A measurement is reported of the ratio of branching fractions R(J/ψ) = B(Bc+ → J/ψ τ+ ν_τ)/B(Bc+ → J/ψ μ+ ν_μ), where the τ+ lepton is identified in the decay mode τ+ → μ+ ν_μ anti-ν_τ. This analysis uses a sample of proton-proton collision data corresponding to 3.0 fb^−1 of integrated luminosity recorded with the LHCb experiment at center-of-mass energies of 7 and 8 TeV. A signal is found for the decay Bc+ → J/ψ τ+ ν_τ at a significance of 3 standard deviations corrected for systematic uncertainty, and the ratio of the branching fractions is measured to be R(J/ψ) = 0.71 ± 0.17 (stat) ± 0.18 (syst). This result lies within 2 standard deviations above the range of central values currently predicted by the standard model.

Aaij, R., Adeva, B., Adinolfi, M., Ajaltouni, Z., Akar, S., Albrecht, J., et al. (2018). Measurement of the Ratio of Branching Fractions B(Bc+ → J/ψ τ+ ν_τ)/B(Bc+ → J/ψ μ+ ν_μ). PHYSICAL REVIEW LETTERS, 120(12), 1-10 [10.1103/PhysRevLett.120.121801].

Measurement of the Ratio of Branching Fractions B(Bc+ → J/ψ τ+ ν_τ)/B(Bc+ → J/ψ μ+ ν_μ)

Betti, F.;Capriotti, L.;Carbone, A.;Ferrari, F.;Galli, D.;Marconi, U.;Patrignani, C.;Perazzini, S.;Pisani, F.;Vagnoni, V.;Zucchelli, S.
2018

Abstract

A measurement is reported of the ratio of branching fractions R(J/ψ) = B(Bc+ → J/ψ τ+ ν_τ)/B(Bc+ → J/ψ μ+ ν_μ), where the τ+ lepton is identified in the decay mode τ+ → μ+ ν_μ anti-ν_τ. This analysis uses a sample of proton-proton collision data corresponding to 3.0 fb^−1 of integrated luminosity recorded with the LHCb experiment at center-of-mass energies of 7 and 8 TeV. A signal is found for the decay Bc+ → J/ψ τ+ ν_τ at a significance of 3 standard deviations corrected for systematic uncertainty, and the ratio of the branching fractions is measured to be R(J/ψ) = 0.71 ± 0.17 (stat) ± 0.18 (syst). This result lies within 2 standard deviations above the range of central values currently predicted by the standard model.
2018
Aaij, R., Adeva, B., Adinolfi, M., Ajaltouni, Z., Akar, S., Albrecht, J., et al. (2018). Measurement of the Ratio of Branching Fractions B(Bc+ → J/ψ τ+ ν_τ)/B(Bc+ → J/ψ μ+ ν_μ). PHYSICAL REVIEW LETTERS, 120(12), 1-10 [10.1103/PhysRevLett.120.121801].
Aaij, R.; Adeva, B.; Adinolfi, M.; Ajaltouni, Z.; Akar, S.; Albrecht, J.; Alessio, F.; Alexander, M.; Alfonso Albero, A.; Ali, S.; Alkhazov, G.; Alvar...espandi
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Utilizza questo identificativo per citare o creare un link a questo documento: https://hdl.handle.net/11585/634494
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