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) x 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.

B-physics anomalies: a guide to combined explanations / Buttazzo, Dario; Greljo, Admir; Isidori, Gino; Marzocca, David. - In: JOURNAL OF HIGH ENERGY PHYSICS. - ISSN 1029-8479. - 2017:11(2017), pp. 1-33. [10.1007/jhep11(2017)044]

B-physics anomalies: a guide to combined explanations

Admir Greljo;David Marzocca
2017-01-01

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) x 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.
2017
2017
11
1
33
44
10.1007/jhep11(2017)044
https://arxiv.org/abs/1706.07808
Buttazzo, Dario; Greljo, Admir; Isidori, Gino; Marzocca, David
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Utilizza questo identificativo per citare o creare un link a questo documento: https://hdl.handle.net/20.500.11767/132020
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