Neutron-Antineutron Operator Renormalization

TL;DR

This paper discusses the calculation of operator renormalization effects for neutron-antineutron transition operators using perturbative QCD, crucial for connecting lattice results with beyond Standard Model theories.

Contribution

It presents the ongoing computation of two-loop anomalous dimensions and one-loop matching coefficients for six-quark operators relevant to neutron-antineutron oscillations.

Findings

Preliminary lattice calculations performed.

Perturbative renormalization effects are being computed.

Results will improve the accuracy of transition rate predictions.

Abstract

Baryon number symmetry violating theories beyond the standard model with suppressed proton decay rates can be experimentally constrained by data on neutron-antineutron transition rates. In order to apply this constraints, theoretical predictions for the neutron-antineutron transition rates in various models must be available for comparison. Reliable predictions of transition rates between hadronic states must include non-perturbative quantum chromodynamic effects. These can be calculated in a model independent way by calculating six-quark operator matrix elements with lattice quantum chromodynamics. Preliminary lattice calculations have been performed, but operator renormalization effects must be included in order to match beyond the standard model calculations performed in $\overline{MS}$ renormalized perturbation theory with lattice regularized matrix element results. In particular, a perturbative calculation of the two-loop anomalous dimensions and one-loop renormalization scheme matching coefficients of these six-quark operators is necessary in order to determine leading order corrections at lattice matching scales. This describes our ongoing calculation of these perturbative operator renormalization effects.