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.
A measurement is reported of the ratio of branching fractions R(J/psi) = B(B-c(+) -> J/psi tau(+)nu(tau))/B(B-c(+) -> J/psi mu(+)nu(mu)), where the tau(+) lepton is identified in the decay mode tthorn tau(+) -> mu(+)nu(mu)(nu) over bar (tau). 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 B-c(+) -> J/psi tau(+)nu(tau) at a significance of 3 standard deviations corrected for systematic uncertainty, and the ratio of the branching fractions is measured to be R(J/psi) = 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.
Measurement of the Ratio of Branching Fractions B(B-c(+) -> J/psi tau(+)nu(tau))/B(B-c(+) -> J/psi mu(+)nu(mu))
Lusiani, A.Membro del Collaboration Group
;Morello, M. J.Membro del Collaboration Group
;
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.File | Dimensione | Formato | |
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PhysRevLett.120.121801-scoap3.pdf
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