The ratio between the B-c(+) -> J/psi tau(+)nu(tau) and B-c(+) -> J/psi mu(+nu)(mu) branching fractions is measured using a data sample of proton-proton collisions collected by CMS at a center-of-mass energy of 13 TeV in the years 2016-2018 and corresponding to an integrated luminosity of 138 fb(-1). The J/psi meson is identified through its J/psi -> mu(+)mu(-) decay and the tau lepton is reconstructed in the hadronic three-prong final state. The measured ratio of branching fractions in this tau decay mode, R-J/psi(had) = 1.04(-0.44)(+0.50), is combined with the previous analysis based on the tau(+) -> mu(+)nu(mu)(nu) over bar (tau) leptonic decay channel, leading to R-J/psi = 0.49 +/- 0.26. As this result is consistent with the standard model prediction of 0.258 +/- 0.004, no evidence of lepton flavor universality violation is found.

Chekhovsky, V., Hayrapetyan, A., Makarenko, V., Tumasyan, A., Adam, W., Andrejkovic, J.W., et al. (2026). Measurement of the ratio of the Bc+ → J/ψτ+ντ and Bc+ → J/ψμ+νμ branching fractions using three-prong τ lepton decays. PHYSICAL REVIEW D, 113(11) [10.1103/mw5c-5rw3].

Measurement of the ratio of the Bc+ → J/ψτ+ντ and Bc+ → J/ψμ+νμ branching fractions using three-prong τ lepton decays

Ciocci, M. A.;Turini, N.;
2026-01-01

Abstract

The ratio between the B-c(+) -> J/psi tau(+)nu(tau) and B-c(+) -> J/psi mu(+nu)(mu) branching fractions is measured using a data sample of proton-proton collisions collected by CMS at a center-of-mass energy of 13 TeV in the years 2016-2018 and corresponding to an integrated luminosity of 138 fb(-1). The J/psi meson is identified through its J/psi -> mu(+)mu(-) decay and the tau lepton is reconstructed in the hadronic three-prong final state. The measured ratio of branching fractions in this tau decay mode, R-J/psi(had) = 1.04(-0.44)(+0.50), is combined with the previous analysis based on the tau(+) -> mu(+)nu(mu)(nu) over bar (tau) leptonic decay channel, leading to R-J/psi = 0.49 +/- 0.26. As this result is consistent with the standard model prediction of 0.258 +/- 0.004, no evidence of lepton flavor universality violation is found.
2026
Chekhovsky, V., Hayrapetyan, A., Makarenko, V., Tumasyan, A., Adam, W., Andrejkovic, J.W., et al. (2026). Measurement of the ratio of the Bc+ → J/ψτ+ντ and Bc+ → J/ψμ+νμ branching fractions using three-prong τ lepton decays. PHYSICAL REVIEW D, 113(11) [10.1103/mw5c-5rw3].
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Utilizza questo identificativo per citare o creare un link a questo documento: https://hdl.handle.net/11365/1324424