at BaBar: new physics searches with lepton flavor violation, lepton universality, or final states with τ leptons

2011 ◽  
Vol 218 (1) ◽  
pp. 77-82
Author(s):  
E. Guido
2020 ◽  
Vol 35 (19) ◽  
pp. 2030007
Author(s):  
Manolis Kargiantoulakis

The Mu2e experiment will search for the neutrino-less conversion of a muon into an electron in the field of an aluminum nucleus. An observation would be the first signal of charged lepton flavor violation and de facto evidence for new physics beyond the Standard Model. The clean signature of the conversion process offers an opportunity for a powerful search: Mu2e will probe four orders of magnitude beyond current limits, with real discovery potential over a wide range of well-motivated new physics models. This goal requires an integrated system of solenoids that will create the most intense muon beam in the world, and suppression of all possible background sources. The Mu2e components are currently being constructed, with the experiment planned to begin operations in the Fermilab Muon Campus within the next few years.


2006 ◽  
Vol 21 (27) ◽  
pp. 5652-5659 ◽  
Author(s):  
ANTONIO PICH

Precise measurements of the τ lepton properties provide stringent tests of the Standard Model structure and accurate determinations of its parameters. We overview the present status of a few selected topics: lepton universality, QCD tests and the determination of αs, msand |Vus| from hadronic τ decays, and lepton flavor violation phenomena.


2015 ◽  
Vol 2015 ◽  
pp. 1-22 ◽  
Author(s):  
A. Vicente

Most extensions of the Standard Model lepton sector predict large lepton flavor violating rates. Given the promising experimental perspectives for lepton flavor violation in the next few years, this generic expectation might offer a powerful indirect probe to look for new physics. In this review we will cover several aspects of lepton flavor violation in supersymmetric models beyond the Minimal Supersymmetric Standard Model. In particular, we will concentrate on three different scenarios: high-scale and low-scale seesaw models as well as models withR-parity violation. We will see that in some cases the LFV phenomenology can have characteristic features for specific scenarios, implying that dedicated studies must be performed in order to correctly understand the phenomenology in nonminimal supersymmetric models.


2021 ◽  
Vol 81 (9) ◽  
Author(s):  
Tong Li ◽  
Michael A. Schmidt ◽  
Chang-Yuan Yao ◽  
Man Yuan

AbstractAny observation of charged lepton flavor violation (CLFV) implies the existence of new physics beyond the SM in charged lepton sector. CLFV interactions may also contribute to the muon magnetic moment and explain the discrepancy between the SM prediction and the recent muon $$g-2$$ g - 2 precision measurement at Fermilab. We consider the most general SM gauge invariant Lagrangian of $$\Delta L=0$$ Δ L = 0 bileptons with CLFV couplings and investigate the interplay of low-energy precision experiments and colliders in light of the muon magnetic moment anomaly. We go beyond previous work by demonstrating the sensitivity of the LHC, the MACE experiment, a proposed muonium-antimuonium conversion experiment, and a muon collider. Currently-available LHC data is already able to probe unexplored parameter space via the CLFV process $$pp\rightarrow \gamma ^*/Z^*\rightarrow \ell _1^\pm \ell _1^\pm \ell _2^\mp \ell _2^\mp $$ p p → γ ∗ / Z ∗ → ℓ 1 ± ℓ 1 ± ℓ 2 ∓ ℓ 2 ∓ .


2019 ◽  
Vol 79 (11) ◽  
Author(s):  
Manoel M. Ferreira ◽  
Tessio B. de Melo ◽  
Sergey Kovalenko ◽  
Paulo R. D. Pinheiro ◽  
Farinaldo S. Queiroz

AbstractNeutrinos are massless in the Standard Model. The most popular mechanism to generate neutrino masses are the type I and type II seesaw, where right-handed neutrinos and a scalar triplet are augmented to the Standard Model, respectively. In this work, we discuss a model where a type I + II seesaw mechanism naturally arises via spontaneous symmetry breaking of an enlarged gauge group. Lepton flavor violation is a common feature in such setup and for this reason, we compute the model contribution to the $$\mu \rightarrow e\gamma $$μ→eγ and $$\mu \rightarrow 3e$$μ→3e decays. Moreover, we explore the connection between the neutrino mass ordering and lepton flavor violation in perspective with the LHC, HL-LHC and HE-LHC sensitivities to the doubly charged scalar stemming from the Higgs triplet. Our results explicitly show the importance of searching for signs of lepton flavor violation in collider and muon decays. The conclusion about which probe yields stronger bounds depends strongly on the mass ordering adopted, the absolute neutrino masses and which much decay one considers. In the 1–5 TeV mass region of the doubly charged scalar, lepton flavor violation experiments and colliders offer orthogonal and complementary probes. Thus if a signal is observed in one of the two new physics searches, the other will be able to assess whether it stems from a seesaw framework.


2020 ◽  
Vol 2020 (10) ◽  
Author(s):  
Fabio Bossi ◽  
Paolo Ciafaloni

Abstract Lepton Flavor Violating (LFV) processes are clear signals of physics beyond the Standard Model. We investigate the possibility of measuring this kind of processes at present and foreseeable future muon-electron colliders, taking into account present day bounds from existing experiments. As a model of new physics we consider a Z’ boson with a Ut(1) gauge symmetry and generic couplings. Processes that violate lepton flavor by two units seem to be particularly promising.


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