The first observation of the semileptonic b-baryon decay Λb0→Λc+τ-ν¯τ, with a significance of 6.1σ, is reported using a data sample corresponding to 3 fb-1 of integrated luminosity, collected by the LHCb experiment at center-of-mass energies of 7 and 8 TeV at the LHC. The τ- lepton is reconstructed in the hadronic decay to three charged pions. The ratio K=B(Λb0→Λc+τ-ν¯τ)/B(Λb0→Λc+π-π+π-) is measured to be 2.46±0.27±0.40, where the first uncertainty is statistical and the second systematic. The branching fraction B(Λb0→Λc+τ-ν¯τ)=(1.50±0.16±0.25±0.23)% is obtained, where the third uncertainty is from the external branching fraction of the normalization channel Λb0→Λc+π-π+π-. The ratio of semileptonic branching fractions R(Λc+)B(Λb0→Λc+τ-ν¯τ)/B(Λb0→Λc+μ-ν¯μ) is derived to be 0.242±0.026±0.040±0.059, where the external branching fraction uncertainty from the channel Λb0→Λc+μ-ν¯μ contributes to the last term. This result is in agreement with the standard model prediction.

Aaij, R., Abdelmotteleb, A., Beteta, C., Abudinen, F., Ackernley, T., Adeva, B., et al. (2022). Observation of the Decay Λb0 → Λc+ τ- ν ¯ τ. PHYSICAL REVIEW LETTERS, 128(19) [10.1103/PhysRevLett.128.191803].

Observation of the Decay Λb0 → Λc+ τ- ν ¯ τ

Borsato M.;Calvi M.;Capelli S.;Carniti P.;Fazzini D.;Garcia Pardinas J.;Gotti C.;Martinazzoli L.;Martinelli M.;Meloni S.;Minotti A.;Petruzzo M.;Pizzichemi M.;Salomoni M.;Shields E. B.;
2022

Abstract

The first observation of the semileptonic b-baryon decay Λb0→Λc+τ-ν¯τ, with a significance of 6.1σ, is reported using a data sample corresponding to 3 fb-1 of integrated luminosity, collected by the LHCb experiment at center-of-mass energies of 7 and 8 TeV at the LHC. The τ- lepton is reconstructed in the hadronic decay to three charged pions. The ratio K=B(Λb0→Λc+τ-ν¯τ)/B(Λb0→Λc+π-π+π-) is measured to be 2.46±0.27±0.40, where the first uncertainty is statistical and the second systematic. The branching fraction B(Λb0→Λc+τ-ν¯τ)=(1.50±0.16±0.25±0.23)% is obtained, where the third uncertainty is from the external branching fraction of the normalization channel Λb0→Λc+π-π+π-. The ratio of semileptonic branching fractions R(Λc+)B(Λb0→Λc+τ-ν¯τ)/B(Λb0→Λc+μ-ν¯μ) is derived to be 0.242±0.026±0.040±0.059, where the external branching fraction uncertainty from the channel Λb0→Λc+μ-ν¯μ contributes to the last term. This result is in agreement with the standard model prediction.
Articolo in rivista - Articolo scientifico
Leptonic, semileptonic & radiative decays; Bottom baryons; Hadron colliders; Flavor Symmetries
English
2022
128
19
191803
none
Aaij, R., Abdelmotteleb, A., Beteta, C., Abudinen, F., Ackernley, T., Adeva, B., et al. (2022). Observation of the Decay Λb0 → Λc+ τ- ν ¯ τ. PHYSICAL REVIEW LETTERS, 128(19) [10.1103/PhysRevLett.128.191803].
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Utilizza questo identificativo per citare o creare un link a questo documento: https://hdl.handle.net/10281/401369
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