2025/09/28 by Comitini, Giorgio
#FOS: Physical sciences #High Energy Physics - Theory (hep-th)
paper · doi:10.48550/arxiv.2509.23889
With the aim of looking for signatures of deconfinement, the poles and the spectral function of the Landau-gauge gluon propagator are investigated at one loop, vanishing spatial momentum and finite temperature within the framework of the screened massive expansion of pure Yang-Mills theory and of full QCD. When computed using both temperature-independent parameters optimized by principles of gauge invariance and temperature-dependent parameters obtained by fitting lattice data at zero Matsubara frequency, the propagator is found to have a pair of complex-conjugate poles in its squared complexified frequency variable throughout the considered temperature interval, ranging from T=0 to temperatures T>Tc of interest to quark-gluon plasma phenomenology. The spectral function is found to violate positivity and not to develop sharp peaks over said temperature interval. In full QCD, a simple model is used for mass generation in the infrared quark sector; the dependence of our results on the quark masses is discussed.