The first evidence for the decay B- -> D**(0)tau(-)(nu) over bar (tau) is obtained using proton-proton collision data collected by the LHCb experiment, corresponding to an integrated luminosity of 9 fb(-1), at centre-of-mass energies of 7, 8, and 13 TeV. Here, the D**0 meson represents any of the three excited charm mesons D-1(2420)(0), D*(2)(2460)(0), and D'(1)(2400)(0). The B- -> D**(0)tau(-)(nu) over bar (tau) signal is measured with a significance of 3.5 sigma, including systematic uncertainties. The combined branching fraction B(B- -> D**(0)(1,2) tau(-)(nu) over bar (tau)) x B(D**(0)(1,2) -> D*(+) pi(-)), where D**(0)(1,2) denotes both D-1(2420)(0) and D*(2)(2460)(0) contributions, is measured to be [0.051 +/- 0.013(stat) +/- 0.006(syst) +/- 0.009(ext)]%, where the last uncertainty reflects that of the branching fraction of the normalization channel B- -> D**D-0(1,2)-(*())(s). The ratio between the tauonic and muonic semileptonic B decays, with the latter taken from world average values, is also determined and found to be R(D**(0)(1,2)) = 0.13 +/- 0.03(stat) +/- 0.01(syst) +/- 0.02(ext).
Evidence for B- -> D∗∗0 tau- \bar{nu}_{τ} Decays
Bassi G.Membro del Collaboration Group
;Kleijne N.Membro del Collaboration Group
;Morello M. J.Membro del Collaboration Group
;Passaro D.Membro del Collaboration Group
;Pica L.Membro del Collaboration Group
;Riccardi D.Membro del Collaboration Group
;
2025
Abstract
The first evidence for the decay B- -> D**(0)tau(-)(nu) over bar (tau) is obtained using proton-proton collision data collected by the LHCb experiment, corresponding to an integrated luminosity of 9 fb(-1), at centre-of-mass energies of 7, 8, and 13 TeV. Here, the D**0 meson represents any of the three excited charm mesons D-1(2420)(0), D*(2)(2460)(0), and D'(1)(2400)(0). The B- -> D**(0)tau(-)(nu) over bar (tau) signal is measured with a significance of 3.5 sigma, including systematic uncertainties. The combined branching fraction B(B- -> D**(0)(1,2) tau(-)(nu) over bar (tau)) x B(D**(0)(1,2) -> D*(+) pi(-)), where D**(0)(1,2) denotes both D-1(2420)(0) and D*(2)(2460)(0) contributions, is measured to be [0.051 +/- 0.013(stat) +/- 0.006(syst) +/- 0.009(ext)]%, where the last uncertainty reflects that of the branching fraction of the normalization channel B- -> D**D-0(1,2)-(*())(s). The ratio between the tauonic and muonic semileptonic B decays, with the latter taken from world average values, is also determined and found to be R(D**(0)(1,2)) = 0.13 +/- 0.03(stat) +/- 0.01(syst) +/- 0.02(ext).| File | Dimensione | Formato | |
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