The phase transition of hadronic to quark matter at high baryon and isospin density is analyzed. Relativistic mean field models are used to describe hadronic matter, and the MIT bag model is adopted for quark matter. The boundaries of the mixed phase and the related critical points for symmetric and asymmetric matter are obtained. Due to the different symmetry term in the two phases, isospin effects appear to be rather significant. With increasing isospin asymmetry the binodal transition line of the (T,ρ_B) diagram is lowered to a region accessible through heavy ion collisions in the energy range of the new planned facilities, e.g. the FAIR/NICA projects. Some observable effects are suggested, in particular an "Isospin Distillation" mechanism with a more isospin asymmetric quark phase, to be seen in charged meson yield ratios, and an onset of quark number scaling of the meson/baryon elliptic flows. The presented isospin effects on the mixed phase appear to be robust with respect to even large variations of the poorly known symmetry term at high baryon density in the hadron phase. The dependence of the results on a suitable treatment of isospin contributions in effective QCD Lagrangian approaches, at the level of explicit isovector parts and/or quark condensates, is finally discussed.
In this paper is investigated the influence of net baryon density on baryon and meson yields in relativistic nucleus-nucleus collisions, based on the recombination model for hadronization. Unitarity condition is used as a constraint on the model. Three cases with different assumptions on the expansion of partonic system are considered and the baryon to meson ratio is calculated for those situations.
Phi meson-baryon cross sections, estimated within a one-boson-exchange model, serve as input for a calculation of the collision rates in hot hadronic matter. We find that the width of the ϕmeson is modified through collisions with baryons by 1-10 MeV at 160 MeV temperature depending on the baryon fugacity. Thermalization of the ϕin high energy heavy ion collisions is discussed.
Hadron--quark mixed phase is expected in a wide region of the inner structure of hybrid stars. However, we show that the hadron--quark mixed phase should be restricted to a narrower region to because of the charge screening effect. The narrow region of the mixed phase seems to explain physical phenomena of neutron stars such as the strong magnetic field and glitch phenomena, and it would give a new cooling curve for the neutron star.
Starting with the Strongly Correlated Quark Model of a hadron structure, SCQM, we demonstrate how the properties of mesons and baryons are modified in a hot and dense nuclear environment. These in-medium modifications can lead to the observable effects in heavy ion collisions, such as enhancement of strangeness and dropping vector meson masses.
The drag and diffusion coefficients of heavy baryons ($Λ_c$ and $Λ_b$) in the hadronic phase created in the latter stage of the heavy-ion collisions at RHIC and LHC energies have been evaluated recently. In this work we compute some experimental observables, such as the nuclear suppression factor $R_{AA}$ and the elliptic flow $v_2$ of heavy baryons at RHIC and LHC energies, highlighting the role of the hadronic phase contribution to these observables, which are going to be measured at Run 3 of LHC. For the time evolution of the heavy quarks in the QGP and heavy baryons in the hadronic phase w…
Baryon-strangeness correlations ($C_{BS}$) are studied with a hadron/string transport approach (UrQMD) and a dynamical quark recombination model (quark molecular dynamics, qMD) for various energies from $E_{lab}=4A$ GeV to $\sqrt{s_{NN}}=200$ GeV. As expected, we find that the hadron/string dynamics shows correlations similar to a simple hadron gas. In case of the quark molecular dynamics, we find that initially the $C_{BS}$ correlation is that of a weakly interacting QGP but changes in the process of hadronization also to the value for a hadron gas. Therefore, we conclude that the hadronizati…
The Nijmegen soft-core model for the pseudoscalar-meson baryon interaction is derived, analogous to the Nijmegen NN and YN models. The interaction Hamiltonians are defined and the resulting amplitudes for one-meson-exchange and one-baryon-exchange in momentum space are given for the general mass case. The partial wave projection is carried through and explicit expressions for the momentum space partial wave meson-baryon potentials are presented.
In this talk I look into three different topics, addressing first the possibility that the $Θ^+$ is a bound state of $K πN$, exploiting the results of this study to find out the contribution of two meson and one baryon components in the baryon antidecuplet and in the third place I present results on a new resonant exotic baryonic state which appears as dynamically generated by the Weinberg Tomozawa $ΔK$ interaction.
Baryon-strangeness correlation (C$_{BS}$) has been investigated with a multi-phase transport model (AMPT) in $^{197}$Au + $^{197}$Au collisions at $\sqrt{s_{NN}}$ = 200 GeV. The centrality dependence of C$_{BS}$ is presented within the model, from partonic phase to hadronic matter. We find that the system still reserve partial predicted signatures of C$_{BS}$ after parton coalescence. But after hadronic rescattering, the predicted signatures will be obliterated completely. So it seems that both coalescence hadronization process and hadronic rescattering are responsible for the disappearance of…
Relativistic constituent quark models generally describe three-quark systems with particular interactions. The corresponding invariant mass eigenvalue spectra and pertinent eigenstates should exhibit the multiplet structure anticipated for baryon resonances. Taking into account the flavour content, spin structure, and spatial distribution of the baryon wave functions together with mass relations of the eigenvalues and decay properties of the eigenstates, we can link the theoretical mass eigenstates with the experimentally measured resonances. The resulting classification of baryon resonances d…
We point out that the variance of net-baryon distribution normalized by the Skellam distribution baseline, $κ_2[B-\bar{B}]/\langle B+\bar{B}\rangle$, is sensitive to the possible modification of (anti)baryon yields due to $B\bar{B}$ annihilation in the hadronic phase. The corresponding measurements can thus place stringent limits on the magnitude of the $B\bar{B}$ annihilation and its inverse reaction. We perform Monte Carlo simulations of the hadronic phase in Pb-Pb collisions at the LHC via the recently developed subensemble sampler + UrQMD afterburner and show that the effect survives in ne…
Exclusive vector meson photoproduction associated with a leading baryon ($B = n, Δ^+, Δ^0$) in $pp$ and $pA$ collisions at RHIC and LHC energies is investigated using the color dipole formalism and taking into account nonlinear effects in the QCD dynamics. In particular, we compute the cross sections for $ρ$, $ϕ$ and $J/Ψ$ production together with a $Δ$ and compare the predictions with those obtained for a leading neutron. Our results show that the $V + Δ$ cross section is almost 30 % of the $V + n$ one. Our results also show that a future experimental analysis of these processes is, in princi…
The masses of baryons containing a heavy quark are calculated to next-to-leading order in partially quenched heavy hadron chiral perturbation theory. Calculations are performed for three light flavors in the isospin limit and additionally for two light non-degenerate flavors. The results presented are necessary for extrapolating lattice QCD and partially quenched lattice QCD calculations of the heavy hadron masses.
A hybrid (hydrodynamics + hadronic transport) theoretical framework is assembled to model the bulk dynamics of relativistic heavy-ion collisions at energies accessible in the Beam Energy Scan (BES) program at the Relativistic Heavy-Ion Collider (RHIC) and the NA61/SHINE experiment at CERN. The system's energy-momentum tensor and net baryon current are evolved according to relativistic hydrodynamics with finite shear viscosity and non-zero net baryon diffusion. Our hydrodynamic description is matched to a hadronic transport model in the dilute region. With this fully integrated theoretical fram…
Although strange quarks are produced in $s\bar{s}$ pairs, the ratio of $Ω^{-}$ to ${\barΩ}^{+}$ is greater than one in heavy-ion collisions at lower RHIC energies. Thus the produced $Ω$ hyperons must carry net baryon quantum numbers from the colliding nuclei. We present results of $K$-$Ω$ correlations from AMPT model simulations of Au+Au collisions at $\sqrt{s_{NN}}$ = 14.6 GeV, to probe dynamics for baryon number transport to mid-rapidities at this beam energy. We use both the default and string-melting versions to illustrate how hadronization schemes of quark coalescence and string fragmenta…
The equation of state of a baryon-symmetric hadronic matter with hard-sphere interactions is studied. It is assumed that mesons are point-like, but baryons and antibaryons have the same hard-core radius rB. Three possibilities are considered: 1) the baryon-baryon and antibaryon-baryon interactions are the same; 2) baryons do not interact with antibaryons; 3) the baryon-antibaryon and meson-(anti)baryon interactions are negligible. By choosing the parameter rB=0.3-0.6 fm, we calculate the nucleon to pion ratio as a function of temperature and perform the fit of hadron yields measured in central…
Relativistic heavy ion collisions are studied assuming that particles can be described by a hadron gas in thermal and chemical equilibrium. The exact conservation of baryon number, strangeness and charge are explicitly taken into account. For heavy ions the effect arising from the neutron surplus becomes important and leads to a substantial increase in e.g. the $π^-/π^+$ ratio. A method is developed which is very well suited for the study of small systems.
We investigate the effects of finite baryon chemical potential on the transport properties of a hadron resonance gas. We find that a hadron resonance gas with large baryon number density is closer to the ideal fluid limit than the corresponding gas with zero baryon number. This suggests that the system created at the Relativistic Heavy Ion Collider (RHIC) at lower collision energies may behave as a fluid, with an effective fluidity close to the one found at RHIC's highest energy near phase transition. This might explain why the differential elliptic flow coefficient measured at lower collision…
We evaluate the factor $κ$ appearing in Langer's expression for the nucleation rate extended to the case of hadron bubbles forming in zero baryon number cooled quark-gluon plasma. We consider both the absence and presence of viscosity and show that viscous effects introduce only small changes in the value of $κ$
Using hadronic Lagrangians that include the interaction of pentaquark $Θ^+$ baryon with $K$ and $N$, we evaluate the cross sections for its production from meson-proton, proton-proton, and photon-proton reactions near threshold. With empirical coupling constants and form factors, the predicted cross sections are about 1.5 mb in kaon-proton reactions, 0.1 mb in rho-nucleon reactions, 0.05 mb in pion-nucleon reactions, 20 $μ$b in proton-proton reactions, and 40 nb in photon-proton reactions.
The centrality dependence of the $p/π$ ratio measured by the ALICE Collaboration in 5.02 TeV Pb-Pb collisions indicates a statistically significant suppression with the increase of the charged particle multiplicity once the centrality-correlated part of the systematic uncertainty is eliminated from the data. We argue that this behavior can be attributed to baryon annihilation in the hadronic phase. By implementing the $B\bar{B} \leftrightarrow 5π$ reaction within a generalized partial chemical equilibrium framework, we estimate the annihilation freeze-out temperature at different centralities,…
With the HIJING/BBbar v2.0 heavy ion event generator, we explore the phenomenological consequences of several high parton density dynamical effects predicted in central Pb+Pb collisions at the Large Hadron Collider (LHC) energies. These include (1) jet quenching due to parton energy loss (dE/dx), (2) strangeness and hyperon enhancement due to strong longitudinal color field (SCF), and (3) enhancement of baryon-to-meson ratios due to baryon-anti-baryon junctions (JJbar) loops and SCF effects. The saturation/minijet cutoff scale p0(s)and effective string tension kappa(s,A) are constrained by our…
We develop a flexible quasiparticle theory of transport coefficients of hot hadronic matter at finite baryon density. We begin with a hadronic quasiparticle model which includes a scalar and a vector mean field. Quasiparticle energies and the mean fields depend on temperature and baryon chemical potential. Starting with the quasiparticle dispersion relation, we derive the Boltzmann equation and use the Chapman-Enskog expansion to derive formulas for the shear and bulk viscosities and thermal conductivity. We obtain both relaxation time approximation formulas and more general integral equations…
We describe a calculation of the spectrum of strange and nonstrange hadrons that simultaneously correlates the dressed-quark-core masses of meson and baryon ground- and excited-states within a single framework. The foundation for this analysis is a symmetry-preserving Dyson-Schwinger equation treatment of a vector-vector contact interaction. Our results exemplify and highlight the deep impact of dynamical chiral symmetry breaking on the hadron spectrum: an accurate description of the meson spectrum entails a similarly successful prediction of the spectrum of baryons, including those with stran…
We study the phase diagram of a hadronic chiral flavor-SU(3) model. Heavy baryon resonances can induce a phase structure that matches current results from lattice-QCD calculations at finite temperature and baryon density. Furthermore, we determine trajectories of constant entropy per net baryon in the phase diagram.
A mean-field potential version of the Ultra-relativistic Quantum Molecular Dynamics (UrQMD) model is used to investigate the production of strange baryons, especially the $Λ$s and $\overlineΛ$s, from heavy ion collisions at SPS energies. It is found that, with the consideration of both formed and pre-formed hadron potentials in UrQMD, the transverse mass and longitudinal rapidity distributions of experimental data of both $Λ$s and $\overlineΛ$s can be quantitatively explained fairly well. Our investigation also shows that both the production mechanism and the rescattering process of hadrons pl…
We evaluate thermodynamical quantities and transport coefficients of a dense and hot hadronic matter based on an event generator URASiMA (Ultra-Relativistic AA collision Simulator based on Multiple Scattering Algorithm). The statistical ensembles in equilibrium with fixed temperature and chemical potential are generated by imposing periodic boundary condition to the simulation of URASiMA, where energy density and baryon number density is conserved. Achievement of the thermal equilibrium and the chemical equilibrium are confirmed by the common value of slope parameter in the energy distribution…
The quantum mechanical Beth-Uhlenbeck (BU) approach for repulsive hard-core interactions between baryons is applied to the thermodynamics of a hadron gas. The second virial coefficient $a_2$ -- the "excluded volume" parameter -- calculated within the BU approach is found to be temperature dependent, and it differs dramatically from the classical excluded volume (EV) model result. At temperatures $T =100-200$ MeV, the widely used classical EV model underestimates the EV parameter for nucleons at a given value of the nucleon hard-core radius by large factors of 3-4. Previous studies, which emplo…
The description of baryon resonance decays represents a major challenge of strong interaction physics. We will report on a relativistic approach to mesonic decays of light and strange baryon resonances within constituent quark models. The calculations are performed in the point-form of relativistic quantum mechanics, specifically focussing on the strange sector. It is found that the relativistic predictions generally underestimate the experimental data. The nonrelativistic approximation of the approach leads to the decay operator of the elementary emission model. It is seen that the nonrelativ…
This work is a continuation in our series of papers, that addresses quark models of hadronic structure on the light front. The chief focus of this paper is the quantum-mechanical solution of the three-quark model Hamiltonian, describing baryons. In Jacobi coordinates, we use a harmonic oscillator basis for the transverse directions. For the longitudinal momentum fractions $x_i$, the pertinent basis follows from quantum mechanics in a "triangular cup" potential, which we solve exactly. We calculate the masses and light front wave functions for the flavor symmetric $\frac 32^+$ baryons $bbb,ccc,…
The algebraic treatment of baryons is extended to strange resonances. Within this framework we study a collective string-like model in which the radial excitations are interpreted as rotations and vibrations of the strings. We derive a mass formula and closed expressions for strong and electromagnetic decay widths and use these to analyze the available experimental data.
We analyze the light-flavor particle mass spectra and show that in the region up to ~1.8GeV the Hagedorn temperature for baryons is about 30% smaller than for mesons, reflecting the fact that the number of baryon states grows more rapidly with the mass. We also show that the spectra are well reproduced in a model where hadrons are compound objects of quanta, whose available number increases with mass. The rapid growth of number of hadronic states is a combinatorial effect. We also point out that an upper limit on the excitation energy of these quanta results in a maximum number of hadron state…
The most general spin structures of the spin-1/2 baryon and spinless meson production operator for both photon and nucleon induced reactions are derived from the partial-wave expansions of these reaction amplitudes. The present method provides the coefficients multiplying each spin operator in terms of the partial-wave matrix elements. The result should be useful in studies of these reactions based on partial-wave analyses, especially, when spin observables are considered.
We investigate the density fluctuations induced by hadronic interactions at low temperatures and large chemical potentials after the hadronization of quark-gluon plasma~(QGP). We analyze the structures of net-baryon number kurtosis and skewness and elaborate on their relations with the nuclear liquid-gas~(LG) phase transition and hadronic interactions above the critical temperature. Combining with the relevant experimental projects at RHIC/NICA/FAIR/J-PARC/HIAF with collision energies from $200\,$GeV to $1.8\,$GeV, we propose a double-peak structure of kurtosis (skewness) as a function of coll…
The baryon distribution is studied by using a parton cascade model which is based on pQCD incorporating hard partonic scattering and dynamical hadronization scheme. In order to study baryon distribution,baryonic cluster formation is newly implemented as well as hadronic higher resonance states from parton/beam cluster decay. The net baryon number and charged hadron distributions are calculated with different $K$-factors in which parameters are fixed by elementary $p\bar p$ data at $E_{c.m.}=200$ GeV. It is found that baryon stopping behavior at SPS and RHIC energies are not consequence of hard…
We study the formation of baryons as composed of quarks and diquarks in hot and dense hadronic matter in a Nambu--Jona-Lasinio (NJL)--type model. We first solve the Dyson-Schwinger equation for the diquark propagator and then use this to solve the Dyson-Schwinger equation for the baryon propagator. We find that stable baryon resonances exist only in the phase of broken chiral symmetry. In the chirally symmetric phase, we do not find a pole in the baryon propagator. In the color-superconducting phase, there is a pole, but is has a large decay width. The diquark does not need to be stable in ord…
Baryon annihilations during the hadronic stage of heavy-ion collisions affects final-state baryon and antibaryon yields and final-state correlations of baryons and antibaryons. Understanding annihilation is important for addressing questions about the chemistry at the beginning of the hadronic stage, and for interpreting charge-balance correlations involving baryons. Here, charge balance functions, using protons and antiprotons binned by relative momentum, rapidity and azimuthal angle, are shown to clarify the amount of annihilation in the hadronic stage. This enables a more accurate extractio…
The hadron production in relativistic heavy ion collisions is well described by the quark combination model. The mixed ratios for various hadrons and the transverse momentum spectra for long-life hadrons are predicted and agree with recent RHIC data. The production rates for the pentaquarks $Θ^+$, $Θ^{*++}$ and the di-baryon $(ΩΩ)_{0^{+}}$ are estimated, neglecting the effect from the transition amplitude for constituent quarks to form an exotic state.
We discuss baryon resonances which are dynamically generated in hadron dynamics based on chiral coupled channels approach. With the dynamical description of the baryon resonance, we discuss the origin of the resonance pole, finding that for the description of N(1535) some other components than meson and baryon are necessary. Since the chiral unitary model provides a microscopic description in terms of constituent hadrons, it is straightforward to calculate transition amplitudes and form factors of resonances without introducing further parameters. Finally we briefly discuss few-body nuclear ka…
We introduce an algebraic framework for the description of baryons. Within this framework we study a collective string-like model and show that this model gives a good overall description of the presently available data. We discuss in particular masses and electromagnetic couplings, including the transition form factors that can be measured at new electron facilities.
Possibility of kaon-condensed phase in hyperon-mixed matter is considered on the basis of chiral symmetry for kaon-baryon and kaon-kaon interactions, being combined with the relativistic mean-field theory for two-body baryon interaction. In addition, universal three-baryon repulsive force in the string-junction model and phenomenological three-nucleon attractive force are introduced. It is shown that softening of the equation of state stemming from both kaon condensation and mixing of hyperons is compensated with the repulsive effect of the three-baryon force and the relativistic effect for tw…
We discuss the role of repulsive baryon-baryon interactions in a hadron gas using relativistic virial expansion and repulsive mean field approaches. The fluctuations of the baryon number as well as strangeness-baryon correlations are calculated in the hadron resonance gas with repulsive interactions and compared with the recent lattice QCD results. In particular, we calculate the difference between the second and fourth order fluctuations and correlations of baryon number and strangeness, that have been proposed as probes of deconfinement. We show that for not too high temperatures these diffe…
The electromagnetic properties of baryons containing a heavy quark are calculated at next-to-leading order in partially quenched heavy hadron chiral perturbation theory. Calculations are performed for three light flavors in the isospin limit and additionally for two light non-degenerate flavors. We use partially-quenched charge matrices that are easy to implement on the lattice. The results presented are necessary for the light quark mass extrapolation and zero-momentum extrapolation of lattice QCD and partially quenched lattice QCD calculations of heavy hadron electromagnetic properties. Addi…
We demonstrate that both quark-gluon plasma (QGP) and hadronic gas (HG) models of the central fireball created in S -> W collisions at 200 GeV A are possible sources of the recently observed strange (anti-) baryons. From the theoretical point of view, the HG interpretation we attempt remains more obscure because of the high fireball temperature required. The thermal properties of the fireball as determined by the particle ratios, are natural for the QGP state. We show that the total particle multiplicity emerging from the central rapidity region allows to distinguish between the two scenarios.
The interaction of spatially extended heavy hadrons is investigated in the framework of lattice QCD with dynamical quarks. In addition to the baryon-baryon potential results for the baryon-antibaryon and for the meson-meson system are presented. It is shown that the expected dipole forces have a very short range and that sea quarks play a minor important role.
We present results for masses of excited baryons from a quenched calculation with Chirally Improved quarks at pion masses down to 350 MeV. Our analysis of the correlators is based on the variational method. In order to provide a large basis set for spanning the physical states, we use interpolators with different Dirac structures and Jacobi smeared quark sources of different width. Our spectroscopy results for a wide range of ground state and excited baryons are discussed.
In these lectures I make an introduction to chiral unitary theory applied to the meson baryon interaction and show how several well known resonances are dynamically generated, and others are predicted. Two very recent experiments are analyzed, one of them showing the existence of two $Λ(1405)$ states and the other one providing support for the $Λ(1520)$ resonance as a quasibound state of $Σ(1385) π$. The use of chiral Lagrangians to account for the hadronic interaction at the elementary level introduces a new approach to deal with the modification of meson and baryon properties in a nuclear me…
We present a path-integral hadronization for doubly heavy baryons. The two heavy quarks in the baryon are approximated as a scalar or axial-vector diquark described by a heavy diquark effective theory. The gluon dynamics are represented by a NJL-Model interaction for the heavy diquarks and light quarks, which leads to an effective action of the baryon fields after the quark and diquark fields are integrated out. This effective action for doubly heavy baryon includes the electromagnetic and electroweak interactions, as well as the interaction with light mesons. We also verify the Ward-Takahashi…
Quark-hadron matter at finite temperature and density is studied using a two-flavor, color SU(2) (P)NJL model. The hadronic effective Lagrangian, derived by bosonization of the quark fields and renormalized using the Eguchi method, emerges in the form of an extended linear sigma model with meson and diquark-baryon fields. Chiral and diquark condensates are studied as functions of temperature and baryon density. Masses of mesons and diquark-baryons are calculated with and without the Polyakov loop effect. We investigate the equation of state of quark-hadron matter by taking into account the con…
Electromagnetic current-current correlators in pionic and nucleonic medium have been evaluated in the static limit to obtain electrical conductivities for pion and nucleon components respectively, where former decreases and latter one increases with the variation of temperature $T$ and baryon chemical potential $μ_N$. Therefore, total electrical conductivity of pion and nucleon system exhibits a valley structure in the $T$-$μ_N$ plane. To get non-divergent and finite values of correlators, finite thermal widths of medium constituents, pion and nucleon have been considered, where these thermal …
I give an estimate for the skewness and the kurtosis of the baryon number distribution in two representative models; i.e., models of a hadron resonance gas and relativistic mean-field nuclear matter. I emphasize formal similarity between these two descriptions. The hadron resonance gas leads to a deviation from the Skellam distribution if quantum statistical correlation is taken into account at high baryon density, but this effect is not strong enough to explain fluctuation data seen in the beam-energy scan at RHIC/STAR. In the calculation of mean-field nuclear matter the density correlation w…
The role of baryon-antibaryon annihilation during the hadronic stage of a relativistic heavy ion collision is explored by simulating the chemical evolution of a hadron gas. Beginning with a chemically equilibrated gas at an initial temperature of 170 MeV, the chemical composition of a representative hydrodynamic cell is followed throughout the hadronic stage. The cell's volume changes with time according to a parameterization that mimics a three-dimensional hydrodynamic expansion. The chemical evolution includes both annihilation and regeneration of baryons, consistent with detailed balance. D…
We explore the Gell-Mann--Okubo mass relation among the octet baryons using fully-dynamical, mixed-action (domain-wall on rooted-staggered) lattice QCD calculations at a lattice spacing of b ~ 0.125 fm and pion masses of m_pi ~ 290 MeV, 350 MeV, 490 MeV and 590 MeV. Deviations from the Gell-Mann--Okubo mass relation are found to be small at each quark mass.
In very high energy collisions nuclei are practically transparent to each other but produce very hot, nearly baryon-free, matter in the so-called central rapidity region. The energy in the central rapidity region comes from the kinetic energy of the colliding nuclei. We calculate the energy and rapidity loss of the nuclei using the color glass condensate model. This model also predicts the excitation energy of the nuclear fragments. Using a space-time picture of the collision we calculate the baryon and energy densities of the receding baryonic fireballs. For central collisions of gold nuclei …
Possibility of structured mixed phase at first order phase transitions is examined by taking into account of charge screening and surface effects. Hadron-quark phase transition in dense neutron star interiors is considered as a concrete example.
The hadron spectrum of SU(2) lattice gauge theory with two flavours of Wilson quark is studied on an 8^3x16 lattice using all-to-all propagators, with particular emphasis on the dependence on quark chemical potential mu. As mu is increased from zero the diquark states with non-zero baryon number B respond as expected, while states with B=0 remain unaffected until the onset of non-zero baryon density at mu=m_pi/2. Post onset the pi-meson mass increases in accordance with chiral perturbation theory while the rho becomes lighter. In the diquark sector a Goldstone state associated with a superflui…
The density dependent relativistic hadron field theory(DDRH) is extended to inclusions of pentaquark $Θ^+$. We investigate In-medium properties of $Θ^+$ and nucleons. As well as the neutron and proton,the effective $Θ^+$ mass decreases as the baryon density increases,and remains larger than nucleons'. The effective mass of $Θ^+$ is calculated,$M^*_{Θ^+}\simeq0.71M_{Θ^+}$ at normal nuclear density with the fraction of $Θ^+$ 0.2. The effective masses of all baryon increase with the increasing fraction of $Θ^+$. The binding energy is also studied. We find the binding energy is much larger than it…
