Using 4.5 fb-1 of e+e- annihilation data samples collected at the center-of-mass energies ranging from 4.600 GeV to 4.699 GeV with the BESIII detector at the BEPCII collider, a first study of the semileptonic decays Λc+→pK-e+νe, Λc+→Λ(1520)e+νe and Λc+→Λ(1405)e+νe is performed. The Λc+→pK-e+νe decay is observed with a significance of 8.2σ and the branching fraction is measured to be B(Λc+→pK-e+νe)=(0.88±0.17stat±0.07syst)×10-3. We also report evidence of Λc+→Λ(1520)e+νe and Λc+→Λ(1405)e+νe with significances of 3.3σ and 3.2σ, respectively, and measure B(Λc+→Λ(1520)e+νe)=(1.02±0.52stat±0.11syst)×10-3 and B(Λc+→Λ(1405)[→pK-]e+νe)=(0.42±0.19stat±0.04syst)×10-3. Combining these with the inclusive semileptonic Λc+ branching fraction measured by BESIII, the relative fraction is determined to be [B(Λc+→pK-e+νe)/B(Λc+→Xe+νe)]=(2.1±0.4stat±0.2syst)%, which provides a clear confirmation that semileptonic Λc+ decays are not saturated by the Λℓ+νℓ final state
First observation of the semileptonic decay Λc+ →pK-e+νe
I. Garzia;
2022
Abstract
Using 4.5 fb-1 of e+e- annihilation data samples collected at the center-of-mass energies ranging from 4.600 GeV to 4.699 GeV with the BESIII detector at the BEPCII collider, a first study of the semileptonic decays Λc+→pK-e+νe, Λc+→Λ(1520)e+νe and Λc+→Λ(1405)e+νe is performed. The Λc+→pK-e+νe decay is observed with a significance of 8.2σ and the branching fraction is measured to be B(Λc+→pK-e+νe)=(0.88±0.17stat±0.07syst)×10-3. We also report evidence of Λc+→Λ(1520)e+νe and Λc+→Λ(1405)e+νe with significances of 3.3σ and 3.2σ, respectively, and measure B(Λc+→Λ(1520)e+νe)=(1.02±0.52stat±0.11syst)×10-3 and B(Λc+→Λ(1405)[→pK-]e+νe)=(0.42±0.19stat±0.04syst)×10-3. Combining these with the inclusive semileptonic Λc+ branching fraction measured by BESIII, the relative fraction is determined to be [B(Λc+→pK-e+νe)/B(Λc+→Xe+νe)]=(2.1±0.4stat±0.2syst)%, which provides a clear confirmation that semileptonic Λc+ decays are not saturated by the Λℓ+νℓ final stateFile | Dimensione | Formato | |
---|---|---|---|
PhysRevD.106.112010.pdf
accesso aperto
Descrizione: Full text editoriale
Tipologia:
Full text (versione editoriale)
Licenza:
Creative commons
Dimensione
1.31 MB
Formato
Adobe PDF
|
1.31 MB | Adobe PDF | Visualizza/Apri |
I documenti in SFERA sono protetti da copyright e tutti i diritti sono riservati, salvo diversa indicazione.