相关论文: Propagation of Cool Pions
We study the neutral pion mass in the presence of an external arbitrary magnetic field in the framework of the linear sigma model coupled to quark (LSMq) at finite temperature. In doing so, we have calculated the pion self-energy,…
We present our recent results for the rho and sigma mesons considered as resonances in pion-pion scattering in a thermal bath. We use chiral perturbation theory to fourth order in p for the low energy behaviour, then extend the analysis via…
If the phase transition of $QCD$ at nonzero temperature is dominated by the (approximate) restoration of chiral symmetry, then the transition might be characterized using a gauged linear sigma model. Assuming that vector meson dominance…
The pattern of chiral symmetry breaking is exploited to compute vector and axial-vector pion matrix elements in a uniform magnetic field. Our results are model independent, and thereby constitute low-energy theorems that must be obeyed by…
Chiral symmetry of the 2-dimensional chiral Gross-Neveu model is broken explicitly by a bare mass term as well as a splitting of scalar and pseudo-scalar coupling constants. The vacuum and light hadrons - mesons and baryons which become…
We investigate non-linear extensions of the holographic soft wall model proposed by Karch, Katz, Son and Stephanov [1] including non-minimal couplings in the five-dimensional action. The non-minimal couplings bring a new parameter $a_0$…
We study the bulk viscosity of a pion gas in unitarized Chiral Perturbation Theory at low and moderate temperatures, below any phase transition to a quark-gluon plasma phase. We argue that inelastic processes are irrelevant and…
We study the chiral symmetry in two-color QCD with N massless flavors at finite temperature, using an effective theory. For the gauge group SU(2), the chiral symmetry is enlarged to SU(2N), which is then spontaneously broken to Sp(2N) at…
In the framework of the linear sigma model, we study the time evolution of a system of classical $\sigma$ and pion fields coupled to quarks. For this purpose we solve numerically the classical transport equation for relativistic quarks…
Parton distributions for the pion are studied in a chiral quark model characterized by a quark propagator for which a spectral representation is assumed. Electromagnetic and chiral symmetry constraints are imposed through the relevant…
This paper describes dynamic and thermodynamic (at $T=0$) properties of mesons in asymmetric matter in the framework of Chiral Perturbation Theory. We consider a mesonic system at vanishing temperature with nonzero isospin chemical…
It is argued that distribution over the number of charged and neutral soft chiral pions are very broad if they are emitted coherently.
We compute the charm drag and diffusion coefficients in a hot pion gas, such as is formed in a Heavy Ion Collision after the system cools sufficiently to transit into the hadron phase. We fully exploit Heavy Quark Effective Theory (with…
Within the Matsubara formalism we derive expressions for the pion self-energy and the two-pion propagator in a hot pion gas. These quantities are used to selfconsistently calculate the in-medium $\pi\pi$ amplitude beyond the quasiparticle…
We analyze chiral restoration within the $O(N+1)/O(N)$ Non-Linear Sigma Model for large $N$ as an effective theory for low-energy QCD at finite temperature $T$. The free energy is constructed diagramatically to ${\cal O}(TM^3)$ in the pion…
Two closely related topological phenomena are studied at finite density and temperature. These are chiral anomaly and Chern--Simons term. It occurs that the chiral anomaly doesn't depend on density and temperature. Chern-Simons term…
We present recent results on a systematic method to calculate transport coefficients for a meson gas (in particular, we analyze a pion gas) at low temperatures in the context of Chiral Perturbation Theory. Our method is based on the study…
We compare the behavior of overlap fermions, which are chirally invariant, and of Wilson twisted mass fermions at full twist in the approach to the chiral limit. Our quenched simulations reveal that with both formulations of lattice…
We consider the problem of soft scattering for the analogue of pion states in gauge-fermion theories which approach a conformal fixed point in the infrared limit. Introducing a fermion mass into such a theory will explicitly break both…
Skyrmions are stable and topologically non-trivial field configurations that behave like localized particles. They appear in the chiral effective theory for pions, where they correspond to the baryon states, and might also exist in the…