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We consider the leptonic and semileptonic (SL) lepton flavour violating (LFV) decays of the charged leptons in the minimal supersymmetric standard model (MSSM). The formalism for evaluation of branching fractions for the SL LFV…

High Energy Physics - Phenomenology · Physics 2008-11-26 Takeshi Fukuyama , Amon Ilakovac , Tatsuru Kikuchi

The concept of lepton flavour universality (LFU), according to which the three lepton families are equivalent except for their masses, is a cornerstone prediction of the Standard Model (SM). LFU can be violated in models beyond the SM by…

High Energy Physics - Experiment · Physics 2019-05-22 Elena Graverini

Minimal dark matter is an attractive candidate for dark matter because it is stabilized without the need to impose additional symmetries. It is known that the $SU(2)_L$ quintuplet fermion can serve as a minimal dark matter candidate, with…

High Energy Physics - Phenomenology · Physics 2025-03-26 Takashi Toma

Neutrino oscillations give clear evidence for non-vanishing neutrino masses and lepton-flavor violation (LFV) in the neutrino sector. This provides strong motivation to search for signals of LFV also in the charged lepton sector, and to…

High Energy Physics - Phenomenology · Physics 2009-11-07 F. Deppisch , H. Päs , A. Redelbach , R. Rückl , Y. Shimizu

In the family grand unification models (fGUTs), we propose that gauge U(1)'s beyond the minimal GUT gauge group are family gauge symmetries. For the symmetry $L_\mu-L_\tau$, i.e. $Q_{2}-Q_{3}$ in our case, to be useful for the LHC anomaly,…

High Energy Physics - Phenomenology · Physics 2020-07-29 Paul H. Frampton , Sin Kyu Kang , Jihn E. Kim , Soonkeon Nam

With the start of the LHC, interest in electroweak scale models for the neutrino mass has grown. In this letter, we review two specific models that simultaneously explain neutrino masses and provide a suitable DM candidate. We discuss the…

High Energy Physics - Phenomenology · Physics 2011-11-10 Yasaman Farzan

In this Letter we explore, for the first time, the constraints on lepton flavor violating (LFV) dark matter (DM) scenarios via the astrophysical photons and positrons, including both the annihilation and decay modes, ${\tt DM(+DM)}\to e^\pm…

High Energy Physics - Phenomenology · Physics 2026-02-06 Jin-Han Liang , Yi Liao , Xiao-Dong Ma

The left-right symmetric model (LRSM) could not only restore parity of the weak interaction, but also provide natural explanations of the tiny active neutrino masses via the seesaw mechanisms. The $SU(2)_R$-breaking scalar $H_3$ can induce…

High Energy Physics - Phenomenology · Physics 2026-01-01 Shufang Qiang , Peiwen Wu , Yongchao Zhang

The Littlest Higgs Model with T-Parity (LHT) contains new sources of flavor and CP violation both in the quark and lepton sector. These have their origin in interactions of ordinary fermions with mirror fermions mediated by new heavy gauge…

High Energy Physics - Phenomenology · Physics 2007-10-11 Bjoern Duling

We show how gauge coupling unification is successfully implemented through non-supersymmetric grand unified theory, $SO(10)\times G_f (~G_f=S_4, SO(3)_f, SU(3)_f)$, using low-scale flavor symmetric model of the type $SU(2)_L\times U(1)_Y$ $…

High Energy Physics - Phenomenology · Physics 2011-05-20 Mina K. Parida , Pradip K. Sahu , Kalpana Bora

Minimal Flavour Violation in its strong or weak versions, based on $U(3)^3$ and $U(2)^3$ respectively, allows suitable extensions of the Standard Model at the TeV scale to comply with current flavour constraints in the quark sector. Here we…

High Energy Physics - Phenomenology · Physics 2016-01-27 Riccardo Barbieri , Fabrizio Senia

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

Despite strong experimental evidences for their conservation at low energies, the baryon $B$ and lepton $L$ numbers are not expected to be absolute symmetries. Already violated in the Standard Model (SM) by non-perturbative effects (tiny at…

High Energy Physics - Phenomenology · Physics 2013-09-18 Gauthier Durieux

Recent results from Super Kamiokande suggest $\nu_\mu-\nu_\tau$ mixing and hence lepton flavor violation. In supersymmetric models, this flavor violation may have implications for the pattern of slepton masses and mixings. Possible signals…

High Energy Physics - Phenomenology · Physics 2008-11-26 I. Hinchliffe , F. E. Paige

In this study, we apply LHC data to constrain the extension of the Standard Model by an anomaly-free $U(1)_{L_\mu-L_\tau}$ gauge group; this model contains a new gauge boson ($Z^\prime$) and a scalar dark matter particle ($\phi_{\rm DM}$).…

High Energy Physics - Phenomenology · Physics 2019-03-06 Manuel Drees , Meng Shi , Zhongyi Zhang

We look for minimal extensions of Standard Model with vector like fermions leading to precision unification of gauge couplings. Constraints from proton decay, Higgs stability and perturbativity are considered. The simplest models contain…

High Energy Physics - Phenomenology · Physics 2018-05-17 Biplob Bhattacherjee , Pritibhajan Byakti , Ashwani Kushwaha , Sudhir K Vempati

Motivated by the recent discovery of the Higgs boson at m_h = 126 GeV and also by the non-observation of superparticles at the LHC, high-scale SUSY, where the superparticles are as heavy as O(10) TeV, has been recently proposed. We study…

High Energy Physics - Phenomenology · Physics 2015-06-16 Takeo Moroi , Minoru Nagai , Tsutomu T. Yanagida

Attention is called to potentially dangerous lepton-flavor violation (LFV) induced by the D-terms of additional U(1) flavor-dependent gauge symmetries in supersymmetric models. In such models, LFV persists despite an arbitrarily high scale…

High Energy Physics - Phenomenology · Physics 2009-11-07 Brandon Murakami , Kazuhiro Tobe , James D. Wells

Two topics have recently risen to prominence within the ongoing searches of beyond-Standard Model effects in $b$ and $c$ decays: observables that test lepton flavor universality (LFU) as well as lepton flavor violation (LFV). A coherent set…

High Energy Physics - Phenomenology · Physics 2023-10-10 Diego Guadagnoli , Patrick Koppenburg

In the absence of a fundamental principle preventing charged lepton flavour violation, one expects that extensions of the Standard Model accommodating neutrino masses and mixings should also allow for charged lepton flavour violating…

High Energy Physics - Phenomenology · Physics 2015-06-03 A. Abada