The propagation of the scalar (σand δ) and vector (ωand ρ) mesons in an iso-asymmetric nuclear matter is studied in detail, using the Walecka model. We calculate the invariant masses and spectral functions of the mesons, including the effect of meson mixing. At finite density, the mixing effect is quite important in the propagation of the scalar and (longitudinal) vector mesons. In the σchannel, we find a three-peak structure in the spectral function, caused by the mixing effect.
It is argued that the experimentally observed phenomenon of asymmetric vector mesons produced in nuclear media during high energy nucleus-nucleus collisions can be explained as Cherenkov and Fano effects. The mass distributions of lepton pairs created at meson decays decline from the traditional Breit-Wigner shape in the low-mass wing of the resonance. That is explained by the positive real part of the amplitude in this wing for classic Cherenkov treatment and further detalized in quantum mechanics as the interference of direct and continuum states in Fano effect. The corresponding parameters …
The rho meson spectral function in hot and dense asymmetric nuclear matter (number densities of proton and neutron different) is evaluated in an effective chiral SU(3) model within the mean field approximation (MFA). The dependence of the vector meson masses on density and temperature, their variation with the asymmetry parameter, the form of the spectral function when the p <-> n symmetry is broken are studied. One can observe clear splitting of the longitudinal and the transverse modes among the rho isospin multiplets. The role of a running tensor coupling on the spectral function is also st…
We study the in-medium properties of $D$ and $\bar{D}$ mesons in isospin-asymmetric nuclear matter at finite temperatures using an effective chiral SU(4) model. The interactions of $D$ and $\bar{D}$ mesons with nucleons, scalar isoscalar meson $σ$, and scalar iso-vector meson $δ$ are taken into consideration. It is found that as compared to the $\bar{D}$ mesons, the properties of the $D$ mesons are observed to be quite sensitive to the isospin-asymmetry at high densities. At finite densities, the masses of $D$ and $\bar{D}$ mesons observed at finite temperatures are seen to be higher in compar…
The quark-meson-coupling model is used to study droplet formation from the liquid-gas phase transition in cold asymmetric nuclear matter. The critical density and proton fraction for the phase transition are determined in the mean field approximation. Droplet properties are calculated in the Thomas-Fermi approximation. The electromagnetic field is explicitly included and its effects on droplet properties are studied. The results are compared with the ones obtained with the NL1 parametrization of the non-linear Walecka model.
The running of the $ρ\bar N N$ couplings in presence of nuclear matter is studied, and the relevant $β$-functions are shown to be different for $ρ^0$ and $ρ^+$, when the nuclear medium is asymmetric.
We calculate dispersion relations and propagators for the $σ$, $ω$, $ρ$ and $δ$ mesons in relativistic nuclear matter with a proton-neutron asymmetry. In addition to the $σ$-$ω$ and $δ$-$ρ$ mixings already present in symmetric matter, mixing occur between all components of the $σ$-$ω$-$δ$-$ρ$ system when the proton fraction differs from 1/2.
In the present work we include the isovector-scalar $δ$-meson in the quark-meson coupling model (QMC) and study the properties of asymmetric nuclear within QMC without and with the $δ$-meson. Recent constraints set by isospin diffusion on the slope parameter of the nuclear symmetry energy at saturation density are used to adjust the model parameters. The thermodynamical spinodal surfaces are obtained and the instability region at subsaturation densities within QMC and QMC$δ$ models are compared with mean-field relativistic models. The distillation effect in the QMC model is discussed.
The Hidden Local Symmetry Lagrangian is used to study the interactions of phi mesons with other pseudoscalar and vector mesons in a hadronic gas at finite temperature. We have found a significantly small phi mean free path (less than 2.4 fm at T > 170 MeV) due to large collision rates with rho mesons, kaons and predominantly K* in spite of their heavy mass. This implies that phi mesons produced after hadronization in relativistic heavy ion collisions will not leave the hadronic system without scattering. The effect of these interactions on the time evolution of the phi density in the expanding…
It is argued that the experimentally observed phenomenon of asymmetric shapes of vector mesons produced in nuclear media during high energy nucleus-nucleus collisions can be explained as Fano-Feshbach resonances. It has been observed that the mass distributions of lepton pairs created at meson decays decline from the traditional Breit-Wigner shape with some excess in the low-mass wing of the resonance. It is clear that the whole phenomenon is related to some interaction with the nuclear medium. Moreover, it can be further detalized in quantum mechanics as the interference of direct and continu…
We study the in-medium properties of $D$ and $\bar{D}$ mesons in isospin asymmetric hyperonic matter arising due to their interactions with the light hadrons. The interactions of $D$ and $\bar{D}$ mesons with these light hadrons are derived by generalizing the chiral SU(3) model used for the study of hyperonic matter to SU(4). The nucleons, the scalar isoscalar meson, $σ$ and the scalar-isovector meson, $δ$ as modified in the strange hadronic matter, modify the masses of $D$ and $\bar{D}$ mesons. It is found that as compared to the $\bar{D}$ mesons, the $D$ meson properties are more sensitive …
We study the medium modifications of the spectral functions as well as production cross-sections of the strange vector mesons ($ϕ$, $K^*$ and $\bar {K^*}$) in isospin asymmetric strange hadronic matter. These are obtained from the in-medium masses of the open strange mesons and the decay widths $ϕ\rightarrow K\bar K$, $K^* \rightarrow Kπ$ and $\bar {K^*} \rightarrow {\bar K}π$ in the hadronic medium. The decay widths are computed using a field theoretic model of composite hadrons with quark/antiquark constituents, from the matrix element of the light quark-antiquark pair creation term of the f…
In this work we study the warm equation of state of asymmetric nuclear matter in the quark meson coupling model which incorporates explicitly quark degrees of freedom, with quarks coupled to scalar, vector and isovector mesons. Mechanical and chemical instabilities are discussed as a function of density and isospin asymmetry. The binodal section, essential in the study of the liquid-gas phase transition is also constructed and discussed. The main results for the equation of state are compared with two common parametrizations used in the non-linear Walecka model and the differences are outlined…
We investigate the in-medium masses of $D$ and $\bar{D}$ mesons in the isospin-asymmetric nuclear matter at finite temperatures arising due to the interactions with the nucleons, the scalar isoscalar meson $σ$, and the scalar iso-vector meson $δ$ within a SU(4) model. The in-medium masses of $J/ψ$ and the excited charmonium states ($ψ(3686)$ and $ψ(3770)$) are also calculated in the hot isospin asymmetric nuclear matter in the present investigation. These mass modifications arise due to the interaction of the charmonium states with the gluon condensates of QCD, simulated by a scalar dilaton fi…
Using the relativistic mean-field model with nonlinear couplings between the isoscalar and isovector mesons, we study the properties of isospin-asymmetric nuclear matter. Not only the vector mixing, $ω_μω^μ\mathbfρ_ν\mathbfρ^ν$, but also the quartic interaction due to the scalar mesons, $σ^{2}\mathbfδ^{2}$, is taken into account to investigate the density dependence of nuclear symmetry energy, $E_{\rm sym}$, and the neutron-star properties. It is found that the $δ$ meson increases $E_{\rm sym}$ at high densities, whereas the $σ$-$δ$ mixing makes $E_{\rm sym}$ soft above the saturation density.…
We study the propagation of the light mesons sigma, omega, rho, and a0(980) in dense hadronic matter in an extended derivative scalar coupling model. Within the scheme proposed it is possible to unambiguously define effective density-dependent couplings at the Lagrangian level. We first apply the model to study asymmetric nuclear matter with fixed isospin asymmetry, and then we pay particular attention to hypermatter in beta-equilibrium. The equation of state and the potential contribution to the symmetry coefficient arising from the mean field approximation are investigated.
Using a purely hadronic model, we study the charge-symmetry-breaking $ρ$-$ω$, $σ$-$δ$, $σ$-$ρ$ and $δ$-$ω$ mixing amplitudes in isospin asymmetric nuclear matter. The basic assumption of the model is that the mixing amplitude is generated by nucleon and anti-nucleon loops and hence driven entirely by the difference between proton and neutron Fermi momenta and the proton-neutron mass difference. We find that the behavior of the mixing amplitude is very complicated in the spacelike region and quite sensitive to the proton fraction of nuclear medium and nuclear density. In particular, in neutron …
We reexamine effects of the $ρ-ω$ meson mixing mediated by nucleon polarizations on the symmetry energy in isospin-asymmetric nuclear matter. Taking into account the rearrangement term neglected in previous studies by others, we evaluate the $ρ-ω$ mixing angle in a novel way within the Relativistic Mean-Field Models with and without chiral limits. It is found that the symmetry energy is significantly softened at high densities contrary to the finding in earlier studies. As the first step of going beyond the lowest-order calculations, we also solve the RPA equation for the $ρ-ω$ mixing. In this…
The modifications of the masses of the $B$ and $\bar B$ mesons in asymmetric nuclear matter in the presence of strong magnetic fields, are investigated using a chiral effective model. The medium modifications of these open bottom mesons arise due to their interactions with the scalar mesons and the nucleons. In the magnetized nuclear matter, the proton has contributions from the Landau levels. In the chiral effective model, the masses of the $B$ and $\bar B$ are calculated from the leading term, namely the vectorial Weinberg Tomozawa term as well as from the next to leading order contributions…
The medium modifications of the open charm mesons ($D$ and $\bar D$) are studied in isospin asymmetric nuclear matter in the presence of strong magnetic fields, using a chiral effective model. The mass modifications of these mesons in the effective hadronic model, arise due to their interactions with the protons, neutrons and the scalar mesons (non-strange isoscalar $σ$, strange isoscalar, $ζ$ and non-strange isovector, $δ$), in the magnetized nuclear matter. In the presence of magnetic field, for the charged baryon, i.e., the proton, the number density as well as the scalar density have contr…
We study a spectral function for $\bar{D}_0^*$ $(0^+)$ meson in symmetric and neutron-rich asymmetric nuclear matter from the viewpoint of the partial restoration of chiral symmetry. Nuclear matter is constructed by a parity doublet model with hidden local symmetry which can reproduce properties at normal nuclear matter density as well as those in the vacuum. $\bar{D}$ mesons are introduced by the chiral partner structure. Our results show that a mass of $\bar{D}$ ($0^-$) meson increases while a mass of $\bar{D}_0^*$ meson decreases at mean field level as we increase the baryon density, reflec…
We observed the impact of finite magnetic field on the in-medium mass and decay constant of isospin averaged vector $D^*(D^{*^+},D^{*^0})$ and axial-vector $D_1(D^+_1, D^0_1)$ mesons. The quark and gluon condensates of the nuclear medium at finite magnetic field, temperature, isospin asymmetry, and density have been obtained by the meson exchange scalar fields within the chiral SU(3) model. The medium attributes modify the scalar and vector density of nuclear medium and this variation reflects in the in-medium mass and decay constant of spin 1 $D$ mesons. We calculate these observables by comp…
Microscopic calculation of two-particle-two-hole meson-exchange currents in $^{40}$Ar and asymmetric scaling properties for neutrino and electron scattering
The in-medium masses and optical potentials of $B$ and ${\bar B}$ mesons are studied in an isospin asymmetric, strange, hot and dense hadronic environment using a chiral effective model. The chiral $SU(3)$ model originally designed for the light quark sector, is generalized to include the heavy quark sector ($c$ and $b$) to derive the interactions of the $B$ and ${\bar B}$ mesons with the light hadrons. Due to large mass of bottom quark, we use only the empirical form of these interactions for the desired purpose, while treating the bottom degrees of freedom to be frozen in the medium. Hence, …
We study the $ηN$ interactions in the hot and dense isospin asymmetric nuclear matter using two different approaches. In the first approach, the in-medium mass and optical potential of $η$-meson have been calculated in the chiral SU(3) model, considering the effect of explicit symmetry breaking term and range terms in the $ηN$ interaction Lagrangian density. In the second scenario, the conjunction of chiral perturbation theory and chiral SU(3) model is employed. In this case, the next-to-leading order $ηN$ interactions are evaluated from the chiral perturbation theory (ChPT), and the in-medium…
We calculate the effects of finite density of isospin asymmetric strange hadronic matter, for different strangeness fractions, on the in-medium properties of vector $\left( D^{\ast}, D_{s}^{\ast}, B^{\ast}, B_{s}^{\ast}\right)$ and axial-vector $\left( D_{1}, D_{1s}, B_{1}, B_{1s}\right)$ mesons using chiral hadronic SU(3) model and QCD sum rules. We focus on the evaluation of in-medium mass-shift and shift of decay constant of above vector and axial vector mesons. In QCD sum rule approach the properties e.g. masses and decay constants of vector and axial vector mesons are written in terms of …
The propagation of the scalar ($σ$) and vector ($ω$) mesons in nuclear matter is studied in detail using the Walecka model over a wide range of densities and including the effects of a finite $σ$ width through the inclusion of a two-pion loop. We calculate the dispersion relation and spectral functions of the $σ$ and (transverse and longitudinal) $ω$ mesons, including the effect of $σ$-$ω$ mixing in matter. It is shown that the mixing effect is quite important in the propagation of the (longitudinal) $ω$ and $σ$ mesons above normal nuclear matter density. We find that there is a two-peak struc…
The properties of vector mesons in nuclear matter are discussed. Results for the momentum dependence of the $ρ$-meson self energy in matter due to $ρN$ interactions are presented, and consequences for the production rate of $e^+e^-$ pairs in hot and dense matter are discussed. I also examine the constraints imposed by elementary processes on the widths of $ρ$ and $ω$ mesons in nuclear matter, and conclude that in recent models the in-medium widths of these mesons are overestimated.
We calculate the in-medium $D$ and $\bar D$-meson masses in isospin asymmetric nuclear matter in an effective chiral model. The $D$ and $\bar D$ - mass modifications arising from their interactions with the nucleons and the scalar mesons in the effective hadronic model are seen to be appreciable at high densities and have a strong isospin dependence. These mass modifications can open the channels of the decay of the charmonium states ($Ψ^\prime$, $χ_c$, $J/Ψ$) to $D \bar D$ pairs in the dense hadronic matter. The isospin asymmetry in the doublet $D=(D^0,D^+)$ is seen to be particularly appreci…
Asymmetric nuclear matter is studied in the frame of relativistic mean-field theory, using scalar-isoscalar sigma, vector-isoscalar omega meson together with their selfinteractions, vector-isovector rho meson with its cross-interaction with omega meson too, and scalar-isovector delta meson as degrees of freedom. The model is used to parameterize the nuclear matter properties results calculated by more fundamental Dirac-Brueckner-Hartree-Fock theory and thus to provide an effective DBHF model applicable also to finite nuclei. Vector omega-rho cross-interaction seems to be an useful degree of fr…
We calculate the effects of finite density and temperature of isospin asymmetric strange hadronic matter, for different strangeness fractions, on the in-medium properties of vector $\left( D^{\ast}, D_{s}^{\ast}, B^{\ast}, B_{s}^{\ast}\right)$ and axial-vector $\left( D_{1}, D_{1s}, B_{1}, B_{1s}\right)$ mesons, using chiral hadronic SU(3) model and QCD sum rules. We focus on the evaluation of in-medium mass-shift and shift in decay constant of above vector and axial-vector mesons. In QCD sum rule approach, the properties, e.g., the masses and decay constants of vector and axial-vector mesons …
The drag force and diffusion coefficients for a D meson are calculated in hot dense matter composed of light mesons and baryons, such as it is formed in heavy-ion collisions. We use a unitarized approach based on effective models for the interaction of a D meson with hadrons, which are compatible with chiral and heavy quark symmetries. We study the propagation of the D meson in the hadron matter in two distinct cases. On the one hand, we analyze the propagation of D mesons in matter at vanishing baryochemical potential, which is relevant for high-energetic collisions at LHC or RHIC. On the oth…
We apply a BUU type transport model for the interpretation of the di-electron invariant mass spectrum measured by the HADES collaboration for the reaction C(2 AGeV) + C. Our model incorporates the propagation of broad meson resonances emerging from the decay of baryon resonances.
The in-medium properties of $D_S$ mesons are investigated within the framework of an effective hadronic model, which is a generalization of a chiral SU(3) model, to SU(4), in order to study the interactions of the charmed hadrons. In the present work, the $D_s$ mesons are observed to experience net attractive interactions in a dense hadronic medium, hence reducing the masses of the $D_S^+$ and $D_S^-$ mesons from the vacuum values. While this conclusion holds in both nuclear and hyperonic media, the magnitude of the mass drop is observed to intensify with the inclusion of strangeness in the me…
The in-medium partial decay widths of $Υ(4S) \rightarrow B\bar B$ in magnetized asymmetric nuclear matter are studied using a field theoretic model for composite hadrons with quark (and antiquark) constituents. The medium modifications of the decay widths of $Υ(4S)$ to $B\bar B$ pair in magnetized matter arise due to the mass modifications of the decaying $Υ(4S)$ as well as of the produced $B$ and $\bar B$ mesons. The in-medium masses of the open bottom meson in magnetized nuclear matter are computed from their interactions with the nucleons and the scalar mesons within a chiral effective mode…
We study the properties of $D$ and $\bar{D}$ mesons in hot isospin asymmetric strange hadronic matter, arising due to their interactions with the hadrons in the hyperonic medium. The interactions of $D$ and $\bar{D}$ mesons with these light hadrons are derived by generalizing the chiral SU(3) model used for the study of hyperonic matter to SU(4). We also study the mass modifications of the charmonium states $J/ψ$, $ψ(3686)$ and $ψ(3770)$ in the isospin asymmetric strange hadronic matter at finite temperatures and investigate the possibility of the decay of the charmonium states into $D\bar D$ …
We construct a model to describe dense hadronic matter at zero and finite temperature, based on the parity doublet model of DeTar and Kunihiro, with including the iso-singlet scalar meson $σ$ as well as $ρ$ and $ω$ mesons. We show that, by including a six-point interaction of $σ$ meson, the model reasonably reproduces the properties of the normal nuclear matter with the chiral invariant nucleon mass $m_0$ in the range from $500~{\rm MeV}$ to $900~{\rm MeV}$. Furthermore, we study the phase diagram based on the model, which shows that the value of the chiral condensate drops at the liquid-gas p…
The bosonic excitations induced by the omega meson propagation in dense nuclear matter is studied within the framework of random phase approximation. The collective modes are then analyzed by finding the zeros of the relevant dielectric functions. Subsequently we present closed form analytical expressions for the dispersion relations in different kinematical regime. Next, the analytical behaviour of the in-medium effective propagator for the omega meson is examined. This is exploited to calculate the full spectral function for the transverse (T) and longitudinal (L) mode of the omega meson. In…
We study pion propagation in asymmetric nuclear matter (ANM). One of the interesting consequences of pion propagation in ANM is the mode splitting for the different charged states of pions. First we describe the pion-nucleon dynamics using the non-chiral model where one starts with pseudoscalar (PS) $π$N coupling and the pseudovector (PV) representation is obtained via suitable non-linear field transformations. For both of these cases the effect of the Dirac sea is estimated. Subsequently, we present results using the chiral effective Lagrangian where the short-distance behavior (Dirac vacuum)…
We study the propagation of non-strange and strange meson modes in hadronic matter considering both isospin and strangeness mixings induced by quantum fluctuations in the medium. Baryons are described using the Quark Meson Coupling model extended to include interactions of strange quarks. In particular we evaluate the dependence of the meson masses on the baryonic density, the strangeness fraction and the isospin asymmetry of the medium. We have found a considerable admixture of strangeness and isospin in the sigma-mode in the high density regime.
The vacuum fluctuation (VF) effects on asymmetric nuclear matter are investigated. Masses of nucleons and mesons are modified in the nuclear medium by calculating the loop-diagram corrections and the density dependence of hadron masses is obtained. The relativistic Lagrangian density with the isovector scalar $δ$ meson is used to calculate the nuclear equation of state (EOS) in the framework of the relativistic mean-field (RMF) approach, the effects of the in-medium hadron masses on the properties of neutron stars are finally studied. With the inclusion of the VF corrections, the nuclear EOS b…
Using various relativistic mean-field models, including the nonlinear ones with meson field self-interactions, those with density-dependent meson-nucleon couplings, and the point-coupling models without meson fields, we have studied the isospin-dependent bulk and single-particle properties of asymmetric nuclear matter. In particular, we have determined the density dependence of nuclear symmetry energy from these different relativistic mean-field models and compare the results with the constraints recently extracted from analyses of experimental data on isospin diffusion and isotopic scaling in…
The time evolution of vector-meson spectral-functions is studied within a kinetic theory approach. We implement this formalism in a BUU type transport model. Applications focus on rho and omega mesons being important pieces for the interpretation of the di-electron invariant mass spectrum measured by the HADES collaboration for the reaction C + C at 2 AGeV bombarding energy. Since the evolution of the spectral functions is driven by the local density, the in-medium modifications are tiny for small collision systems within this approach.
We employ recently published cross sections for $D$-mesons with hadrons and calculate the drag and diffusion coefficients of $D$-mesons in hadronic matter as a function of the momentum of $D$-mesons as well as of the temperature of the medium. Calculating in our approach the spatial diffusion coefficient, $D_x$, at zero chemical potential we see a very smooth transition between our calculations for the hadron gas and the lattice QCD calculations. Applying the results for the transport coefficients of $D$-mesons in a Fokker-Planck equation, which describes the evolution of $D$-mesons during the…
Based on a realistic model for the rho meson in free space we investigate it's medium modifications in a hot hadron gas generated by hadronic rescattering processes, i.e. renormalization of intermediate two-pion states as well as direct rho meson scattering off hadrons. Within the vector dominance model the resulting in-medium rho spectral function is applied to calculate $e^+e^-$ spectra as recently measured in heavy-ion collisions at CERN-SpS energies in the CERES experiment.
We investigate the QCD phase diagram of isospin asymmetric matter using the Polyakov loop extended quark meson (PQM) model with vector interaction. The critical point temperature is found to decrease in isospin asymmetric matter and disappear at large isospin chemical potential. We also discuss the QCD phase transition in the neutron star core. From comparison of the QCD phase diagram in PQM and corresponding baryon and isospin chemical potentials of neutron star matter in relativistic mean field models, we show that the order of the chiral phase transition in the neutron star core could be cr…
We consider the early cooling evolution of strongly magnetized strange stars in a CFL phase with high gap Delta > 100 MeV. We demonstrate how this model may explain main features of the gamma-ray burst phenomena and also yield a strong star kick. The mechanism is based on beaming of neutrino emission along the magnetic vortex lines. We show that for sufficiently high initial temperatures T_0 ~ 30 - 60 MeV and surface magnetic fields B_s ~ 10^{15} - 10^{17} G, the energy release within the narrow beam is up to 10^{52} erg with a magnetic field dependent time scale between 10^{-2} s (for a small…
Density dependent parametrization models of the nucleon-meson effective couplings, including the isovector scalar δ-field, are applied to asymmetric nuclear matter. The nuclear equation of state and the neutron star properties are studied in an effective Lagrangian density approach, using the relativistic mean field hadron theory. It is known that the introduction of a δ-meson in the constant coupling scheme leads to an increase of the symmetry energy at high density and so to larger neutron star masses, in a pure nucleon-lepton scheme. We use here a more microscopic density dependent model of…
The interaction and propagation of anti-B mesons with light mesons, N and Delta baryons is studied within a unitarized approach based on effective models that are compatible with chiral and heavy-quark symmetries. We find several heavy-quark spin doublets in the open-bottom sectors, where anti-B and anti-B* mesons are present. In the meson sector we find several resonant states, among them, a B0 and a B1 with masses 5530 MeV and 5579 MeV as well as Bs0* and Bs1* narrow states at 5748 MeV and 5799 MeV, respectively. They form two doublets with no experimental identification yet, the first one b…
The Equation of State (EOS) for asymmetric nuclear matter is discussed starting from a phenomenological hadronic field theory of Serot-Walecka type including exchange terms. In a model with self interactions of the scalar sigma-meson we show that the Fock terms naturally lead to isospin effects in the nuclear EOS. These effects are quite large and dominate over the contribution due to isovector mesons. We obtain a potential symmetry term of "stiff" type, i.e. increasing with baryon density and an interesting behaviour of neutron/proton effective masses of relevance for transport properties of …
We study spectral properties of the phi meson at finite temperature using an effective Lagrangian together with finite-temperature field theory as a basis for modeling. General field-theoretic arguments are then used to establish the lifetime of the phi in hot hadronic matter. We find from the model, and we therefore propose a scenario in which, the phi decays inside the fireball. Early decays into $μ^{+}μ^{-}$ occur at high temperature while measurable hadronic decays into $K^{+}K^{-}$ (not suffering rescattering) occur at freezeout, where flow could be substantial. These results provide a co…
Relativistic mean-field theory with $δ$ meson, nonlinear isoscalar self-interactions and isoscalar-isovector cross interaction terms with parametrizations obtained to reproduce Dirac-Brueckner-Hartree-Fock calculations for nuclear matter is used to study asymmetric nuclear matter properties in $β$-equilibrium, including hyperon degrees of freedom and (hidden) strange mesons. Influence of cross interaction on composition of hyperon matter and electron chemical potential is examined. Softening of nuclear equation of state by the cross interactions results in lowering of hyperonization, although …
The density dependent relativistic hadron field (DDRH) theory is applied to strongly asymmetric nuclear matter and finite nuclei far off stability. A new set of in-medium meson-nucleon vertices is derived from Dirac-Brueckner Hartree-Fock (DBHF) calculations in asymmetric matter, now accounting also for the density dependence of isovector coupling constants. The scalar-isovector $δ$ meson is included. Nuclear matter calculations show that it is necessary to introduce a momentum correction in the extraction of coupling constants from the DBHF self-energies in order to reproduce the DBHF equatio…
The problem of propagation of photons and massive vector mesons in the presence of Lorenz and CPT invariance violating medium is studied when the parity-odd medium is bounded by a hyperplane separating it from the vacuum. The solutions in both half-spaces are carefully discussed and in the case of space-like boundary stitched on the boundary with help of the Bogolubov transformations provided by the space-like Chern-Simons vector. The presence of two different Fock vacua is shown and the probability amplitude for transmission of particles from vacuum to parity breaking medium is calculated. We…
We study the dispersion relations of mesons in a particular hot strongly coupled supersymmetric gauge theory plasma. We find that at large momentum k the dispersion relations become omega = v_0 k + a + b/k + ..., where the limiting velocity v_0 is the same for mesons with any quantum numbers and depends only on the ratio of the temperature to the quark mass T/m_q. We compute a and b in terms of the meson quantum numbers and T/m_q. The limiting meson velocity v_0 becomes much smaller than the speed of light at temperatures below but close to T_diss, the temperature above which no meson bound st…
