Neutral B-meson mixing from dynamical lattice QCD with chiral light quarks and static b-quarks

TL;DR

This paper calculates B-meson mixing parameters using lattice QCD with chiral light quarks and static b-quarks, providing improved results for SU(3)-breaking ratios and decay constants relevant for flavor physics.

Contribution

It introduces a lattice QCD calculation of B-meson mixing ratios employing chiral fermions and static b-quarks, with enhanced matching and chiral extrapolation techniques.

Findings

Computed SU(3)-breaking ratio xi for B-meson mixing.

Determined ratio of decay constants f_{B_s}/f_{B_d}.

Validated method on a specific lattice ensemble.

Abstract

In the limit of infinitely heavy b-quarks we compute the SU(3)-breaking ratio xi of neutral B-meson mixing matrix elements. We also present results for the ratio of decay constants f_{B_s}/f_{B_d}. Our calculation employs chirality-preserving domain-wall fermions for the light quarks, a static action with link-smearing for the b-quarks, and the Iwasaki gauge action. Here we report on our results from the 16^3 x 32 x 16 ensemble (a^-1 = 1.729(28) GeV) which we use to verify our method. We improve upon our earlier work by including O(alpha_s pa) matching for the computation of the decay constants and extrapolating to the physical point using chiral perturbation theory.