A measurement is reported of the ratio of branching fractions R(J/ψ)=B(Bc+→J/ψτ+ντ)/B(Bc+→J/ψμ+νμ), where the τ+ lepton is identified in the decay mode τ+→μ+νμντ. 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/ψτ+ντ 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 /ψτ+ντ)/ B (Bc+ →j /ψμ+νμ). PHYSICAL REVIEW LETTERS, 120(12) [10.1103/PhysRevLett.120.121801].

Measurement of the Ratio of Branching Fractions B (Bc+ →j /ψτ+ντ)/ B (Bc+ →j /ψμ+νμ)

Belloli, N;Borsato, M;Calvi, M;Carniti, P;Cassina, L;Fazzini, D;Gotti, C;Grillo, L;Khanji, B;Martinelli, M;Matteuzzi, C;Petruzzo, M;
2018

Abstract

A measurement is reported of the ratio of branching fractions R(J/ψ)=B(Bc+→J/ψτ+ντ)/B(Bc+→J/ψμ+νμ), where the τ+ lepton is identified in the decay mode τ+→μ+νμντ. 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/ψτ+ντ 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.
Articolo in rivista - Articolo scientifico
Physics and Astronomy (all)
English
2018
120
12
121801
none
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 /ψτ+ντ)/ B (Bc+ →j /ψμ+νμ). PHYSICAL REVIEW LETTERS, 120(12) [10.1103/PhysRevLett.120.121801].
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Utilizza questo identificativo per citare o creare un link a questo documento: https://hdl.handle.net/10281/199567
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