Related papers: The pion at finite temperature
The equation of state of pure QCD, obtained from lattice QCD, is discussed for temperatures ranging from $0.9\tc$ to $4\tc$, as well as results on screening masses, the chiral condensate, and the pion decay constant close to the…
We present results on the equation of state in QCD with two light quark flavors and a heavier strange quark. Calculations with improved staggered fermions have been performed on lattices with temporal extent Nt =4 and 6 on a line of…
The grand canonical ensemble formulation of the van der Waals equation of state that includes the effects of Bose statistics is applied to an equilibrium system of interacting pions. If the attractive interaction between pions is large…
In this talk, we report our recent work on the pion weak decay constant (F_pi) and pion mass (m_pi) using the nonlocal chiral quark model with the finite quark-number chemical potential (mu) taken into account. Considering the breakdown of…
We investigate the low-temperature phase of QCD and the crossover region with two light flavors of quarks. The chiral expansion around the point $(T, m_q = 0)$ in the temperature vs. quark-mass plane indicates that a sharp real-time…
We present a lattice QCD based determination of the chiral phase transition temperature in QCD with two degenerate, massless quarks and a physical strange quark mass. We propose and calculate two novel estimators for the chiral transition…
We consider chiral perturbation theory for SU(2) at finite temperature $T$ in a constant magnetic background $B$. We compute the thermal mass of the pions and the pion decay constant to leading order in chiral perturbation theory in the…
We study the behavior of the pion dispersion relation in a pion medium at finite density and temperature. We introduce a pion chemical potential to describe the finite pion number density and argue that such description is valid during the…
A simple matching procedure is proposed to extract constraints on effective meson theories. In this way, a QCD prediction for the pion decay constant is found, F(pi)=2 m(pi)/pi, i.e. approximately 90MeV. The same procedure also determines…
The chiral phase transition temperature $T_{c}^{0}$ is a fundamental quantity of QCD. To determine this quantity we have performed simulations of (2 + 1)-flavor QCD using the Highly Improved Staggered Quarks (HISQ/tree) action on…
We study the behavior of the pion dispersion relation in a pion medium at finite density and temperature, introducing a chemical potential to describe the finite pion number density. Such description is particularly important during the…
We review the relationship between the pion decay constant $f_\pi$, the chiral symmetry restoration temperature $T_c$ and the phenomenology of low energy chiral symmetry breaking in view of the recent confirmation of the existence of a…
Using only global symmetries of QCD, we set up an effective model of quarks at finite temperature near the cross over, including all possible terms up to dimension 6. We first treat this in mean field theory. Then we investigate low-energy…
The pion-nucleon coupling constant $g_{\pi N}$ is studied on the basis of the QCD sum rules. Both the Borel sum rules and the finite energy sum rules for $g_{\pi N}$ are used to examine the effects of higher dimensional operators (up to…
We continue our investigation of the QCD dynamics in terms of the Curci-Ferrari effective Lagrangian, a deformation of the Faddeev-Popov one in the Landau gauge with a tree-level gluon mass term. In a previous work we have studied the…
A thermal Finite Energy QCD Sum Rule is used to determine the temperature behaviour of the $\omega \rho \pi$ strong coupling. This coupling decreases with increasing $T$ and vanishes at the critical temperature, a likely signal for quark…
We review the theory that predicts that the decay constant of the excited light pseudo-scalar mesons are suppressed in the chiral limit relative to the pion decay constant. We compute the decay constant of the first excited pion…
We study the topological susceptibility, chi, in QCD with two quark flavours using lattice field configurations that have been produced with an O(a) improved quark action. We find clear evidence for the expected suppression at small quark…
Vector ($\Upsilon$) and pseudoscalar ($\eta_b$) bottonium ground states are studied at finite temperature in the framework of thermal Hilbert moment QCD sum rules. The mass, the onset of perturbative QCD in the complex squared energy plane,…
Using the ideas of effective field theory and dimensional reduction, we relate the parameters of two low energy models of QCD: the O(N) nonlinear sigma model in D=3+1, which describes the dynamics of cool pions, and the O(N) Heisenberg…