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While the LHC has not directly observed any new particle so far, experimental results from LHCb, BELLE and BABAR point towards the violation of lepton flavour universality in $b\to s\ell^{+}\ell^{-}$ and $b\to c\ell\nu$. In this context,…

High Energy Physics - Phenomenology · Physics 2018-06-13 Dario Müller

We study the implications of the observed excess in $B^+ \to K^+ \nu \bar{\nu}$ under the assumption of Rank-One Flavour Violation, i.e. that New Physics couples to a single specific direction in flavour space. By varying this direction we…

High Energy Physics - Phenomenology · Physics 2024-11-05 David Marzocca , Marco Nardecchia , Alfredo Stanzione , Claudio Toni

The possibility that the interactions of the third generation of quarks and leptons may violate universality by a small amount remains an open experimental question. The model of Li and Ma, which naturally accommodates such violations, is…

High Energy Physics - Phenomenology · Physics 2009-10-22 T. G. Rizzo

B-decays mediated by both charged currents and neutral currents have provided hints of violation of lepton flavour universality. By assuming an explanation of these anomalies in terms of new physics at the TeV scale affecting the third…

High Energy Physics - Phenomenology · Physics 2018-08-07 Ferruccio Feruglio

Flavor symmetries that explain masses and mixings of the standard model fermions dictate flavor patterns for the couplings of scalar and vector leptoquarks to the standard model fermions. A generic feature is that couplings to…

High Energy Physics - Phenomenology · Physics 2017-01-04 Gudrun Hiller , Dennis Loose , Kay Schönwald

Significant deviations from Standard Model (SM) predictions have been observed in $ b \to s \mu^+ \mu^-$ decays and in the muon $g-2$. Scalar leptoquark extensions of the SM are known to be able to address these anomalies, but generically…

High Energy Physics - Phenomenology · Physics 2021-10-15 Admir Greljo , Peter Stangl , Anders Eller Thomsen

We investigate the prospects for detection of lepton flavour violation in sparticle production and decays at a Linear Collider (LC), in models guided by neutrino oscillation data. We consider both slepton pair production and sleptons…

High Energy Physics - Phenomenology · Physics 2015-05-28 E. Carquin , J. Ellis , M. E. Gomez , S. Lola

We study the phenomenology of a particular leptoquark extension of the Standard Model (SM), namely the doublet-singlet scalar leptoquark extension of the SM (DSL-SM). Besides generating Majorana mass for neutrinos, these leptoquarks…

High Energy Physics - Phenomenology · Physics 2023-01-16 Snehashis Parashar , Anirban Karan , Avnish , Priyotosh Bandyopadhyay , Kirtiman Ghosh

Vector leptoquarks can address the lepton flavor universality anomalies in decays associated with the $b \to c \ell \nu$ and $b \to s \ell \ell$ transitions, as observed in recent years. Generically, these leptoquarks yield new sources of…

High Energy Physics - Phenomenology · Physics 2020-06-24 Wolfgang Altmannshofer , Stefania Gori , Hiren H. Patel , Stefano Profumo , Douglas Tuckler

We explore the possibility that lepton family numbers and baryon number are such good symmetries of Nature because they are the global remnant of a spontaneously broken gauge symmetry. An almost arbitrary linear combination of these…

High Energy Physics - Phenomenology · Physics 2020-01-15 Wolfgang Altmannshofer , Joe Davighi , Marco Nardecchia

Motivated by the recent measurement of the lepton flavour nonuniversality ratio $R_{K^*}$ by the LHCb Collaboration, we study the implications of vector leptoquarks on the observed anomalies associated with the $\bar B \to \bar K^* l^+ l^-$…

High Energy Physics - Phenomenology · Physics 2018-08-01 Suchismita Sahoo , Rukmani Mohanta

A search for new bosons possessing couplings to lepton-quark pairs is performed in the H1 experiment at HERA using 1994 to 1997 data corresponding to an integrated luminosity of 37pb^-1. First generation leptoquarks (LQs) are searched in…

High Energy Physics - Experiment · Physics 2008-11-26 H1 Collaboration , C. Adloff

Lepton flavour violation (LFV), and lepton flavour university violation (LFUV), are striking signatures of beyond the Standard Model (BSM) physics. Recent searches for these at the ATLAS and CMS experiments are presented, using…

High Energy Physics - Experiment · Physics 2024-05-21 Holly Pacey

We introduce the CP violating scalar leptoquark $S_3$ to explain the measured values of the lepton universality ratios $R_{K^{(*)}}$. We derive constraints on the CP-even and CP-odd components of the leptoquark Yukawa couplings stemming…

High Energy Physics - Phenomenology · Physics 2021-09-10 Nejc Košnik , Aleks Smolkovič

We construct an extension of the Standard Model with a scalar leptoquark $\phi \sim (3,1,-\tfrac13)$ and the discrete flavour symmetry $G_f=D_{17}\times Z_{17}$ to explain anomalies observed in charged-current semi-leptonic $B$ meson decays…

High Energy Physics - Phenomenology · Physics 2023-10-23 Innes Bigaran , Tobias Felkl , Claudia Hagedorn , Michael A. Schmidt

Recent searches for first-generation leptoquarks and heavy right-handed $W_R$ bosons have seen excesses in final states with electrons and jets. A bizarre property of these excesses is that they appear to violate lepton universality. With…

High Energy Physics - Phenomenology · Physics 2015-10-05 Joshua Berger , Jeff Asaf Dror , Wee Hao Ng

We extend the $SU(3)_C \times SU(3)_L \times U(1)_X$ model with neutral leptons (331LHN) by introducing scalar leptoquarks. We determine the particle content of the leptoquark multiplets and their Yukawa interactions with fermions. We find…

High Energy Physics - Phenomenology · Physics 2026-04-15 D. T. Binh , V. H. Binh , H. T. Hung , Duong Van Loi

The measurements of the ratios $R_{K^{(*)}}$ along with $R_{D^{(*)}}$ hint towards lepton flavor non universality which is in disagreement with the standard model. In this work, we reanalyze the four new physics models, which are widely…

High Energy Physics - Phenomenology · Physics 2019-08-27 Ashutosh Kumar Alok , Jacky Kumar , Dinesh Kumar , Ruchi Sharma

We study the implications of single leptoquark extensions of the Standard Model (SM) under the assumption that their enhanced Yukawa sectors are invariant under global Abelian flavour symmetries already present in SM mass terms. Such…

High Energy Physics - Phenomenology · Physics 2022-10-19 Ivo de Medeiros Varzielas , Jim Talbert

We interpret the recent hints for lepton flavor universality violation in rare $B$ meson decays. Based on a model-independent effective Hamiltonian approach, we determine regions of new physics parameter space that give a good description…

High Energy Physics - Phenomenology · Physics 2018-05-04 Wolfgang Altmannshofer , Peter Stangl , David M. Straub