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The lepton flavour violating charged lepton decays mu to e + gamma and thermal leptogenesis are analysed in the minimal supersymmetric standard model with see-saw mechanism of neutrino mass generation and soft supersymmetry breaking terms…

High Energy Physics - Phenomenology · Physics 2007-05-23 S. T. Petcov , T. Shindou

A search for new long-lived particles decaying to leptons using proton-proton collision data produced by the CERN LHC at $\sqrt{s}$ = 13 TeV is presented. Events are selected with two leptons (an electron and a muon, two electrons, or two…

High Energy Physics - Experiment · Physics 2022-02-21 CMS Collaboration

This Letter presents a search for a heavy neutral particle decaying into an opposite-sign different-flavor dilepton pair, $e^\pm \mu^\mp$, $e^\pm \tau^\mp$, or $\mu^\pm \tau^\mp$ using 20.3 fb$^{-1}$ of $pp$ collision data at $\sqrt{s} = 8$…

High Energy Physics - Experiment · Physics 2015-07-16 ATLAS Collaboration

In this work, the lepton-number-violating processes in $|\Delta L|=2$ decays of $\Lambda_b^0$ baryon, $\Lambda_b^0 \to p \pi^+\mu^- \mu^-$ and $\Lambda_b^0 \to \Lambda_c^+ \pi^+\mu^- \mu^-$, are investigated for the first time, via an…

High Energy Physics - Phenomenology · Physics 2017-08-02 Jhovanny Mejia-Guisao , Diego Milanes , Nestor Quintero , Jose D. Ruiz-Alvarez

Search results are presented for physics beyond the standard model in final states with two opposite-charge, same-flavor leptons, jets, and missing transverse momentum. The data sample corresponds to an integrated luminosity of 35.9…

High Energy Physics - Experiment · Physics 2018-07-18 CMS Collaboration

Composite-fermion models predict excited quarks and leptons with mass scales which can potentially be observed at high-energy colliders like the LHC; the most recent exclusion limits from the CMS and ATLAS Collaborations corner…

High Energy Physics - Phenomenology · Physics 2021-11-02 S. Biondini , S. Dell'Oro , R. Leonardi , S. Marcocci , O. Panella , M. Presilla , F. Vissani

The search for neutrinoless double beta decay is a rich source for new physics. The observation of this decay will lead to understanding of the absolute mass scale of neutrinos, the Majorana nature of the neutrino (whether the neutrino is…

Nuclear Experiment · Physics 2013-05-16 Lisa J. Kaufman

We investigate the impact of extra leptons on observed tensions in the muon $g-2$ and the first-row CKM unitarity. By introducing a new SU(2)$_L$ doublet lepton and a SU(2)$_L$ triplet lepton, we find that both of the tensions can be…

High Energy Physics - Phenomenology · Physics 2020-08-26 Motoi Endo , Satoshi Mishima

The highly successful Standard Model is not complete. It does not explain the baryonic asymmetry in the Universe, the existence of dark matter or the non-zero masses of the neutrinos. Extensions of the Standard Model that propose the…

High Energy Physics - Experiment · Physics 2022-06-24 Sophie Middleton

We stress the importance of precise measurements of rare decays $K^+\rightarrow\pi^+\nu\bar\nu$, $K_L\rightarrow\pi^0\nu\bar\nu$, $K_{L,S}\to\mu^+\mu^-$ and $K_{L,S}\to\pi^0\ell^+\ell^-$ for the search of new physics (NP). This includes…

High Energy Physics - Phenomenology · Physics 2022-03-21 Jason Aebischer , Andrzej J. Buras , Jacky Kumar

We discuss the results of searches for high-mass narrow resonances decaying into pairs of leptons using pp collisions at 7 TeV delivered by LHC and collected with the CMS detector in 2010 and 2011. These include searches for the Z' bosons…

High Energy Physics - Experiment · Physics 2019-08-13 Gennadiy Kukartsev

We study the rare decays of charged \pi\ mesons, \pi+ to e+ e+ \mu- anti-\nu_\mu\ and \pi+ to e+ \mu- e+ \nu_e, induced by a sterile neutrino N with a mass in the range m_\mu < m_N < m_\pi. The first process violates Lepton Number by two…

High Energy Physics - Phenomenology · Physics 2015-06-04 Gorazd Cvetic , Claudio Dib , C. S. Kim

Since its inception, no decisive departure from the predictions of Standard Model (SM) has been reported. But recently various experiments have observed few hints of possible departure from SM predictions in lepton flavor universality…

High Energy Physics - Phenomenology · Physics 2019-09-06 Lobsang Dhargyal

Heavy neutral leptons (HNLs) with masses around the electroweak scale are expected to be rather long-lived particles, as a result of the observed smallness of the active neutrino masses. In this work, we study long-lived HNLs in $N_R$SMEFT,…

High Energy Physics - Phenomenology · Physics 2022-01-17 Giovanna Cottin , Juan Carlos Helo , Martin Hirsch , Arsenii Titov , Zeren Simon Wang

A search for heavy resonances decaying to a pair of Z bosons is performed using data collected with the CMS detector at the LHC. Events are selected by requiring two oppositely charged leptons (electrons or muons), consistent with the decay…

High Energy Physics - Experiment · Physics 2018-03-09 CMS Collaboration

Supersymmetry is perhaps most effectively probed at the Tevatron through production and decay of weak gauginos. Most of the analyses of weak gaugino observables require electrons or muons in the final state. However, it is possible that the…

High Energy Physics - Phenomenology · Physics 2009-10-31 James D. Wells

A search for compositeness of electrons and muons is presented using a data sample of proton-proton collisions at a center-of-mass energy of sqrt(s) = 8 TeV collected with the CMS detector at the LHC and corresponding to an integrated…

High Energy Physics - Experiment · Physics 2016-04-12 CMS Collaboration

Final states containing charged leptons could provide some of the most distinctive signatures for observing physics beyond the Standard Model. We present searches for new physics using 0.32-0.45 /fb of data accumulated at the Tevatron. No…

High Energy Physics - Experiment · Physics 2009-09-29 Catalin I. Ciobanu

We propose a novel possibility to detect a very distinctive signal with more than four muons originating from pair-produced vector-like leptons decaying to a muon-philic $Z^\prime$ boson. These new particles are good candidates to explain…

High Energy Physics - Phenomenology · Physics 2021-08-18 Junichiro Kawamura , Stuart Raby

The Lepton Portal Dark Matter model, in which dark matter states only coupling to the charged leptons, can explain the excess of the muon anomalous magnetic moment measured by the Muon $g - 2$ experiment. In this paper, we demonstrate that…

High Energy Physics - Phenomenology · Physics 2021-04-08 Yang Bai , Joshua Berger