Recent results on B mixing and decay constants from HPQCD

TL;DR

This paper reviews recent lattice QCD results on B meson mixing parameters and decay constants, providing updated CKM matrix element ratios and branching fractions crucial for testing the Standard Model.

Contribution

It presents new lattice calculations of B meson decay constants and mixing parameters, refining the determination of CKM matrix elements and Standard Model predictions.

Findings

|V_{td}|/|V_{ts}| = 0.214(1)(5)

Br(B_s -> mu^+ mu^-) = 3.19(19) x 10^{-9}

Updated decay constants for B_s mesons

Abstract

We review recent results for B_d and B_s mixing parameters using MILC N_f=2+1 lattices, NRQCD b-quarks and AsqTad light quarks. Latest numbers for decay constants f_B and f_{B_s} are also presented. Combining our lattice results with experimental determinations of the mass differences \Delta M_d and \Delta M_s leads to an important ratio of elements of the CKM matrix, |V_{td}|/|V_{ts}| = 0.214(1)(5) and an updated Standard Model number for the branching fraction Br(B_s -> mu^+ mu^-) = 3.19(19) x 10^{-9}. Preliminary new results for f_{B_s} based on other actions are also described.