Publications (58)191.15 Total impact
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ABSTRACT: Gamma ray bursts have been divided into two classes, longsoft gamma ray burst and shorthard gamma ray burst according to the bimodal distribution in duration time. Due to the harder spectrum and the lack of afterglows of shorthard bursts in optical and radio observations, different progenitors for shorthard bursts and longsoft bursts have been suggested. Based on the Xray afterglow observation and the cumulative redshift distribution of shorthard bursts, Nakar et al. (2006) found that the progenitors of shorthard bursts are consistent with old populations, such as mergers of binary neutron stars. Recently, the existence of two subclasses in longsoft bursts has been suggested after considering multiple characteristics of gammaray bursts, including fluences and the duration time. In this work, we extended the analysis of cumulative redshift distribution to two possible subclasses in LGRBs. We found that two possible subclass GRBs show different redshift distributions, especially for redshifts z > 1. Our results indicate that the accumulative redshift distribution can be used as a tool to constrain the progenitor characteristics of possible subclasses in LGRBs.11/2007;  [Show abstract] [Hide abstract]
ABSTRACT: Recent developments in our description of RHIC and related heavyion 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 Tc. 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 Tc to tightly bound massless states above Tc. This phenomenon may be interpreted in terms of the Bèg–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 Fermiliquid fixed point parameters at the equilibrium density, its implications for “lowmass dileptons” produced in heavyion 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.Physics Reports 01/2007; · 22.93 Impact Factor  [Show abstract] [Hide abstract]
ABSTRACT: In the light of recent observations in which short γray bursts are interpreted as arising from blackhole(BH), neutronstar(NS) or NS–NS mergings we would like to review our research on the evolution of compact binaries, especially those containing NS's. These were carried out with predictions for LIGO in mind, but are directly applicable to short γray bursts in the interpretation above.Most important in our review is that we show that the standard scenario for evolving NS–NS binaries always ends up with a lowmass BH (LMBH), NS binary. Bethe and Brown [1998, Astrophys. J. 506, 780] showed that this fate could be avoided if the two giants in the progenitor binary burned He at the same time, and that in this way the binary could avoid the common envelope evolution of the NS with red giant companion which sends the first born NS into a BH in the standard scenario. The burning of He at the same time requires, for the more massive giants such as the progenitors of the Hulse–Taylor binary NS that the two giants be within 4% of each other in zero age main sequence (ZAMS) mass. Applying this criterion to all binaries results in a factor ∼5 of LMBH–NS binaries as compared with NS–NS binaries.Although this factor is substantially less than the originally claimed factor of 20 which Bethe and Brown (1998) estimated, largely because a careful evolution has been carried through here, our factor 5 is augmented by a factor of ∼8 arising from the higher rate of star formation in the earlier Galaxy from which the BH–NS binaries came from. Furthermore, here we calculate the mergers for shorthard gammaray bursts, whereas Bethe and Brown's factor 20 included a factor of 2 for the higher chirp masses in a BH–NS binary as compared with NS–NS one. In short, we end up with an estimate of factor ∼40 over that calculated with NS–NS binary mergers in our Galaxy alone. Our total rate is estimated to be about one merging of compact objects per year.Our scenario of NS–NS binaries as having been preceded by a double Hestar binary is collecting observational support in terms of the nearly equal NS masses within a given close binary.We review our work on population synthesis of compact binaries, pointing out that it is in excellent agreement with the much more detailed synthesis carried out by Portegies Zwart. This is currently of interest because the recent discovery of the double pulsar has substantially increased the number of binary NS's that will merge gravitationally, giving signals to LIGO. This discovery brings in the low ZAMS mass main sequence progenitors that can evolve into a NS binary, adding importantly to the “visible” binaries that can merge. However it does not affect the factor ≳40 increase, mostly from the much greater number of LMBH–NS binaries, which have only a small probability of being observed before they merge.We develop the phenomenology which suggests that NS's evolve from ZAMS mass ∼10–18M⊙ star, LMBH's from 18–20M⊙, and highmass BH's from 20–30M⊙. These brackets follow from Woosley's 12C(α,γ)16O rate of 170 MeV barns at 300 keV.We discuss the observed violation of our previous maximum NS mass , raising our to 1.7M⊙ and comment on how our scenario would change if the maximum NS mass is greater than 1.7M⊙.Physics Reports 01/2007; · 22.93 Impact Factor  [Show abstract] [Hide abstract]
ABSTRACT: Recent developments in our description of RHIC and related heavyion 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 HaradaYamawaki's vector manifestation structure and BrownRho 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 BegShei 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 BrownRho scaling and Landau Fermiliquid fixed point parameters at the equilibrium density, its implications for "lowmass dileptons" produced in heavyion 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 BrownRho scaling, and the generic feature of dropping masses at the RGE fixed points in generalized hidden local symmetry theories.09/2006; 
Article: Vector manifestation of hidden local symmetry, hadronic freedom, and the STAR ρ^{0}/π^{} ratio
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ABSTRACT: The vector manifestation (VM) fixedpoint scenario found in the HaradaYamawaki hidden local symmetry effective theory makes a striking prediction that as the fireball expands and cools from Tc down toward the freezeout temperature Tfreezeout in heavyion collisions, what we refer to as “hadronic freedom” sets in which hadrons do not interact or barely interact. We suggest that this scenario is testable at the BNL relativistic heavy in collider, and as a specific example, we provide an astonishingly simple prediction in terms of the V.M for the ρ0/π ratio measured in peripheral collisions. We suggest that this hadronic freedom has already been observed in the STAR peripheral collisions, in which the ρ0 mesons were reconstructed by following their pion decay products back to the vertex where they are formed. In this scenario, the measured ρ0/π ratio can be reproduced in these special circumstances only because the “flash temperature” Tflash at which the ρ mesons go onshell is equal to the freezeout temperature. In more central collisions with lower freezeout temperatures, the rescattering of the pions is expected to destroy the possibility of this reconstruction.Physical Review C 08/2006; 74(2). · 3.72 Impact Factor  [Show abstract] [Hide abstract]
ABSTRACT: Building on, and extending, the result of a higherorder inmedium chiral perturbation theory combined with renormalization group arguments and a variety of observations of the vector manifestation of HaradaYamawaki hidden local symmetry theory, we obtain a surprisingly simple description of kaon condensation by fluctuating around the "vector manifestation" fixed point identified to be the chiral restoration point. Our development establishes that strangeness condensation takes place at approximately 3n0 where n0 is nuclear matter density. This result depends only on the renormalizationgroup (RG) behavior of the vector interactions, other effects involved in fluctuating about the bare vacuum in so many previous calculations being irrelevant in the RG about the fixed point. Our results have major effects on the collapse of neutron stars into black holes.Physical Review Letters 03/2006; 96(6):062303. · 7.73 Impact Factor  Hans Bethe and his Physics. 01/2006;
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ABSTRACT: We investigate the Delta S = 0 effective chiral Lagrangian from the instanton vacuum. Based on the Delta S = 0 effective weak Hamiltonian from the operator product expansion and renormalization group equations, we derive the strangenessconserving effective weak chiral Lagrangian from the instanton vacuum to order {{mathcal{O}}}(p^2) and the nexttoleading order in the 1/ N c expansion at the quark level. We find that the quark condensate and a dynamical term which arise from the QCD and electroweak penguin operators appear in the nexttoleading order in the 1/ N c expansion for the Delta S = 0 effective weak chiral Lagrangian, while they are in the leading order terms in the Delta S = 1 case. Three different types of form factors are employed and we find that the dependence on the different choices of the form factor is rather insensitive. The lowenergy constants of the GasserLeutwyler type are determined and discussed in the chiral limit.European Physical Journal C 01/2006; 45:451457. · 5.25 Impact Factor  [Show abstract] [Hide abstract]
ABSTRACT: 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 (Lattice Gauge Simulation) colorsinglet interaction computed for heavy quarks in a modeldependent way by including the Ampére 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 π, σ, ρ and A1 excitations, 32 degrees of freedom in all, go to zero (in the chiral limit) as T→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 bound states, which we interpret as our chirally restored mesons, for T>Tc.Nuclear Physics A 12/2005; · 2.50 Impact Factor  [Show abstract] [Hide abstract]
ABSTRACT: 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 blackhole neutron star binaries are 10 times more dominant than double neutron star binaries. As a result, blackhole, neutron star binaries can increase the LIGO detection rate by a factor 20.11/2005; 
Article: The Ideal Liquid Discovered by RHIC, Infrared Slavery Above and Hadronic Freedom Below $T_c$
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ABSTRACT: 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 quarkantiquark pairs forming chirally restored mesons of the quantum numbers of the $\pi, S, \rho$ 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 quarkantiquark 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.08/2005;  [Show abstract] [Hide abstract]
ABSTRACT: The hidden local symmetry effective theory, Wilsonian matched to QCD at a matching scale near the chiral scale $\sim 4\pi f_\pi$ as formulated by Harada and Yamawaki, presents a scenario drastically different from the standard scenario of heavyion collisions in that as the temperature approaches the critical temperature $T_c$ of chiral restoration from below, the mass of the vector mesons and their widths go to zero in the chiral limit or nearly zero otherwise, proportionally to some power of the quark condensate at what is called "vector manifestation (VM) fixed point". This scenario makes a striking prediction that as the fireball expands and cools from $T_c$ down toward the freezeout temperature $T_{freezeout}$ in heavy ion collisions, what we call "hadronic freedom" sets in in which hadrons do not interact or barely interact. We suggest that this scenario is testable at RHIC and as a specific example, we provide an astonishingly simple explanation in terms of the vector manifestation suitably extended to include axialvector mesons for the anomalously large $\rho^0/\pi^$ ratio measured in peripheral collisions by STAR. Comment: 4 pages, no figures07/2005; 
Article: Relation of Strangeness Nuggets to Strangeness Condensation and the Maximum Mass of Neutron Stars
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ABSTRACT: Combining the recent experimental indications of density dependence in the pion decay constant $f_\pi^\star$ and the $\omega$ meson mass $m_\omega^\star$ 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 neutronstar matter. We suggest that this relation assures kaon condensation at a density $\sim$ three times nuclear matter density which supports the BrownBethe 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.05/2005;  [Show abstract] [Hide abstract]
ABSTRACT: We consider the strangenessconserving effective weak chiral Lagrangian based on the nonlocal chiral quark model from the instanton vacuum. We incorporate the effect of the strong interaction by the gluon into the effective Lagrangian. The effect of the Wilson coefficients on the weak pionnucleon coupling constant is discussed briefly.12/2004: pages 105105;  [Show abstract] [Hide abstract]
ABSTRACT: The main objective of this work is to explore the evolution in the structure of the quarkantiquark bound states in going down in the chirally restored phase from the socalled ``zero binding points'' Tzb to the full (unquenched) QCD critical temperature Tc at which the NambuGoldstone and WignerWeyl modes meet. In doing this, we adopt the idea recently introduced by Shuryak and Zahed for charmed c¯c, lightquark q¯q mesons π,σ,ρ,A1 and gluons that at Tzb, the quarkantiquark scattering length goes through ∞ 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 instantonantiinstanton molecules. The spinspin forces turned out to be small. While near Tzb all mesons are largesize nonrelativistic objects bound by Coulomb attraction, near Tc they get much more tightly bound, with manybody 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 nearlocal fourFermi interactions induced by the instanton molecules play an increasingly more important role as the temperature moves downward toward Tc.Nuclear Physics A 07/2004; 740:171194. · 2.50 Impact Factor  [Show abstract] [Hide abstract]
ABSTRACT: In the hadronic sector of relativistic heavy ion physics, the ρ⇆2π reaction is the strongest one, strong enough to equilibrate the ρ with the pions throughout the region from chemical freezeout to thermal freezeout when freeparticle interactions (with no mediumdependent effects) are employed. Above the chiral restoration temperature, only ρ's and π's are present, in that the chirally restored A1 is equivalent to the ρ and the mesons have an SU(4) symmetry, with no dependence on isospin and negligible dependence on spin. In the same sense the σ and π are “equivalent” scalars. Thus the chirally restored ρ⇆2π exhaust the interspecies transitions. We evaluate this reaction at Tc and find it to be much larger than below Tc, certainly strong enough to equilibrate the chirally restored mesons just above Tc. When emitted just below Tc the mesons remain in the Tc+ε freezeout distribution, at least in the chiral limit because of the Harada–Yamawaki “vector manifestation” that requires that mesonic coupling constants go to zero (in the chiral limit) as T goes to Tc from below. Our estimates in the chiral limit give deviations in some particle ratios from the standard scenario (of equilibrium in the hadronic sector just below Tc) of about double those indicated experimentally. This may be due to the neglect of explicit chiral symmetry breaking in our estimates. We also show that the instanton molecules present above Tc are the giant multipole vibrations found by Asakawa, Hatsuda and Nakahara and of Wetzorke et al. in lattice gauge calculations. Thus, the matter formed by RHIC can equivalently be called: chirally restored mesons, instanton molecules, or giant collective vibrations. It is a strongly interacting liquid.Nuclear Physics A 05/2004; · 2.50 Impact Factor  [Show abstract] [Hide abstract]
ABSTRACT: We discuss the possibility that the soft Xray transient GRS1915 + 105 evolved from a binary similar to V4641Sgr (XTEJ1819  254) by conservative masstransfer, and estimate the possible masstransfer rates during the evolution. The results indicate that the high masstransfer rates could explain the high luminosities in ultraluminous Xray sources. Although the high masstransfer rates during evolution are accompanied by high luminosities, we find that much of the transferred matter may sweeps accompanying radiation in an adiabatic inflow of superEddington accretion. We suggest that soft Xray transients with evolved companions (initial companion mass > 3 Modot), e.g. GRS 1915 + 105, can be ultraluminous Xray sources if they are seen through their beaming axis.Publications Astronomical Society of Japan 04/2004; · 2.44 Impact Factor  [Show abstract] [Hide abstract]
ABSTRACT: The main objective of this work is to explore the evolution in the structure of the quarkantiquark bound states in going down in the chirally restored phase from the socalled "zero binding points" $T_{zb}$ to the QCD critical temperature $T_c$ at which the NambuGoldstone and WignerWeyl modes meet. In doing this, we adopt the idea recently introduced by Shuryak and Zahed for charmed $\bar c c$, lightquark $\bar q q$ mesons $\pi, \sigma, \rho, A_1$ and gluons that at $T_{zb}$, the quarkantiquark 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 instantonantiinstanton molecules. The spinspin forces turned out to be small. While near $T_{zb}$ all mesons are largesize nonrelativistic objects bound by Coulomb attraction, near $T_c$ they get much more tightly bound, with manybody collective interactions becoming important and making the $\sigma$ and $\pi$ masses approach zero (in the chiral limit). The wave function at the origin grows strongly with binding, and the nearlocal fourFermi interactions induced by the instanton molecules play an increasingly more important role as the temperature moves downward toward $T_c$.03/2004;  [Show abstract] [Hide abstract]
ABSTRACT: We investigate medium modifications of the pentaquark $\Theta^+$ in dense medium, taking into account different parities of the exotic $\Theta^+$ baryon. We find that the chemical potential of the $\Theta^+$ is shifted in a densitydependent way to oneloop order. We also investigated the effect of the scaled nucleon mass in dense medium on the $\Theta^+$ propagator. The results turn out to depend sensitively on the scaled nucleon mass and on the parity of the $\Theta^+$.03/2004;  01/2004;
Publication Stats
847  Citations  
191.15  Total Impact Points  
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Institutions

2014

West Virginia University
 Department of Physics
Morgantown, West Virginia, United States


2003–2014

Pusan National University
 Department of Physics
Tsaulianghai, Busan, South Korea


2008

SUNY Ulster
Kingston, New York, United States


2007

Cornell University
Ithaca, New York, United States


2006

State University of New York
New York City, New York, United States


1994–2001

Seoul National University
 Center for Theoretical Physics
Sŏul, Seoul, South Korea


1996

University of Washington Seattle
 Institute for Nuclear Theory
Seattle, Washington, United States
