2017/01/31 by LHCb collaboration, R. Aaij, B. Adeva +764 · 1 citation
Physics and Astronomy · #hep-ex
paper · pdf · doi:10.1016/j.physletb.2017.06.045
published as Phys. Lett. B 772 (2017) 265-273 · All figures and tables, along with any supplementary material and additional information, are available at https://lhcbproject.web.cern.ch/lhcbproject/Publications/LHCbProjectPublic/LHCb-PAPER-2016-053.html
arxiv created 2017/07/12 · arxiv updated 2017/07/13
The observation of the decay \varXi-b→ J/ψ\varLambda K- is reported, using a data sample corresponding to an integrated luminosity of 3~fb-1, collected by the LHCb detector in pp collisions at centre-of-mass energies of 7 and 8~TeV. The production rate of \varXib- baryons detected in the decay \varXib-→ J/ψ\varLambda K- is measured relative to that of \varLambdab0 baryons using the decay \varLambdab0→ J/ψ\varLambda. Integrated over the b-baryon transverse momentum p\rm T<25~GeV/c and rapidity 2.0<y<4.5, the measured ratio is \fracf_\varXib-f_\varLambdab0\fracB(\varXib-→ J/ψ\varLambda K-)B(\varLambdab0→ J/ψ\varLambda)=(4.19± 0.29~(stat)±0.15~(syst))× 10-2,where f_\varXib- and f_\varLambdab0 are the fragmentation fractions of b→\varXib- and b→\varLambdab0 transitions, and B represents the branching fraction of the corresponding b-baryon decay. The mass difference between \varXib- and \varLambdab0 baryons is measured to be M(\varXib-)-M(\varLambdab0)=177.08±0.47~(stat)±0.16~(syst )~MeV/c2.