![]() This paper summarizes the searches for LFV decays performed with the ATLAS detector using pp collision data collected at the center-of-mass energy of 13 TeV. Recently, new models have proposed LFV decays of the Higgs or heavier bosons as a necessary ingredient to explain the flavor anomalies observed by LHCb. The addition of an extra U(1) gauge symmetry to the SM results in a massive neutral Z′ boson that could also decay through LFV processes. Other models with more than one Higgs doublet, composite Higgs or warped extra dimension models predict LFV decays of the Higgs boson, too. This feature opens the possibility of detecting indirectly scenarios with very high m SUSY via LFV Higgs boson decays. In particular Minimal Supersymmetric SM scenarios with very high energy scale of the SUSY particle masses m SUSY present a non-decoupling behavior of the Higgs boson partial widths in two leptons of different flavor, with respect to m SUSY. For instance, LFV decays of the Z boson are predicted by models with heavy neutrinos, extended gauge models and supersymmetry (SUSY), which also allows for LFV decays of the Higgs boson. A possible sign of such processes would be the lepton-flavor-violation (LFV) in decays of heavy bosons, such as well-established Z and Higgs bosons or even not-yet-discovered bosons ( Z′, additional Higgs bosons, etc).ĭirect LFV processes are forbidden in the SM but are allowed in its many extensions. All results are consistent, within their uncertainties, with the expectations for the Standard Model Higgs boson.The search for processes beyond the Standard Model (SM) is one of the goals of the physics programme at the Large Hadron Collider (LHC) at CERN. The measured Higgs boson properties include its mass, signal strength relative to the standard model prediction, signal strength modifiers for different Higgs boson production modes, coupling modifiers to fermions and bosons, effective coupling modifiers to photons and gluons, simplified template cross sections, fiducial cross sections. We perform a model-independent global fit to \(b\rightarrow s\ell ^ \ell ^-\) observables to confirm existing New Physics (NP) patterns (or scenarios) and to identify new ones emerging from the inclusion of the updated LHCb and Belle measurements of \(R_K\) and \(R_,\mu$. The H → γ*γ → μμγ and H → Zγ →ℓℓγ analyses are combined for mH =125GeV, obtaining an observed (expected) 95% confidence level upper limit of 3.9 (2.0) times the standard model cross section.Ī preprint version of the article is available at ArXiv. The observed limits on cross section times the corresponding branching fractions vary between 1.4 and 4.0 (6.1 and 11.4) times the standard model cross section for H → γ*γ → μμγ (H → Zγ → ℓℓγ) in the 120–130 GeV mass range of the ℓℓγ system. Limits are set on the cross section for a standard model Higgs boson decaying to opposite-sign electron or muon pairs and a photon. No significant excess above the background prediction has been found. The analysis is performed using a data set recorded by the CMS experiment at the LHC from proton-proton collisions at a center-of-mass energy of 13 TeV, corresponding to an integrated luminosity of 35.9 fb−1. Higgs boson decays to a Z boson and a photon (H → Zγ → ℓℓγ, ℓ = e or μ), or to two photons, one of which has an internal conversion into a muon pair (H → γ*γ → μμγ) were considered. A search for a Higgs boson decaying into a pair of electrons or muons and a photon is described.
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