2,774 research outputs found

    A New Higgs Boson with Electron-Muon Flavor-Violating Couplings

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    Recently, the CMS Collaboration performed a search on a new resonance decaying to e±μe^\pm\mu^\mp in the mass range of 110 GeV to 160 GeV. The search also hints a possible excess at 146 GeV with a 3.8σ (2.8σ)3.8\sigma~(2.8\sigma) of local (global) significance. Motivated by that, we try to interpret the results in the context of the type-III two-Higgs-doublet-model. We find that the excess is only moderately constrained by low-energy lepton-flavor-violation processes, in particular the μeγ\mu\to e \gamma decay. We also compare the CMS bounds across the entire search region against constraints of μeγ\mu\to e\gamma and μe\mu\to e conversion in nuclei. Our finding indicates that the collider bounds can be superior to those of low-energy processes for the scalar mass between 110 GeV110 \text{ GeV} and 150 GeV150 \text{ GeV}, suggesting the importance of this mass range for future searches.Comment: v1: 7 pages, 2 figures; v2 add compatibility analysis between CMS signal and ATLAS data, matched PLB versio

    Constraints on the χ_(c1) versus χ_(c2) polarizations in proton-proton collisions at √s = 8 TeV

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    The polarizations of promptly produced χ_(c1) and χ_(c2) mesons are studied using data collected by the CMS experiment at the LHC, in proton-proton collisions at √s=8  TeV. The χ_c states are reconstructed via their radiative decays χ_c → J/ψγ, with the photons being measured through conversions to e⁺e⁻, which allows the two states to be well resolved. The polarizations are measured in the helicity frame, through the analysis of the χ_(c2) to χ_(c1) yield ratio as a function of the polar or azimuthal angle of the positive muon emitted in the J/ψ → μ⁺μ⁻ decay, in three bins of J/ψ transverse momentum. While no differences are seen between the two states in terms of azimuthal decay angle distributions, they are observed to have significantly different polar anisotropies. The measurement favors a scenario where at least one of the two states is strongly polarized along the helicity quantization axis, in agreement with nonrelativistic quantum chromodynamics predictions. This is the first measurement of significantly polarized quarkonia produced at high transverse momentum