Perturbative QCD correction to the nonleptonic weak rate in dense quark matter
We present the first calculation of the leading perturbative quantum chromodynamics (QCD) correction to the nonleptonic weak flavor-equilibration rate in dense quark matter. The computation is based on the Kadanoff-Baym kinetic equation and performed using real-time thermal field theory. The resulting QCD correction is both gauge invariant and fully finite. In particular, all soft and collinear divergences cancel after combining real and virtual corrections, in accordance with the Kinoshita-Lee-Nauenberg theorem. In the low-temperature regime relevant to compact-star dynamics, the correction enhances the tree-level rate by $30 - 40\%$ over the high-density range where perturbative QCD is applicable. The corrected rate improves on the tree-level result used in phenomenological calculations for more than three decades, providing a more accurate microscopic input for bulk-viscosity calculations in dense quark matter.