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arXiv · 2012.04323

Nonperturbative calculations of form factors for exclusive semileptonic $B_{(s)}$ decays

Jonathan M. Flynn·Ryan C. Hill·Andreas Jüttner·Amarjit Soni·J. Tobias Tsang·Oliver Witzel
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Abstract

Precise theoretical predictions derived from the Standard Model are a key ingredient in searches for new physics in the flavor sector. The large mass and long lifetime of the $b$ quark make processes involving $b$ quarks of particular interest. We use lattice simulations to perform nonperturbative QCD calculations for semileptonic $B_{(s)}$ decays. We present results from our determinations of $B_s\to D_s \ell \nu$ and $B_s\to K \ell \nu$ semileptonic form factors and provide an outlook for our $B\to \pi\ell\nu$ calculation. In addition we discuss the determination of $R$-ratios testing lepton-flavor universality and suggest use of an improved ratio. 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 $2.79\,\text{GeV}$. Heavy $b$-quarks are simulated using the relativistic heavy quark action.

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Jonathan M. Flynn, Ryan C. Hill, Andreas Jüttner, Amarjit Soni, J. Tobias Tsang, Oliver Witzel. 2020-12-08. Nonperturbative calculations of form factors for exclusive semileptonic $B_{(s)}$ decays. https://arxiv.org/abs/2012.04323

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