TY - JOUR
T1 - First observation of the semileptonic decay Λc+ →pK-e+νe
AU - BESIII Collaboration
AU - Ablikim, M.
AU - Achasov, M. N.
AU - Kalantar-Nayestanaki, N.
AU - Kappert, R.
AU - Kavatsyuk, M.
AU - Messchendorp, J.
AU - Rodin, V.
N1 - Funding Information:
The BESIII Collaboration thanks the staff of BEPCII and the IHEP computing center for their strong support. This work is supported in part by National Key R&D Program of China under Contracts No. 2020YFA0406400, and No. 2020YFA0406300; National Natural Science Foundation of China (NSFC) under Contracts No. 11635010, No. 11735014, No. 11835012, No. 11935015, No. 11935016, No. 11935018, No. 11961141012, No. 12022510, No. 12025502, No. 12035009, No. 12035013, No. 12192260, No. 12192261, No. 12192262, No. 12192263, No. 12192264, and No. 12192265; the Chinese Academy of Sciences (CAS) Large-Scale Scientific Facility Program; Joint Large-Scale Scientific Facility Funds of the NSFC and CAS under Contract No. U1832207; CAS Key Research Program of Frontier Sciences under Contract No. QYZDJ-SSW-SLH040; 100 Talents Program of CAS; INPAC and Shanghai Key Laboratory for Particle Physics and Cosmology; ERC under Contract No. 758462; European Union’s Horizon 2020 research and innovation programme under Marie Sklodowska-Curie grant agreement under Contract No. 894790; German Research Foundation DFG under Contracts Nos. 443159800, Collaborative Research Center CRC 1044, GRK 2149; Istituto Nazionale di Fisica Nucleare, Italy; Ministry of Development of Turkey under Contract No. DPT2006K-120470; National Science and Technology fund; STFC (United Kingdom); The Royal Society, UK under Contracts No. DH140054 and No. DH160214; The Swedish Research Council; U.S. Department of Energy under Contract No. DE-FG02-05ER41374.
Publisher Copyright:
© 2022 authors. Published by the American Physical Society.
PY - 2022/12/1
Y1 - 2022/12/1
N2 - 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.
AB - 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.
UR - http://www.scopus.com/inward/record.url?scp=85146448936&partnerID=8YFLogxK
U2 - 10.1103/PhysRevD.106.112010
DO - 10.1103/PhysRevD.106.112010
M3 - Article
SN - 2470-0010
VL - 106
JO - Physical Review D
JF - Physical Review D
IS - 11
M1 - 112010
ER -