Quark and gluon condensates in the Nambu–Jona–Lasinio model at finite temperature

The temperature dependence of the amplitude for decay of a scalar meson into two photons is investigated. This result is used to describe the behavior of the masses of constituent quarks, and also the behavior of the quark and gluon condensates at finite temperatures in the Nambu–Jona–Lasinio model. It is shown that the temperature dependence of all the physical quantities is determined solely by thermal variations of the divergent quark loops.