Non-perturbative renormalisation of four fermion operators and B-bar B mixing with Wilson fermions

TL;DR

This paper reports on non-perturbative calculations of four-fermion operators relevant to B-meson mixing, providing key renormalisation constants and a preliminary value for the B-meson mixing parameter using Wilson fermions.

Contribution

It introduces non-perturbative renormalisation results for four-fermion operators in the RI-MOM scheme with Wilson fermions, including a preliminary B-meson mixing parameter estimate.

Findings

Renormalisation constants for four-fermion operators computed non-perturbatively.

Preliminary B-meson mixing bag-parameter B_B^{RGI} = 1.46(7)(1).

Results obtained at beta=6.45 in the Landau gauge.

Abstract

We present new results for the renormalisation and subtraction constants for the four fermion Delta F=2 operators, computed non-perturbatively in the RI-MOM scheme (in the Landau gauge). From our preliminary analysis of the lattice data at beta=6.45, for the B-bar B mixing bag-parameter we obtain B_B^{RGI} = 1.46(7)(1).