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arXiv · 2210.06857

$B\pi$-state contamination in $B$-meson observables

Oliver Bar·Alexander Broll·Rainer Sommer
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Abstract

Multi-particle states with additional pions are expected to result in a non-negligible excited-state contamination in lattice simulations. We show that heavy meson chiral perturbation theory can be employed to calculate the contamination due to two-particle $B\pi$ states in various $B$-meson observables like the $B$-meson decay constant and the $BB^*\pi$ coupling. We work in the static limit and to next-to-leading order in the chiral expansion. The $B\pi$ states are found to typically overestimate the observables at the few percent level depending on the size of two currently unknown NLO low-energy coefficients. A strategy to independently measure one of them with the 3-point function of the light axial vector current will be discussed.

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Oliver Bar, Alexander Broll, Rainer Sommer. 2022-10-13. $B\pi$-state contamination in $B$-meson observables. https://arxiv.org/abs/2210.06857

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