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arXiv · 1411.3916

Form factors for $\mathrm B_\mathrm s \to \mathrm K \ell ν$ decays in Lattice QCD

Felix Bahr·Fabio Bernardoni·John Bulava·Anosh Joseph·Alberto Ramos·Hubert Simma·Rainer Sommer
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Abstract

We present the current status of the computation of the form factor $f_+ (q^2)$ for the semi-leptonic decay $\mathrm B_\mathrm s \to \mathrm K \ell ν$ by the ALPHA collaboration. We use gauge configurations which were generated as part of the Coordinated Lattice Simulations (CLS) effort. They have $N_\mathrm f=2$ non-perturbatively $O(a)$ improved Wilson fermions, and pion masses down to $\approx 250 \,\mathrm {MeV}$ with $m_πL \geq 4$. The heavy quark is treated in non-perturbative Heavy Quark Effective Theory (HQET). We discuss how to extract the form factors from the correlation functions and present first results for the form factor at $q^2 = 21.23\,\mathrm{GeV}^2$ extrapolated to the continuum. Next-to-leading order terms in HQET and the chiral extrapolation still need to be included in the analysis.

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Felix Bahr, Fabio Bernardoni, John Bulava, Anosh Joseph, Alberto Ramos, Hubert Simma, Rainer Sommer. 2014-11-14. Form factors for $\mathrm B_\mathrm s \to \mathrm K \ell ν$ decays in Lattice QCD. https://arxiv.org/abs/1411.3916

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