# ICHEP 2020

28 July 2020 to 6 August 2020
virtual conference
Europe/Prague timezone

## Nonperturbative calculations of form factors for exclusive semileptonic B(s) decays

29 Jul 2020, 15:45
15m
virtual conference

#### virtual conference

Talk 05. Quark and Lepton Flavour Physics

### Speaker

Oliver Witzel (University of Colorado Boulder)

### Description

A key ingredient to searches for new physics in the flavor sector are precise theoretical predictions derived from the Standard Model. Due to its large mass and long lifetime processes involving $b$ quarks are of particular interest. Focusing at the nonperturbative QCD contributions, we carry out lattice QCD simulations with the focus on semileptonic $B_{(s)}$ decays. We present results on our determinations of $B_s \to D_s \ell \nu$ and $B_s \to K \ell \nu$ semileptonic form factors with full $q^2$ dependence, discuss the extraction of CKM matrix elements $|V_{cb}|$ and $|V_{ub}|$, as well the determination of $R$-ratios testing the universality of lepton flavors.

Our calculations are based on the set of 2+1 flavor domain wall Iwasaki gauge field configurations generated by the RBC-UKQCD collaboration featuring three lattice spacings of $1/a$ = 1.78, 2.38, and 2.78. Heavy $b$ -quarks are simulated using the relativistic heavy quark action.

### Primary author

Oliver Witzel (University of Colorado Boulder)