The Multifaceted Skyrmion
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arXiv subjects
Gerald E. Brown
Publications and source records attributed to Gerald E. Brown.
Hidden Local Field Theory and Dileptons in Relativistic Heavy Ion Collisions
The notion of "hadronic freedom" is introduced based on the vector manifestation of hidden local symmetry and is used to suggest that the dileptons measured in relativistic heavy-ion collisions do not provide {\em direct} information on the spontaneous breaking of chiral symmetry and hence on the mechanism for mass generation of light-quark hadrons. We give arguments how the dileptons emitted from those vector mesons whose masses are shifted à la Brown-Rho (BR) scaling by the vacuum change in temperature -- as in heavy-ion collisions -- and/or density -- as in cold compressed matter -- could be strongly suppressed in the hadronic free region between the chiral restoration point and the "flash point" at which the vector mesons recover $\gsim 90%$ of their free-space on-shell masses and the full strong coupling strength. It may seem ironical that the very mechanism i.e., the vector manifestation in hidden local symmetry, that is to make the mass drop and modify the spectral function is in turn responsible for the dilepton suppression. A possible falsification of this drastic prediction will be indicated. We also briefly discuss the potential role played by the holographic dimension intrinsic in gravity-gauge duality that provides a unified field theory description of hadrons -- both mesons and baryons -- under extreme conditions. Baryons arise as coherent states of pions and vector mesons of holographic QCD which define the ground state or the "vacuum" on which mesonic excitations could undergo BR scaling.
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A Hidden Local Field Theory Description of Dileptons in Relativistic Heavy Ion Collisions
This paper has been withdrawn by the authors. Some of the arguments developed in the paper are erroneous. They will be rectified in a later publication.
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Supernova 2008D: A Repetition of Supernova 1987A In a Binary
The Supernova 2008D is similar to that of SN 1987A without the H-envelope. Soderberg et al.(2008) reported the serendipitous discovery of the SN2008D at the time of the explosion, accompanied by an X-ray outburst XRF080109. The central remnant, which we believe to be the black-hole (BH) central engine in the Blandford-Znajek mechanism, is estimated, on the basis of the 7% 56Ni production, to have a mass of 1.6-1.8 M_sun. This is not much larger than the upper limit of 1.56 m_sun for the mass of the compact object in SN1987A found by Bethe & Brown (1995); also, on the basis of the 7.5% 56Ni production, they interpreted it as a low-mass BH. Redoing the light curve so as to take into account the absence of convective carbon burning from zero age main sequence 18-24 M_sun and replacing it by carbon shell burning, we see that the remnant in SN2008D must be less massive than in SN 1987A; there of 18 M_sun. Thus, the maximum neutron star mass is 1.5 M_sun. Note that the metallicity of the host galaxy of SN2008D is similar to that of our Galaxy.
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Understanding Dilepton Production in Heavy Ion Collisions by Vector Mesons of Different Varieties
A simple schematic model anchored on the notion of hadronic freedom inferred from hidden local symmetry in the vector manifestation, the infinite tower of vector mesons in holographic QCD and "stickiness" of $ππ$ interactions inferred from dispersion relations is used to describe the dileptons produced in relativistic heavy ion collisions at PHENIX/RHIC. It is shown that due to the near "blindness" of dileptons to Brown-Rho scaling, those dileptons with invariant mass less than $m_ρ=770$ MeV come mostly from pion-composites that we interpret as "transient $ρ$'s."
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Recent Developments on Kaon Condensation and Its Astrophysical Implications
We discuss three different ways to arrive at kaon condensation at n_c = 3 n_0 where n_0 is nuclear matter density: (1) Fluctuating around the n=0 vacuum in chiral perturbation theory, (2) fluctuating around n_VM near the chiral restoration density n_chi where the vector manifestation of hidden local symmetry is reached and (3) fluctuating around the Fermi liquid fixed point at n_0. They all share one common theoretical basis, "hidden local symmetry." We argue that when the critical density n_c < n_chi is reached in a neutron star, the electrons turn into K^- mesons, which go into an S-wave Bose condensate. This reduces the pressure substantially and the neutron star goes into a black hole. Next we develop the argument that the collapse of a neutron star into a black hole takes place for a star of M = 1.5 M_sun. This means that Supernova 1987A had a black hole as result. We also show that two neutron stars in a binary have to be within 4% of each other in mass, for neutron stars sufficiently massive that they escape helium shell burning. For those that are so light that they do have helium shell burning, after a small correction for this they must be within 4% of each other in mass. Observations support the proximity in mass inside of a neutron star binary. The result of strangeness condensation is that there are 5 times more low-mass black-hole, neutron-star binaries than double neutron-star binaries although the former are difficult to observe.
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Late Hadronization and Matter Formed at RHIC: Vector Manifestation, Brown-Rho Scaling and Hadronic Freedom
Recent developments in our description of RHIC and related heavy-ion phenomena in terms of hidden local symmetry theories are reviewed with a focus on the novel nearly massless states in the vicinity of -- both below and above -- the chiral restoration temperature T_c. We present complementary and intuitive ways to understand both Harada-Yamawaki's vector manifestation structure and Brown-Rho scaling -- which are closely related -- in terms of "melting" of soft glues observed in lattice calculations and join the massless modes that arise in the vector manifestation (in the chiral limit) just below T_c to tightly bound massless states above T_c. This phenomenon may be interpreted in terms of the Beg-Shei theorem. It is suggested that hidden local symmetry theories arise naturally in holographic dual QCD from string theory, and a clear understanding of what really happens near the critical point could come from a deeper understanding of the dual bulk theory. Other matters discussed are the relation between Brown-Rho scaling and Landau Fermi-liquid fixed point parameters at the equilibrium density, its implications for "low-mass dileptons" produced in heavy-ion collisions, the reconstruction of vector mesons in peripheral collisions, the pion velocity in the vicinity of the chiral transition point, kaon condensation viewed from the VM fixed point, nuclear physics with Brown-Rho scaling, and the generic feature of dropping masses at the RGE fixed points in generalized hidden local symmetry theories.
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Double Neutron Star Binaries: Implications for LIGO
Double neutrons are especially important because they give most accurate informations on the masses of neutron stars. Observations on double neutron stars show that all masses of the neutron stars are below 1.5$\msun$. Furthermore, two neutron stars in a given double pulsar are nearly equal in mass. With hypercritical accretion, we found that the probability of having companion mass $>1.5\msun$ is larger than 90%, while there is no observations on such systems. We believe that those companions with masses higher than $1.5\msun$ went into black holes, which is consistent with our preferred maximum neutron star mass $M_{NS}^{max} \approx 1.5\msun$ due to the kaon condensation. In this work, we point out that the black-hole neutron star binaries are 10 times more dominant than double neutron star binaries. As a result, black-hole, neutron star binaries can increase the LIGO detection rate by a factor 20.
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The Problem of Mass: Mesonic Bound States Above T_c
We discuss the problem of mass, noting that meson masses decrease with increasing scale as the dynamically generated condensate of "soft glue" is melted (Brown/Rho scaling). We then extend the Bielefeld LGS color singlet interaction computed for heavy quarks in a model-dependent way by including the Ampere law velocity-velocity interaction. Parameterizing the resulting interaction in terms of effective strength of the potential and including screening, we find that the masses of pi, sigma, rho and A1 excitations, 32 degrees of freedom in all, go to zero (in the chiral limit) as T goes to Tc essentially independently of the input quark (thermal) masses in the range of 1-2 GeV, calculated also in Bielefeld. We discuss other LGS which show q-bar q bound states, which we interpret as our chirally restored mesons, for T > Tc.
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The Ideal Liquid Discovered by RHIC, Infrared Slavery Above and Hadronic Freedom Below $T_c$
We construct the nature of the matter found in RHIC when its temperature has dropped down close to, and below, $T_c$. Just above $T_c$ it is composed of extremely strongly bound quark-antiquark pairs forming chirally restored mesons of the quantum numbers of the $π, S, ρ$ and $a_1$ with very small size and zero energy and just below $T_c$, it is composed of mesons of the same quantum numbers with zero mass. We invoke infrared slavery for the former and the vector manifestation (VM) of hidden local symmetry for the latter. As the temperature drops below $T_c$, the strongly bound quark-antiquark pairs are ejected into what is basically a region of "hadronic freedom" in which the interactions are zero. Experimental evidences for this are seen in the STAR data.
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Relation of Strangeness Nuggets to Strangeness Condensation and the Maximum Mass of Neutron Stars
Combining the recent experimental indications of density dependence in the pion decay constant $f_π^\star$ and the $ω$ meson mass $m_ω^\star$ and the discovery of $S^0 (3115)$ and other "strange nuggets" with the vector manifestation of chiral symmetry in hidden local symmetry proposed by Harada and Yamawaki, we show that the mechanism responsible for dense strangeness nuggets can be related to that responsible for kaon condensation in neutron-star matter. We suggest that this relation assures kaon condensation at a density $\sim$ three times nuclear matter density which supports the Brown-Bethe scenario for the $M_{\rm NS}^{max} \simeq 1.5\msun$. This low $M_{\rm NS}^{\rm max}\sim 1.5\msun$ has major consequences in astrophysics, especially for the merging rate of compact stellar objects.
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The \bar q q Bound States and Instanton Molecule at T >~ T_c
The main objective of this work is to explore the evolution in the structure of the quark-anti-quark bound states in going down in the chirally restored phase from the so-called "zero binding points" $T_{zb}$ to the full (unquenched) QCD critical temperature $T_c$ at which the Nambu-Goldstone and Wigner-Weyl modes meet. In doing this, we adopt the idea recently introduced by Shuryak and Zahed for charmed $\bar c c$, light-quark $\bar q q$ mesons $π, σ, ρ, A_1$ and gluons that at $T_{zb}$, the quark-anti-quark scattering length goes through $\infty$ at which conformal invariance is restored, thereby transforming the matter into a near perfect fluid behaving hydrodynamically, as found at RHIC. We show that the binding of these states is accomplished by the combination of (i) the color Coulomb interaction, (ii) the relativistic effects, and (iii) the interaction induced by the instanton-anti-instanton molecules. The spin-spin forces turned out to be small. While near $T_{zb}$ all mesons are large-size nonrelativistic objects bound by Coulomb attraction, near $T_c$ they get much more tightly bound, with many-body collective interactions becoming important and making the $σ$ and $π$ masses approach zero (in the chiral limit). The wave function at the origin grows strongly with binding, and the near-local four-Fermi interactions induced by the instanton molecules play an increasingly more important role as the temperature moves downward toward $T_c$.
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A new state of matter at high temperature as "sticky molasses"
The main objective of this work is to explore the evolution in the structure of the quark-antiquark bound states in going down in the chirally restored phase from the so-called "zero binding points" $T_{zb}$ to the QCD critical temperature $T_c$ at which the Nambu-Goldstone and Wigner-Weyl modes meet. In doing this, we adopt the idea recently introduced by Shuryak and Zahed for charmed $\bar c c$, light-quark $\bar q q$ mesons $π, σ, ρ, A_1$ and gluons that at $T_{zb}$, the quark-antiquark scattering length goes through $\infty$ at which conformal invariance is restored, thereby transforming the matter into a near perfect fluid behaving hydrodynamically, as found at RHIC. We name this new state of matter as "sticky molasses". We show that the binding of these states is accomplished by the combination of (i) the color Coulomb interaction, (ii) the relativistic effects, and (iii) the interaction induced by the instanton-anti-instanton molecules. The spin-spin forces turned out to be small. While near $T_{zb}$ all mesons are large-size nonrelativistic objects bound by Coulomb attraction, near $T_c$ they get much more tightly bound, with many-body collective interactions becoming important and making the $σ$ and $π$ masses approach zero (in the chiral limit). The wave function at the origin grows strongly with binding, and the near-local four-Fermi interactions induced by the instanton molecules play an increasingly more important role as the temperature moves downward toward $T_c$.
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The Case for Case C Mass Transfer in the Galactic Evolution of Black Hole Binaries
Earlier works, which we review, have shown that if the Fe core in a presupernova star is to be sufficiently massive to collapse into a black hole, earlier in the evolution of the star the He core must be covered (clothed) by a hydrogen envelope during He core burning and removed only following this, in, e.g. common envelope evolution. This is classified as Case C mass transfer. These previous arguments were based chiefly on stellar evolution, especially depending on the way in which 12C burned. In this work we argue for Case C mass transfer on the basis of binary evolution. The giant progenitor of the black hole will have a large radius 1000 Rsun at the end of its supergiant stage. Its lifetime at that point will be short, about 1000 yrs, so it will not expand much further. Thus, the initial giant radius for Case C mass transfer will be constrained to a narrow band about 1000 Rsun. This has the consequence that the final separation a_f following common envelope evolution will depend nearly linearly on the mass of the companion m_d which becomes the donor after the He core of the giant has collapsed into the black hole. The separation at which this collapse takes place is essentially a_f, because of the rapid evolution of the giant. (In at least two binaries the black hole donor separation has been substantially increased because of mass loss in the black hole formation. These can be reconstructed from the amount of mass deposited on the donor in this mass loss.) We show that the reconstructed preexplosion separations of the black hole binaries fit well the linear relationship.
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Renormalization group approach to neutron matter: quasiparticle interactions, superfluid gaps and the equation of state
Renormalization group methods can be applied to the nuclear many-body problem using the approach proposed by Shankar. We start with the two-body low momentum interaction V_{low k} and use the RG flow from the particle-hole channels to calculate the full scattering amplitude in the vicinity of the Fermi surface. This is a new straightforward approach to the many-body problem which is applicable also to condensed matter systems without long-range interactions, such as liquid 3He. We derive the one-loop renormalization group equations for the quasiparticle interaction and the scattering amplitude at zero temperature. The RG presents an elegant method to maintain all momentum scales and preserve the antisymmetry of the scattering amplitude. As a first application we solve the RG equations for neutron matter. The resulting quasiparticle interaction includes effects due to the polarization of the medium, the so-called induced interaction of Babu and Brown. We present results for the Fermi liquid parameters, the equation of state of neutron matter and the 1S0 superfluid pairing gap.
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On the Theory of Gamma Ray Bursts and Hypernovae: The Black Hole Soft X-ray Transient Sources
We show that a common evolutionary history can produce the black hole binaries in the Galaxy in which the black holes have masses of ~ 5-10 M_sun. In with low-mass, <~ 2.5 M_sun, ZAMS (zero age main sequence) companions, the latter remain in main sequence during the active stage of soft X-ray transients (SXTs), most of them being of K or M classification. In two intermediate cases, IL Lupi and Nova Scorpii with ZAMS ~ 2.5 M_sun companions the orbits are greatly widened because of large mass loss in the explosion forming the black hole, and whereas these companions are in late main sequence evolution, they are close to evolving. Binaries with companion ZAMS masses >~ 3 M_sun are initially "silent" until the companion begins evolving across the Herzsprung gap. We provide evidence that the narrower, shorter period binaries, with companions now in main sequence, are fossil remnants of gamma ray bursters (GRBs). We also show that the GRB is generally accompanied by a hypernova explosion (a very energetic supernova explosion). We further show that the binaries with evolved companions are good models for some of the ultraluminous X-ray sources (ULXs) recently seen by Chandra in other galaxies. The great regularity in our evolutionary history, especially the fact that most of the companions of ZAMS mass <~ 2.5 M_sun remain in main sequences as K or M stars can be explained by the mass loss in common envelope evolution to be Case C; i.g., to occur only after core He burning has finished. Since our argument for Case C mass transfer is not generally understood in the community, we add an appendix, showing that with certain assumptions which we outline we can reproduce the regularities in the evolution of black hole binaries by Case C mass transfer.
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Broad Band Equilibration of Strangeness
We develop the "broad band equilibration" scenario for kaon productions at GSI energies with in-medium effects.
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