  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.
