B Meson Decay Constants Using Relativistic Heavy Quarks

TL;DR

This paper updates calculations of B meson decay constants using relativistic heavy quarks on lattice QCD, providing precise ratios relevant for phenomenology.

Contribution

It introduces an improved lattice QCD calculation of B meson decay constants with relativistic heavy quarks and multiple lattice spacings.

Findings

Calculated decay constants for B, Bs, and Bc mesons.

Determined ratios like f_{Bs}/f_B and f_{B*}/f_B.

Results are consistent across different lattice spacings.

Abstract

We present an update on ongoing work to extract pseudoscalar and vector decay constants for $B^{(*)}$, $B^{(*)}_s$ and $B^{(*)}_c$ mesons and determine phenomenologically-interesting ratios such as $f_{B_s}/f_B$ or $f_{B^*}/f_B$. Our calculation is based on ${\rm N_f}=2+1$ dynamical flavour gauge field ensembles generated by the RBC/UKQCD collaborations using domain-wall fermions and the Iwasaki gauge action. Using domain-wall light, strange, and charm quarks and relativistic $b$ quarks, we obtain results at multiple lattice spacings and valence quark masses.