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arXiv · 1211.5127

Form factors for Lambda_b -> Lambda transitions from lattice QCD

William Detmold·C. -J. David Lin·Stefan Meinel·Matthew Wingate
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Abstract

The rare baryonic decays $Λ_b \to Λμ^+ μ^-$ and $Λ_b \to Λγ$ can complement rare $B$ meson decays in constraining models of new physics. In this work, we calculate the relevant $Λ_b \to Λ$ transition form factors at leading order in heavy-quark effective theory using lattice QCD. Our analysis is based on RBC/UKQCD gauge field ensembles with 2+1 flavors of domain-wall fermions, and with lattice spacings of $a\approx 0.11$ fm and $a\approx 0.08$ fm. We compute appropriate ratios of three-point and two-point correlation functions for a wide range of source-sink separations, and extrapolate to infinite separation in order to eliminate excited-state contamination. We then extrapolate the form factors to the continuum limit and to the physical values of the light-quark masses.

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William Detmold, C. -J. David Lin, Stefan Meinel, Matthew Wingate. 2012-12-19. Form factors for Lambda_b -> Lambda transitions from lattice QCD. https://arxiv.org/abs/1211.5127

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