The observation of the decay Ξb −→J/ψΛK− is reported, using a data sample corresponding to an integrated luminosity of 3fb−1, collected by the LHCb detector in pp collisions at centre-of-mass energies of 7 and 8TeV. The production rate of Ξb − baryons detected in the decay Ξb −→J/ψΛK− is measured relative to that of Λb 0 baryons using the decay Λb 0→J/ψΛ. Integrated over the b-baryon transverse momentum pT<25GeV/c and rapidity 2.0<y<4.5, the measured ratio is [Formula presented][Formula presented]=(4.19±0.29 (stat)±0.15 (syst))×10−2, where fΞb − and fΛb 0 are the fragmentation fractions of b→Ξb − and b→Λb 0 transitions, and B represents the branching fraction of the corresponding b-baryon decay. The mass difference between Ξb − and Λb 0 baryons is measured to be M(Ξb −)−M(Λb 0)=177.08±0.47 (stat)±0.16 (syst)MeV/c2.
|Number of pages||9|
|Journal||Physics Letters, Section B: Nuclear, Elementary Particle and High-Energy Physics|
|Early online date||26 Jun 2017|
|Publication status||Published - 10 Sep 2017|
ASJC Scopus subject areas
- Nuclear and High Energy Physics