Speaker
Description
The bulk viscosity of dense quark matter (QM) plays a central role in the dynamics of neutron star mergers by controlling the dissipation of density oscillations. In the neutrino-transparent regime at low temperatures, this transport coefficient is governed by the non-leptonic weak process u + d ⇆ u + s, whose microscopic rate enters directly into the QM bulk-viscosity coefficient. Despite its importance, existing perturbative calculations of this rate are only known to leading order.
In this talk, we present preliminary results for the leading O(α_s) QCD correction to the non-leptonic weak reaction rate, computed using real-time Kadanoff–Baym formalism in the low-temperature, high-density regime. The QCD correction is gauge invariant and fully ultraviolet- and infrared-finite, with all soft and collinear divergences cancelling between real and virtual contributions. Consequently, Kinoshita–Lee–Nauenberg–type infrared cancellations occur at this perturbative order for the weak flavour-changing process in dense QCD.
