B -physics anomalies: a guide to combined explanations

Buttazzo, Dario (Physik-Institut, Universität Zürich, CH-8057, Zürich, Switzerland) ; Greljo, Admir (Physik-Institut, Universität Zürich, CH-8057, Zürich, Switzerland) (Faculty of Science, University of Sarajevo, Zmaja od Bosne 33-35, 71000, Sarajevo, Bosnia and Herzegovina) ; Isidori, Gino (Physik-Institut, Universität Zürich, CH-8057, Zürich, Switzerland) ; Marzocca, David (Physik-Institut, Universität Zürich, CH-8057, Zürich, Switzerland)

14 November 2017

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 ×U(2) ℓ 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.


Published in: JHEP 1711 (2017) 044
Published by: Springer/SISSA
DOI: 10.1007/JHEP11(2017)044
arXiv: 1706.07808
License: CC-BY-4.0



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