545 research outputs found

    Measurement of the branching fraction of J/ψ→ρπJ/\psi\rightarrow\rho\pi at KEDR

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    We present the study of the decay J/ψ→ρπJ/\psi \rightarrow \rho \pi. The results are based on of 5.2 million J/ψJ/\psi events collected by the KEDR detector at VEPP-4M collider. The branching fraction is measured to be B(J/ψ→ρπ)=(2.072±0.017±0.056)⋅10−2\mathcal{B}(J/\psi\rightarrow\rho\pi) = \big(2.072\pm 0.017 \pm 0.056 \big)\cdot 10^{-2} where the first uncertainty is statistical, the second one is systematic. This is the most precise single measurement of this quantity at the moment

    Search for decays of the 125 GeV Higgs boson into a Z boson and a ρ or ϕ meson

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    Decays of the 125 GeV Higgs boson into a Z boson and a ρ^0(770) or ϕ(1020) meson are searched for using proton-proton collision data collected by the CMS experiment at the LHC at √s = 13 TeV. The analysed data set corresponds to an integrated luminosity of 137 fb⁻Âč. Events are selected in which the Z boson decays into a pair of electrons or a pair of muons, and the ρ and ϕ mesons decay into pairs of pions and kaons, respectively. No significant excess above the background model is observed. As different polarization states are possible for the decay products of the Z boson and ρ or ϕ mesons, affecting the signal acceptance, scenarios in which the decays are longitudinally or transversely polarized are considered. Upper limits at the 95% confidence level on the Higgs boson branching fractions into Zρ and Zϕ are determined to be 1.04–1.31% and 0.31–0.40%, respectively, where the ranges reflect the considered polarization scenarios; these values are 740–940 and 730–950 times larger than the respective standard model expectations. These results constitute the first experimental limits on the two decay channels

    Search for the lepton flavor violating decay τ → 3ÎŒ in proton-proton collisions at s \sqrt{\mathrm{s}} = 13 TeV