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Related papers: Modified lepton couplings and the Cabibbo-angle an…

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Lepton flavour violation and neutrino masses are a signal for new Physics beyond the Standard Model and are deeply related. The minimal extension of the Standard Model to make it include neutrino masses is not satisfactory from a conceptual…

High Energy Physics - Phenomenology · Physics 2011-07-29 J. N. Esteves

Mixing lepton doublets of the Standard Model can lead to lepton flavour asymmetries in the Early Universe. We present a diagrammatic representation of this recently identified source of $CP$ violation and elaborate in detail on the…

High Energy Physics - Phenomenology · Physics 2015-12-09 Bjorn Garbrecht , Ignacio Izaguirre

We discuss a minimal solution to the long-standing $(g-2)_\mu$ anomaly in a simple extension of the Standard Model with an extra $Z'$ vector boson that has only flavor off-diagonal couplings to the second and third generation of leptons,…

High Energy Physics - Phenomenology · Physics 2016-10-21 Wolfgang Altmannshofer , Chien-Yi Chen , P. S. Bhupal Dev , Amarjit Soni

In spite of the large lepton flavour violation (LFV) observed in neutrino oscillations, within the Standard Model, we do \textit{not} expect any visible LFV in the charged lepton sector ($\mu \to e, \gamma$, $\tau \to \mu, \gamma$, etc.).…

High Energy Physics - Phenomenology · Physics 2008-11-26 Antonio Masiero , Sudhir K. Vempati , Oscar Vives

LHCb found hints for physics beyond the standard model in $B\to K^*\mu^+\mu^-$, $B\to K^*\mu^+\mu^-/B\to K^*e^+e^-$ and $B_s\to\phi\mu^+\mu^-$. In addition, the BABAR results for $B\to D^{(*)}\tau\nu$ and the CMS excess in…

High Energy Physics - Phenomenology · Physics 2016-04-20 Andreas Crivellin

A modified neutrino sector could imprint a signature on precision measurements of the quark sector because many such measurements rely on the semi-leptonic decays of the charged currents. Currently, global fits of the determinations of the…

High Energy Physics - Phenomenology · Physics 2023-12-29 Teppei Kitahara , Kohsaku Tobioka

There are four models of tree-level new physics (NP) that can potentially explain the $b\to s \mu^+ \mu^-$ and $b \to c\ell \bar \nu$ anomalies simultaneously. They are the S3, U3, and U1 leptoquarks and a standard-model-like triplet vector…

High Energy Physics - Phenomenology · Physics 2019-07-02 Jacky Kumar

In this review we discuss physics of the lepton sector, the anomalous dipole moment of muon, the charged lepton-flavor violation, and the electric dipole moments of charged leptons, from viewpoints of the minimal supersymmetric standard…

High Energy Physics - Phenomenology · Physics 2009-11-07 J. Hisano

A discrepancy between the experimental and theoretical results was reported for the anomalous magnetic moment of the muon. In leptogenesis scenarios which are due to a decay of right-handed neutrinos, this anomaly leads to large violations…

High Energy Physics - Phenomenology · Physics 2008-05-08 Motoi Endo , Tetsuo Shindou

New sub-GeV vector bosons with couplings to muons but not electrons have been discussed in order to explain the muon's magnetic moment, the gap of high-energy neutrinos in IceCube or the proton radius puzzle. If such a light Z' not only…

High Energy Physics - Phenomenology · Physics 2016-05-11 Julian Heeck

Although the $(g-2)_\mu$ anomaly can be explained by New Physics (NP) involving only muons, a more general flavor structure is usually expected for NP operators in the Standard Model (SM) Effective Field Theory (SMEFT). In particular, if…

High Energy Physics - Phenomenology · Physics 2022-05-30 Julie Pagès

Within $Z^\prime$ models, neutral meson mixing severely constrains beyond the Standard Model (SM) effects in flavour changing neutral current (FCNC) processes. However, in certain regions of the $Z^\prime$ parameter space, the contributions…

High Energy Physics - Phenomenology · Physics 2025-05-01 Andrzej J. Buras , Peter Stangl

It is presented an analysis on lepton flavour violating transitions, leptonic magnetic dipole moments and electric dipole moments in a class of models characterized by the flavour symmetry A4 x Z3 x U(1)_FN, whose choice is motivated by the…

High Energy Physics - Phenomenology · Physics 2009-07-22 Luca Merlo

We have investigated $B \to (K,K^*)(l\bar l,\nu\bar\nu)$ decay channels and predicted some form factor dependent observables (e.g. branching ratio, forward-backward asymmetry and lepton polarization asymmetry) considering new physics…

High Energy Physics - Phenomenology · Physics 2019-12-06 P. Maji , P. Nayek , S. Sahoo

We present an overview of searches fo violation of lepton flavor universality with focus on low energy precision probes using pions, kaons, tau leptons, and nuclear beta decays. The current experimental results are reviewed, the theoretical…

High Energy Physics - Phenomenology · Physics 2022-10-12 Douglas Bryman , Vincenzo Cirigliano , Andreas Crivellin , Gianluca Inguglia

An extension of the Standard Model with $\Gamma_2\simeq S_3$ modular flavor symmetry is presented. We consider the construction of the lepton sector, augmented by two right-handed neutrino states, in the vicinity of the fixed points $\tau =…

High Energy Physics - Phenomenology · Physics 2026-05-21 Zurab Tavartkiladze

Recent measurements of the proton radius using the Lamb shift in muonic hydrogen are troublingly discrepant with values extracted from hydrogen spectroscopy and electron-proton scattering experiments. This discrepancy, which differs by more…

High Energy Physics - Phenomenology · Physics 2017-08-08 Yu-Sheng Liu

New-physics (NP) constraints on first-generation quark-lepton interactions are particularly interesting given the large number of complementary processes and observables that have been measured. Recently, first hints for such NP effects…

High Energy Physics - Phenomenology · Physics 2021-10-29 Andreas Crivellin , Martin Hoferichter , Matthew Kirk , Claudio Andrea Manzari , Luc Schnell

It has been shown that the Cabibbo angle can be predicted in terms of group theoretical quantities, if the dihedral group D14 plays the role of a flavor symmetry. We extend a supersymmetric D14 model to the lepton sector and show that…

High Energy Physics - Phenomenology · Physics 2015-06-04 C. Hagedorn , D. Meloni

Similarity between the weak interaction properties of quarks and leptons has led to suggestions that the origin of lepton mixing angles may be related to those of quarks. In this paper, we present a gauge model based on $SU(2)_L \times…

High Energy Physics - Phenomenology · Physics 2009-11-10 P. H. Frampton , R. N. Mohapatra