Using a data sample of e+e- collisions corresponding to an integrated luminosity of 567 pb-1 collected at a center-of-mass energy of s=4.6 GeV with the BESIII detector, we measure the absolute branching fraction of the inclusive semileptonic Λc+ decay with a double-tag method. We obtain B(Λc+→Xe+νe)=(3.95±0.34±0.09)%, where the first uncertainty is statistical and the second systematic. Using the known Λc+ lifetime and the charge-averaged semileptonic decay width of nonstrange charmed mesons (D0 and D+), we obtain the ratio of the inclusive semileptonic decay widths Γ(Λc+→Xe+νe)/Γ(D→Xe+νe)=1.26±0.12.
Bibliographical noteFunding 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 the National Key Basic Research Program of China under Contract No. 2015CB856700; the National Natural Science Foundation of China (NSFC) under Contracts No. 11235011, No. 11335008, No. 11425524, No. 11625523, and No. 11635010; the Chinese Academy of Sciences (CAS) Large-Scale Scientific Facility Program; the CAS Center for Excellence in Particle Physics (CCEPP); Joint Large-Scale Scientific Facility Funds of the NSFC and CAS under Contracts No. U1332201, No. U1532257, and No. U1532258; CAS under Contracts No. KJCX2-YW-N29 and No. KJCX2-YW-N45; CAS Key Research Program of Frontier Sciences under Contracts No. QYZDJ-SSW-SLH003 and No. QYZDJ-SSW-SLH040; 100 Talents Program of CAS; National 1000 Talents Program of China; INPAC and Shanghai Key Laboratory for Particle Physics and Cosmology; German Research Foundation DFG under Contracts No. Collaborative Research Center CRC 1044 and No. FOR 2359; Istituto Nazionale di Fisica Nucleare, Italy; Koninklijke Nederlandse Akademie van Wetenschappen (KNAW) under Contract No. 530-4CDP03; Ministry of Development of Turkey under Contract No. DPT2006K-120470; National Science and Technology fund; The Swedish Research Council; U.S. Department of Energy under Contracts No. DE-FG02-05ER41374, No. DE-SC-0010118, No. DE-SC-0010504 and No. DE-SC-0012069; University of Groningen (RuG) and the Helmholtzzentrum fuer Schwerionenforschung GmbH (GSI), Darmstadt; WCU Program of National Research Foundation of Korea under Contract No. R32-2008-000-10155-0.