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Related papers: New physics in $b\to s\ell\ell$ transitions at one…

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Motivated by the recent hints of lepton flavour non-universality in $B$-meson semi-leptonic decays, we study the constraints of perturbative unitarity on the new physics interpretation of the anomalies in $b \to c \ell \bar \nu$ and $b \to…

High Energy Physics - Phenomenology · Physics 2017-10-10 Luca Di Luzio , Marco Nardecchia

We discuss the consequences of deviations from the Standard Model observed in $b\to s\mu^+\mu^-$ transitions for flavour-changing neutral-current processes involving down-type quarks and neutrinos. We work within an effective field theory…

High Energy Physics - Phenomenology · Physics 2022-11-09 Martín Novoa-Brunet

The basic features of quark and lepton mass matrices can be successfully explained by natural minima of a generic potential with dynamical Yukawa fields invariant under the $[\mathrm{SU(3)}]^5\times \mathcal{O}(3)$ flavor symmetry. If this…

High Energy Physics - Phenomenology · Physics 2017-01-18 Andreas Crivellin , Javier Fuentes-Martin , Admir Greljo , Gino Isidori

In the Standard Model (SM), the rare transitions where a bottom quark decays into a strange quark and a pair of light leptons exhibit a potential sensitivity to physics beyond the SM. In addition, the SM embeds Lepton Flavour Universality…

High Energy Physics - Phenomenology · Physics 2018-02-14 Bernat Capdevila , Andreas Crivellin , Sébastien Descotes-Genon , Joaquim Matias , Javier Virto

We present constraints on Wilson coefficients from a combined fit to data from top-quark and beauty-physics measurements within the Standard Model effective field theory. We consider present data on top-quark pair production and decay,…

High Energy Physics - Phenomenology · Physics 2021-05-13 Stefan Bißmann , Cornelius Grunwald , Gudrun Hiller , Kevin Kröninger

$B$ decays proceeding via $b\to c\ell\nu$ transitions with $\ell=e$ or $\mu$ are tree-level processes in the Standard Model. They are used to measure the CKM element $V_{cb}$, as such forming an important ingredient in the determination of…

High Energy Physics - Phenomenology · Physics 2019-01-30 Martin Jung , David M. Straub

Flavour-changing neutral-current processes, such as $b\to s \ell^+\ell^-$, are forbidden at tree level in the Standard Model and hence might receive comparatively large corrections from new particles. This document highlights recent…

High Energy Physics - Experiment · Physics 2023-03-22 M. Santimaria

We present an up-to-date complete model-independent global fit to $b\to s\ell^+\ell^-$ observables that confirms patterns of New Physics able to explain the data. We include the recent LHCb measurements of $R_K$, $R_{K_S}$, $R_{K^{*+}}$,…

High Energy Physics - Phenomenology · Physics 2022-05-04 Marcel Algueró , Bernat Capdevila , Sébastien Descotes-Genon , Joaquim Matias , Martín Novoa-Brunet

Motivated by recent experimental measurements on flavour physics, in tension with Standard Model predictions, we perform an updated analysis of New Physics violating Lepton Flavour Universality, by using the effective Lagrangian approach…

High Energy Physics - Phenomenology · Physics 2019-09-04 Jorge Alda , Jaume Guasch , Siannah Peñaranda

Recent anomalies in decays induced by $b\to c \ell^- \bar\nu_\ell$ transitions raise the question about such phenomena in the $D$ decays induced by $c\to (s,d)\ell^+\nu_\ell$ transitions. In the experimental side, current measurements on…

High Energy Physics - Phenomenology · Physics 2021-07-07 Xue Leng , Xiao-Long Mu , Zhi-Tian Zou , Ying Li

Current experimental information on the charm meson decay observables in which the $c\to s\ell\nu_\ell$ transitions occur is well compatible with the Standard Model predictions. Recent precise lattice calculations of the $D_s$ meson decay…

High Energy Physics - Phenomenology · Physics 2015-05-13 Svjetlana Fajfer , Ivan Nisandzic , Ursa Rojec

In this article we study $b\to s\mu^+\mu^-$ transitions and possible correlations with the anomalous magnetic moment of the muon ($a_\mu$) within two-Higgs-doublet models with generic Yukawa couplings, including the possibility of…

High Energy Physics - Phenomenology · Physics 2022-10-12 Andreas Crivellin , Dario Müller , Christoph Wiegand

The measurements of several lepton flavor universality (LFU) violating observables in the decays induced by the quark level transition $b \to c \tau \bar{\nu}$ provide an inkling of plausible physics beyond the standard model of electroweak…

High Energy Physics - Phenomenology · Physics 2023-05-17 Shabana Khan , Neetu Raj Singh Chundawat , Dinesh Kumar

In supersymmetric grand-unified models, the lepton mixing matrix can possibly affect flavor-changing transitions in the quark sector. We present a detailed analysis of a model proposed by Chang, Masiero and Murayama, in which the…

High Energy Physics - Phenomenology · Physics 2015-05-27 Jennifer Girrbach , Sebastian Jager , Markus Knopf , Waldemar Martens , Ulrich Nierste , Christian Scherrer , Soren Wiesenfeldt

Starting from the general effective hamiltonian relevant to the $b\to s$ transitions, we derive the expressions for the full angular distributions of the $B \to K^{(\ast )} \ell_1 \ell_2$ decay modes, as well as for ${\cal B}(B_s \to…

High Energy Physics - Phenomenology · Physics 2016-09-12 Damir Becirevic , Olcyr Sumensari , Renata Zukanovich Funchal

We propose a one-loop radiative Majorana-type neutrino-mass matrix without any kind of additional symmetries by introducing two leptoquark-like bosons only. In this scenario, we show that the anomaly appearing in the process $b\to…

High Energy Physics - Phenomenology · Physics 2016-12-28 Kingman Cheung , Takaaki Nomura , Hiroshi Okada

In recent years, experiments revealed intriguing hints for new physics (NP) in semi-leptonic $B$ decays. Both in charged current processes, involving $b \to c \tau \nu$ transitions, and in the neutral currents $b\to s\ell^+\ell^-$, a…

High Energy Physics - Phenomenology · Physics 2020-10-19 Andreas Crivellin , Dario Müller , Francesco Saturnino

The experimental measurements on flavour physics, in tension with Standard Model predictions, exhibit large sources of Lepton Flavour Universality violation. We perform an analysis of the effects of the global fits on the Wilson…

High Energy Physics - Phenomenology · Physics 2022-03-22 Jorge Alda , Jaume Guasch , Siannah Penaranda

We consider the possibility that the neutral-current $B$ anomalies are due to radiative corrections generated by Yukawa interactions of quarks and leptons with new vector-like quark and lepton electroweak doublets and new Standard Model…

High Energy Physics - Phenomenology · Physics 2018-12-27 B. Grinstein , S. Pokorski , G. G. Ross

This Thesis presents my personal contributions to two distinct fields, namely the recent experimental anomalies in B-meson decays, and the longstanding quest for a theoretical explanation of lepton masses and mixings, under a unifying…

High Energy Physics - Phenomenology · Physics 2021-11-02 Valerio Gherardi