scholarly journals Searching for lepton flavor universality violation and collider signals from a singly charged scalar singlet

2021 ◽  
Vol 103 (7) ◽  
Author(s):  
Andreas Crivellin ◽  
Fiona Kirk ◽  
Claudio Andrea Manzari ◽  
Luca Panizzi
Keyword(s):  
Charged Scalar ◽  
Lepton Flavor ◽  
Singly Charged ◽  
Scalar Singlet

scholarly journals The singly-charged scalar singlet as the origin of neutrino masses

2021 ◽  
Vol 2021 (5) ◽  
Author(s):  
Tobias Felkl ◽  
Juan Herrero-García ◽  
Michael A. Schmidt
Keyword(s):  
Mass Matrix ◽  
Boson Mass ◽  
Neutrino Masses ◽  
Charged Scalar ◽  
Yukawa Couplings ◽  
Left Handed ◽  
Flavour Violation ◽  
Singly Charged ◽  
Charged Lepton Sector ◽  
Scalar Singlet

Abstract We consider the generation of neutrino masses via a singly-charged scalar singlet. Under general assumptions we identify two distinct structures for the neutrino mass matrix. This yields a constraint for the antisymmetric Yukawa coupling of the singly-charged scalar singlet to two left-handed lepton doublets, irrespective of how the breaking of lepton-number conservation is achieved. The constraint disfavours large hierarchies among the Yukawa couplings. We study the implications for the phenomenology of lepton-flavour universality, measurements of the W-boson mass, flavour violation in the charged-lepton sector and decays of the singly-charged scalar singlet. We also discuss the parameter space that can address the Cabibbo Angle Anomaly.

scholarly journals Reconciling(g−2)μand charged lepton flavor violating processes through a doubly charged scalar

2016 ◽  
Vol 93 (11) ◽  
Author(s):  
Joydeep Chakrabortty ◽  
Pradipta Ghosh ◽  
Subhadeep Mondal ◽  
Tripurari Srivastava
Keyword(s):  
Charged Lepton ◽  
Charged Scalar ◽  
Lepton Flavor ◽  
Doubly Charged

scholarly journals Lepton flavor violation and collider searches in a type I + II seesaw model

2019 ◽  
Vol 79 (11) ◽  
Author(s):  
Manoel M. Ferreira ◽  
Tessio B. de Melo ◽  
Sergey Kovalenko ◽  
Paulo R. D. Pinheiro ◽  
Farinaldo S. Queiroz
Keyword(s):  
Standard Model ◽  
New Physics ◽  
Neutrino Masses ◽  
Type I ◽  
Lepton Flavor Violation ◽  
Charged Scalar ◽  
Lepton Flavor ◽  
Flavor Violation ◽  
The Standard Model ◽  
Doubly Charged

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.

scholarly journals Searching for GeV-scale Majorana Dark Matter: inter spem et metum

2021 ◽  
Vol 2021 (4) ◽  
Author(s):  
Adil Jueid ◽  
Salah Nasri ◽  
Rachik Soualah
Keyword(s):  
Dark Matter ◽  
High Energy ◽  
Lepton Sector ◽  
Charged Scalar ◽  
Order Unity ◽  
Lepton Colliders ◽  
The Standard Model ◽  
Experimental Bound ◽  
Nucleus Scattering ◽  
Scalar Singlet

Abstract We suggest a minimal model for GeV-scale Majorana Dark Matter (DM) coupled to the standard model lepton sector via a charged scalar singlet. We show that there is an anti-correlation between the spin-independent DM-Nucleus scattering cross section (σSI) and the DM relic density for parameters values allowed by various theoretical and experimental constraints. Moreover, we find that even when DM couplings are of order unity, σSI is below the current experimental bound but above the neutrino floor. Furthermore, we show that the considered model can be probed at high energy lepton colliders using e.g. the mono-Higgs production and same-sign charged Higgs pair production.

scholarly journals Doubly charged scalar at the High-Luminosity and High-Energy LHC

2019 ◽  
Vol 34 (27) ◽  
pp. 1950157 ◽  
Author(s):  
Tessio B. de Melo ◽  
Farinaldo S. Queiroz ◽  
Yoxara Villamizar
Keyword(s):  
High Energy ◽  
Beyond The Standard Model ◽  
High Luminosity ◽  
Charged Scalar ◽  
Proton Proton ◽  
Model Studies ◽  
Lepton Flavor ◽  
Lepton Colliders ◽  
Charged Leptons ◽  
Doubly Charged

Doubly charged scalars are common figures in several beyond the Standard Model studies, especially those related to neutrino masses. In this work, we estimate the High-Luminosity (HL-LHC) and High-Energy LHC (HE-LHC) sensitivity to doubly charged scalars assuming that they decay promptly and exclusively into charged leptons. Our study focuses on the fit to the same-sign dilepton mass spectra and it is based on proton–proton collisions at 13 TeV, 14 TeV and 27 TeV with integrated luminosity of [Formula: see text] fb[Formula: see text], 3 ab[Formula: see text] and 15 ab[Formula: see text]. We find that HL-LHC may probe doubly charged scalars masses up to 2.3 TeV, whereas HE-LHC can impressively probe masses up to 3 TeV, conclusively constituting a complementary and important probe to signs of doubly charged scalars in lepton flavor violation decays and lepton–lepton colliders.

A multi-charged particle model with local $U(1)_{\mu - \tau}$ to explain muon $g-2$, flavor physics, and possible collider signature

2021 ◽  
Author(s):  
Nilanjana Kumar ◽  
Takaaki Nomura ◽  
Hiroshi Okada
Keyword(s):  
High Energy Physics ◽  
High Energy ◽  
Particle Model ◽  
Charged Scalar ◽  
Creative Commons ◽  
Lepton Flavor ◽  
Modern Physics ◽  
Z Boson Decays ◽  
Meson Mixing ◽  
Collider Signature

Abstract We consider a model with multi-charged particles including vector-like fermions and a charged scalar under a local $U(1)_{\mu - \tau}$ symmetry. We search for allowed parameter region explaining muon anomalous magnetic moment (muon $g-2$) and $b \to s \ell^+ \ell^-$ anomalies, satisfying constraints from the lepton flavor violations, $Z$ boson decays, meson anti-meson mixing and collider experiments. Carrying out numerical analysis, we explore the typical size of the muon $g-2$ and Wilson coefficients to explain $b \to s \ell^+ \ell^-$ anomalies in our model when all other experimental constraints are satisfied. We then discuss the collider physics of the multicharged vectorlike fermions, considering some benchmark points in the allowed parameter space. Content from this work may be used under the terms of the Creative Commons Attribution 3.0 licence. Any further distribution of this work must maintain attribution to the author(s) and the title of the work, journal citation and DOI. Article funded by SCOAP3 and published under licence by Chinese Physical Society and the Institute of High Energy Physics of the Chinese Academy of Science and the Institute of Modern Physics of the Chinese Academy of Sciences and IOP Publishing Ltd.

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