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arXiv · 1706.07808

B-physics anomalies: a guide to combined explanations

Dario Buttazzo·Admir Greljo·Gino Isidori·David Marzocca
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Abstract

Motivated by additional experimental hints of Lepton Flavour Universality violation in B decays, both in charged- and in neutral-current processes, we analyse the ingredients necessary to provide a combined description of these phenomena. By means of an Effective Field Theory (EFT) approach, based on the hypothesis of New Physics coupled predominantly to the third generation of left-handed quarks and leptons, we show how this is possible. We demonstrate, in particular, how to solve the problems posed by electroweak precision tests and direct searches with a rather natural choice of model parameters, within the context of a $U(2)_q \times U(2)_\ell$ flavour symmetry. We further exemplify the general EFT findings by means of simplified models with explicit mediators in the TeV range: coloured scalar or vector leptoquarks and colour-less vectors. Among these, the case of an $SU(2)_L$-singlet vector leptoquark emerges as a particularly simple and successful framework.

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Dario Buttazzo, Admir Greljo, Gino Isidori, David Marzocca. 2017-10-18. B-physics anomalies: a guide to combined explanations. https://doi.org/10.1007/jhep11(2017)044

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