dark energy, which accumulates around massive bodies and finally prevents the formation of a black hole. In the case of the Robertson-Walker universe, the dark energy accelerates the universe. Several new solutions are found.

    • Title of Talk (to SMFNS2011): Solvable Models and Hidden Symmetries in QCD

      Peter O. Hess

      Abstract: The Hamiltonian of QCD at low energy is divided in a main and a perturbative part. The main restriction is to a finite volume. For the main part of the Hamiltonian analytic solutions can be found, including up to three orbital levels. For an arbitrary number of orbitals, two successive unitary transformations are applied leading again to an analytic solution.

  52. Peter Schiffer (RWTH Aachen Universitaet, Aachen, Germany)
    • Title of Talk (SMFNS2011): Constraining Cosmic Magnetic Fields Using the Pierre Auger Observatory

      Peter Schiffer (for the Pierre Auger Collaboration)

      Abstract: Being most likely charged particles, ultra high energy cosmic rays (UHECRs) are deflected in cosmic magnetic fields and thus offer the possibility for constraining these fields. As the deflection strength depends on the energies of the UHECRs, an energy ordering in the arrival directions of UHECRs is expected for a wide range of source and magnetic field scenarios. The Pierre Auger Observatory, as the world´s largest experiment for the measurement of UHECRs, offers the opportunity for the search of structure in their arrival directions. The results of anisotropy searches at the Pierre Auger Observatory are reviewed with a special emphasis on cosmic magnetic fields. In addition to that novel methods for constraining these magnetic fields are discussed and their prospect is explored by using Monte Carlo models of cosmic magnetic fields and UHECR source distribution.

  53. Remo Ruffini (Università degli Studi di Roma "La Sapienza", Roma, Italy)
    • Title of Talk (STARS2011): The Need of Critical Fields in Neutron Stars and Black Holes from Gamma Ray Bursts

      Remo Ruffini

  54. Renxin Xu (Peking University, Beijing, China)
    • Title of Talk (STARS2011): Pulsars: Gigantic Nuclei

      Renxin Xu

      Abstract: Because of the strong coupling between quarks of cold matter in realistic compact stars, quarks could be clustered together there, even in a solid state. Although such kind of matter would be similar to nuclear matter,we call it still as "quark" matter since quark degree of freedom appears during the formation and stars composed by this matter behavior like conventional quark stars rather than normal neutron stars in astrophysics. Arguments from a model in-dependent point of view are presented, that realistic quark matter could be in a solid state which could be necessary to understand different manifestations of pulsar-like stars. One of the key differences between fluid and solid quark stars is relevant to starquakes: the former cannot have while the latter can.

    • Title of Talk (SMFNS2011): Magnetars: fact or fiction?

      Renxin Xu

      Abstract: It is a hot topic that compact stars with extremely strong magnetic fields,~ 10[14-16]G, so called "magnetars" would exist in the Universe; however, we are questioning this speculation from both theory and observation. The power source of AXPs/SGRs is actually the magnetic energy through field-reconnection in magnetar model, while we think that star quake-induced elastic and gravitational energies could possibly power the bursts of SGRs and AXPs in a solid compact star model. An AIQ (accretion-induced star-quarke) model is presented and discussed.

  55. Ricardo Gonzalez Felipe (Instituto Superior de Engenharia de Lisboa (ISEL) and Instituto Superior Técnico (IST), Lisboa, Portugal)
    • Title of Talk (STARS2011): Neutrinos and the Matter-antimatter Asymmetry in the Universe

      Ricardo Gonzalez Felipe

  56. Riccardo Belvedere (Università degli Studi di Roma "La Sapienza", Roma, Italy)
    • Title of Poster Contribution STARS2011): Mass, Radius and Moment of Inertia of Neutron Stars

      Riccardo Belvedere, Jorge Rueda Hernandez, and Remo Ruffini

    • Abstract: We formulate and integrate numerically the set of self-consistent ground-state equilibrium equations for neutron stars taking into account quantum statistics, electro-weak and strong interactions within the framework of general relativity. The strong interaction between nucleons in the neutron star core is modeled through the sigma-omega-rho meson exchange in the context of the extended Walecka approach. This solution differs from the traditional one in that the global charge neutrality is imposed as contrasted to the local charge neutrality. The electrodynamical structure in the interface between the core and the crust is examined and the presence of overcritical electric fields inferred. Specific examples of equilibrium configuration are given fulfilling the Einstein-Maxwell-Thomas-Fermi equations with the boundary conditions implying a precise eigenvalue problem.
  57. Roberto A. Sussman (Universidad Nacional Autónoma de México (UNAM), Mexico)
    • Title of Talk (STARS2011): Non-spherical Voids: the best available challenge to the dark energy paradigm

      Roberto A. Sussman

  58. Rodrigo Picanço Negreiros (Frankfurt Institute for Advanced Studies (FIAS), Johann Wolfgang Goethe University, Frankfurt am Main, Germany)
    • Title of Talk (STARS2011): Composition, Structure, and Thermal Evolution of Magnetized and Rotating Compact Stars

      Rodrigo Picanço Negreiros, Stefan Schramm, Fridolin Weber and Igor Mishustin

  59. Rolando Cardenas Ortiz (Universidad Central de Las Villas, Santa Clara, Cuba)
    • Title of Talk (STARS2011): Effects of Galactic Gamma Ray Bursts on Planetary Atmospheres and Biospheres

      Osmel Martín, Rolando Cárdenas Ortiz, Jorge Horvath and Liuba Peñate

      Abstract: We examine the effects that a galactic gamma ray burst would cause on planetary atmospheres with and without ultraviolet screeners. We assume a spectrum of the gamma ray burst coming from a massive star and use a radiative transfer model in the atmospheres considering mainly photo-absorption and Compton scattering. Then we focus on the re-emission of aurora like spectra due to the action of secondary electrons and finally estimate the distances at which highly evolved massive stars can be dangerous for planetary atmospheres and biospheres.

  60. Rosana de Oliveira Gomes (Universidade Federal do Rio Grande do Sul (UFRGS), Porto Alegre, Brazil)
    • Ttile of Poster Contribution (STARS2011): Mass-Radius Relation for Hybrid Stars Under Deconfinment Phase Transition

      Rosana de Oliveira Gomes, Moisés Razeira, Alexandre Mesquita, Francisco Fernández and César Zen Vasconcellos

  61. Sérgio Szpigel (Universidade Presbiteriana Mackenzie, São Paulo, Brazil)
    • Title of Poster Contribution (STARS2011): Subtractive Renormalization in Effective Field Theories for Nuclear Forces

      Sérgio Szpigel, Varese S. Timóteo and Francisco de O. Durães

      Abstract: The standard procedure for the renormalization of nucleon-nucleon (NN) interactions in the context of Weinberg’s approach to chiral effective field theory (ChEFT) consists of two steps. The first step is to solve the Lippmann-Schwinger (LS) equation for the scattering amplitude with an effective NN potential which consists of pion-exchange interactions and contact interaction terms. This requires the use of a regularization scheme in order to overcome the ultraviolet divergences generated in the momentum integrals when the NN potential is iterated. The second step is to determine the strengths of the contact interactions, the so called low-energy constants (LEC's), by fitting a set of low-energy scattering data. Once the LEC´s are fixed for a given regularization scale, the LS equation can be solved to evaluate other observables. The most common scheme used to regularize the LS equation is to introduce a cutoff regularizing function that suppresses the contributions from the potential matrix elements for momenta larger than a given cutoff scale, thus eliminating the ultraviolet divergences in the momentum integrals. An alternative approach is the subtractive renormalization or subtracted kernel method (SKM) in which, instead of using a cutoff function, the LS equation is regularized by performing subtractions in the kernel at a given energy scale. An advantage of the SKM approach is that it can be extended to any derivative order of the contact interactions through a recursive process involving multiple subtractions. In this work we study the subtractive renormalization of NN interactions both in pionless EFT and in ChEFT up to next-to-next-to-leading order (NNLO). We apply the SKM approach to describe the NN scattering in the 1S0 partial-wave channel and show by explicit numerical calculations that the procedure is fully renormalization group invariant with respect to the change of the subtraction scale through a non-relativistic Callan-Symanzik equation.

    • Title of Talk (SMFNS2011): Similarity Renormalization Group Evolution of Nuclear Forces

      Sérgio Szpigel, Varese S. Timóteo and Francisco de O. Durães

      Abstract: The Similarity Renormalization Group (SRG) is a method based on a series of continuous unitary transformations that evolve hamiltonians with a cutoff on energy differences. Viewing the hamiltonian as a matrix in a given basis, the SRG transformations suppress off-diagonal matrix elements as the cutoff is lowered, driving the Hamiltonian towards a band-diagonal form. Recently, the SRG has been used as a tool to evolve both phenomenological and chiral effective field theory (ChEFT) nucleon-nucleon (NN) potentials to phase-shift equivalent softer forms, effectively decoupling low-energy observables from high-energy degrees of freedom. It has been shown that such a decoupling leads to more perturbative NN potentials, improving convergence and simplifying calculations in nuclear few- and many-body problems. An alternative renormalization group method that has been applied in this context is the Vlow-k approach, in which the hamiltonians are evolved with a cutoff on momenta. In this work we study the SRG evolution of ChEFT NN interactions at leading order (LO) derived within the framework of the Subtracted Kernel Method (SKM), a renormalization scheme based on a subtracted scattering equation. We apply the SRG transformation to evolve the SKM-LO ChEFT potential in the 1S0 and the 3S1-3D1 partial-wave channels and analyze the decoupling pattern between low- and high-momentum components. The results are compared with those obtained for other NN potentials, such as the Nijmegen II, the Argonne V18 and the chiral N3LO potential of Entem and Machleidt.

  62. Stefan Schramm (Frankfurt Institute for Advanced Studies (FIAS), Johann Wolfgang Goethe University, Frankfurt am Main, Germany)
    • Title of Talk (STARS2011): Dense Matter and Neutron Stars in Parity-Doublet Formulations of Chiral Symmetry

      Stefan Schramm

      Abstract: There are various formulations of chirally symmetric systems of hadrons. In this talk I will discuss the so-called parity-doublet formulation, where in addition to the nucleon its corresponding state with opposite parity is included. One advantage of this approach is the possibility of defining a chirally symmetric effective mass term in the Lagrangian. In this formulation the signal for chiral symmetry breaking is the onset of mass degeneracy of the parity partners. I will show results for dense isospin-symmetric hadronic matter and the possibility of first-order chiral phase transitions or a smooth cross-over depending on parameters. In addition I will discuss neutron star matter in beta equilibrium and the resulting properties of neutron stars. In an extension of this calculation I will present a SU(3) formulation of the parity doublet model, its phase structure as well as the resulting neutron star properties.

    • Title of Talk (SMFNS2011): Nuclear Matter, Nuclei and Neutron Stars in a Quark-Hadron Model

      Stefan Schramm

      Abstract: One of the difficulties in describing chiral symmetry and deconfinement phase transitions in strongly interacting matter at high temperatures as well as at high densities stems from the fact that one has to deal with very different degrees of freedom at both sides of the phase transition, i.e. hadrons at low temperatures/densities and quarks and gluons in the other extreme. Glueing two separate equations of state together will necessarily lead to first-order phase transitions (which are not expected, at least not at small densities and high temperatures). In order to remedy this problem a unified model of quarks and hadrons (the QH model) has been developed that integrates both degrees of freedom in an effective chiral flavor-SU(3) ansatz. I will show results for nuclear matter, nuclei and neutron stars, including effects of strong magnetic fields, for the purely hadronic part of the theory and then results for excited matter and stars for the full QH model. Various extensions of this approach will be discussed.

  63. Thomas Boller (Max-Planck-Institut fuer extraterrestrische Physik, Garching, Germany)
    • Title of Talk (STARS2011): Precision Measurements in the Galactic Center

      Thomas Boller

      Abstract: The Galactic Center (GC) is a uniquely accessible laboratory for exploring a broad range of scientific questions related to the interaction of a massive black hole (MBH) with its environment. I highlight two central aspects: The stellar orbits and the flares from the MBH. Stellar orbits show that the gravitational potential to a scale of a few light hours is dominated by a concentrated mass associated with the compact radio source Sgr A*. I discuss the strong observational facts that Sgr A* is a MBH but also still alternative explanations. Once per day Sgr A* exhibits infrared flares during which its flux increases by a factor 10-50. Flares are probably due to synchrotron emission of transiently heated electrons in the innermost accretion zone.

    • Title of Talk (SMFNS2011): Probing the Strong and Weak Field Limit in Active Galaxies with Soft X-rays

      Thomas Boller

      Abstract: Strong X-ray reflection is a natural consequence for the existence of a compact corona close to the central black hole disc system in active galaxies. Recently we (Boller, Mueller 2010) showed that a very close reflector is described by high emissivity indices of about 6, inner disc radii of about 3 RG, resulting into black hole spins of about 0.8, high metallicities and strong Compton broadening effects. The FWHM values of the emission of many unresolved lines centred at line blends at around 0.33 and 0.6 keV are of the order of c/3. The very nearby reflector probes the strong field limit in active galaxies. Furthermore, an acceptable data fit requires additional less broadened soft X-ray lines which are farther away from the black hole and which probe the weaker field limit. The current generation of X-ray observatories, particularly Chandra and XMM-Newton, have provided new insights into the astrophysics and the demographics matter under strong gravity. I will review this progress, and look forward to how this work may be taken forward in the future with eROSITA, the International X-ray Observatory (IXO), and a new X-ray observatory concept, GRAVITAS.

  64. Walter Greiner (Frankfurt Institute for Advanced Studies (FIAS), Johann Wolfgang Goethe University, Frankfurt am Main, Germany)
    • Title of Talk (STARS2011): Extension of the Periodic System: Superneutronic, Superheavy, Superstrange Elements

      Walter Greiner

      Abstract: The extension of the periodic system into various new areas is investigated. Experiments for the synthesis of super-heavy elements and the predictions of magic numbers are reviewed. Different ways of nuclear decay are discussed like cluster radioactivity, cold fission and cold multi-fragmentation. Up to now super-heavy nuclei were only produced close to the proton drip line. The recent Dubna experiments utilizing a 48Ca beam have been confirmed at an essential intermediate decay at GSI. Thus we can state that super-heavy nuclei up to Z = 118 have been found. In order to make super-heavies closer to the stable valley by increasing the neutron number we investigate the bombardment of e.g. U+Cm and its decay down to the super-heavy island around Z = 114 and 120. In this connection also the time delay in the formation of the giant nuclear system U+Cm up to 10-19 sec is found. This is most important for studying the decay of the super-critical electron-positron vacuum. A trigger for such giant nuclear systems with long delay times (~ 10-19s) is e.g. large mass transfer, e.g. U+Cm →Pb+rest. In this connection the basics of the decay of the vacuum in super-critical Coulomb fields is reminded. A very important, novel idea came up a number of years ago in work with K. Gridnev, D. Gridnev, V. Tarasov and St. Schramm. We suggested that extremely neutron rich nuclei might exist, i.e. nuclei like 42O, 42Mg, 42Al, 260Pb, etc. Meanwhile we extended this investigation along the neutron drip line and found extended riches and islands of extreme neutron nuclei. This opens the door to an extremely wide and new field of research, which is very important in nuclear astrophysics. Long living super-heavy nuclei with sufficiently large neutron number can be produced in macroscopic quantities by double-atomic-bomb explosions in deep underground or by pulsed reactors with sufficiently high neutron flux. A perspective for future research is given. This includes also a theoretical study of super-heavy element (SHE) formation by supernova explosions and thus the possible occurrence of SHE in nature. Furthermore, investigations on hyper-nuclei and the possible production of antimatter-clusters in heavy-ion collisions are reported. Various versions of the meson field theory serve as effective field theories as the basis of modern nuclear structure and suggest structure in the vacuum which might be important for the production of hyper- and antimatter. I also discuss the possibility of producing a new kind of nuclear systems by putting a few antibaryons inside ordinary nuclei. This leads to surprising results: in particular to cold compression of nuclear matter- in contrast to hot compression via nuclear shock waves.

  65. Xiaoyu Lai (Peking University, Beijing, China)
    • Title of Talk (STARS2011): Quark Matter in the Early Universe

      Xiaoyu Lai

      Abstract: Strange quark nuggets (SQNs) could be the relics of the cosmological QCD phase transition, and they could very likely be the candidate of cold quark matter if survived the cooling of the later Universe, although the formation and evolution of these SQNs depend on the physical state of the hot QGP (quark-gluon plasma) phase and the state of cold quark matter. We reconsider the possibility of SQNs as cold dark matter, and find that the formation of black holes in primordial halos could be significantly different from the standard scenario. The SQNs could lead to the formation of black holes with mass as high as 103 Msun, which could be the seeds for the supermassive black holes at redshift z ~ 6.

    • Ttile of Talk (SMFNS2011): Primordial Strange Quark Matter: creation and consequences

      Xiaoyu Lai

    • Abstract: Cosmological QCD phase transition could have abundant consequences on astrophysics. If it is of first-order, strange quark nuggets could form. They could very likely be the candidate of cold quark matter if survived the cooling of the later Universe, although the formation and evolution of these SQNs depend on the physical state of the hot QGP (quark-gluon plasma) and the state of cold quark matter. We revisit the possibility of SQNs as cold dark matter and study the possible consequences. The assembling of SQNs in the center of primordial halos could make it easier to form the supermassive black holes at redshift as high as 6, and the SQNs diffused in the present galaxy could trigger star-quakes of pulsars which result in pulsar-glitches.