Lattice calculation of gluon screening masses

We study SU(3) gluon electric and magnetic masses at finite temperatures using quenched lattice QCD on a $20^2 \times 32 \times 6$ lattice. We focus on temperature regions between $T=T_c$ and $6T_c$, which are realized in BNL Relativistic Heavy Ion Collider and CERN Large Hadron Collider experiments. Stochastic quantization with a gauge-fixing term is employed to calculate gluon propagators. The temperature dependence of the electric mass is found to be consistent with the hard-thermal-loop perturbation, and the magnetic mass has finite values in the temperature region of interest. Both screening masses have little gauge parameter dependence. The behavior of the gluon propagators is very different in confinement/deconfinement physics. The short distance magnetic part behaves like a confined propagator even in the deconfinement phase. A simulation with a larger lattice, $32^2 \times 48 \times 6$, shows that the magnetic mass has a stronger finite size effect than the electric mass.