Thermal properties of heavy-light quark pseudoscalar and vector mesons

Abstract

The thermal behaviour of the mass, leptonic decay constant, and width of heavy-light quark peseudoscalar and vector mesons is analized in the framework of thermal Hilbert moment QCD sum rules. In all the cases, the meson leptonic decay constants decrease with increasing T , and vanish at a critical temperature Tc, while the mesons develop a width which increases dramatically, diverging when T ! Tc, where Tc is the temperature for chiral-symmetry restoration. The spectral function becomes a smooth function of the energy. This is interpreted as a signal for deconfinement at T = Tc. In contrast, the thermal masses are stable, except when T ! Tc, where the pseudoscalar meson mass increases slightly by 10-20 %, and the vector meson mass decreases by some 20-30 %.