53995887
Anomalous diffusion of pions at RHIC
After pointing out the difference between normal and anomalous diffusion, we consider a hadron resonance cascade (HRC) model simulation for particle emission at RHIC and point out that rescattering in an expanding hadron resonance gas leads to a heavy tail in the source distribution. The results are compared to recent PHENIX measurements of the tail of the particle emitting source in Au+Au collisions at RHIC. In this context, we show how can one distinguish experimentally the anomalous diffusion of hadrons from a second order QCD phase transition.
14072015
Scalar Mesons and Glueballs in a Chiral U(3)xU(3) Quark Model with 't Hooft Interaction
In a U(3)x U(3) quark chiral model of the Nambu-Jona-Lasinio type with the 't Hooft interaction, the ground scalar isoscalar mesons and a scalar glueball are described. The glueball (dilaton) is introduced into the effective meson Lagrangian written in a chirally symmetric form on the base of scale invariance. The singlet-octet mixing of scalar isoscalar mesons and their mixing with the glueball are taken into account. Mass spectra of the scalar mesons and glueball and their strong decays are described.
121077448
Quark model of superconducting type and nondiagonal P-A transitions
ConclusionsWe discuss the obtained results. We note that the solution to the problem of the elimination of the unphysical interactions that arise through the P-A diagnonalization has been obtained at the prescriptional level. We have found that to eliminate the unphysical vertices due to the P-A diagnonalization, it is sufficient to replace the effective Lagrangian (22) by the Pauli-Villars regularized Lagrangian (33). The regularization is needed because of the nonuniqueness of the calculation of the individual quark diagrams that describe the new interaction vertices. The Pauli-Villars regularization corresponds to subtraction from the quark diagram of a quantity determined by the same diagram but in which all the masses of the virtual quarks are replaced by the masses of the fermions — the regularizers M. Application of the regularization for the complete effective Lagrangian has the consequence that an appropriate contribution of the regularizers is subtracted from any vertex that arises as a result of shift of the axial fields (4). This is sufficient for the correct description of the interaction vertices that arise from the P-A diagonalization.
15150236
Effective quark model with chiral U(3) x U(3) symmetry for baryon octet and decuplet
We suggest an effective quark model for low-lying baryon octet and decuplet motivated by QCD with a linearly rising confinement potential incorporating the extended Nambu--Jona-Lasinio (ENJL) model with linear realization of chiral $U(3)\ifmmode\times\else\texttimes\fi{}U(3)$ symmetry. Baryons are considered as external heavy states coupled to local three-quark currents with fixed spinorial structure and to low-lying mesons through quark-meson interactions defined in the ENJL model. In the constituent quark loop representation we have calculated the coupling constants of the $\ensuremath{\pi}NN, \ensuremath{\pi}N\ensuremath{\Delta},$ and $\ensuremath{\gamma}N\ensuremath{\Delta}$ interactions and the ${\ensuremath{\sigma}}_{\ensuremath{\pi}N}$ term. The obtained results are in reasonable agreement with experimental data and other effective field theory approaches.
122493642
On the problem of D-meson leptonic and semileptonic decays
Abstract The infinite mass effective theory, when a heavy quark mass goes to infinity, and chiral perturbation theory at the quark level, based on the extended Nambu-Jona-Lasinio model, are applied for the description of form factors of semileptonic decay D→ K e + ν e and leptonic constant FD of D-mesons. The relation is derived connecting the form factor f+(0) with the ratio F D F π , which gives the estimate F D F π =1.21±0.17 . The slope parameter of the f+ form factor is calculated in agreement with experimental data.
121038747
EFFECTIVE CHIRAL LAGRANGIANS, THE QUARK MODEL OF SUPERCONDUCTIVITY TYPE AND THE PROBLEM OF P-A DIAGONALIZATION
The vertices appearing after the inclusion of P-A transitions and a subsequent diagonalization of the chiral Lagrangian are analyzed in the quark model of superconductivity type. These vertices can conditionally be divided into physical and nonphysical ones. It is shown that if the Pauli-Villars regularization is used, the contribution of the latter can be eliminated from the description of the physical processes. This is in full agreement with the experimental data.
125071872
Exact solutions of perfect fluid hydrodynamics: Theory and applications in high-energy experiments
Some exact and explicit solutions of the relativistic hydrodynamical equations are reviewed in context of high-energy heavy ion physics. Hydrodynamics is a powerful tool to describe the experimentally observed features (e.g. scaling laws) in the final state of high-energy collisions. Hydrodynamical solutions (both exact, analytic and numerical) can then be used to draw consequences on the initial state or the equation of state of the created matter. These findings can help to reach the ultimate goal of heavy-ion physics, the mapping of the phase structure of the strong interaction. In this paper we discuss exact and phenomenologically relevant solutions of hydrodynamics, and hint at some applications of them. We detail one important application: the estimation of the initial energy density from the observed final state.
118401873
New simple explicit solutions of perfect-fluid hydrodynamics and phase-space evolution
New exact solutions of relativistic perfect-fluid hydrodynamics are presented, including the first family of exact rotating solutions. The method used to search for them is a simultaneous investigation of the relativistic hydrodynamical equations and the collisionless Boltzmann equation. Possible connections to the evolution of hot and dense partonic matter in heavy-ion collisions is discussed.
118390158
QCD EoS, initial conditions and final state from relativistic hydrodynamics in heavy-ion collisions
Some recent developments in exact results in relativistic hydrodynamics is reviewed. We discuss phenomenological applications in high-energy collisions and theoretical features of the solutions. We compare the method of numerical modelling to the strategy based on exact solutions. We argue that the efforts made and progress achieved in this seemingly purely theoretical topic is of interest for phenomenology.