The first observation of the B ̄0→J/ψK +K - decay is presented with a data sample corresponding to an integrated luminosity of 1.0 fb -1 of pp collisions at a center-of-mass energy of 7 TeV collected with the LHCb detector. The branching fraction is measured to be B(B ̄0→J/ψK +K -)=(2.53±0.31±0.19)×10 -6, where the first uncertainty is statistical and the second is systematic. An amplitude analysis of the final state in the B ̄0→J/ψK +K - decay is performed to separate resonant and nonresonant contributions in the K +K - spectrum. Evidence of the a 0(980) resonance is reported with statistical significance of 3.9 standard deviations. The corresponding product branching fraction is measured to be B(B ̄0→J/ψa 0(980),a 0(980)→K +K -)=(4.70±3.31±0. 72)×10 -7, yielding an upper limit of B(B ̄0→J/ψa 0(980),a 0(980)→K +K -)<9.0×10 -7 at 90% confidence level. No evidence of the resonant decay B ̄0→J/ψφ is found, and an upper limit on its branching fraction is set to be B(B ̄0→J/ψφ)<1.9×10 -7 at 90% confidence level.
|Journal||Physical Review D - Particles, Fields, Gravitation and Cosmology|
|Publication status||Published - 14 Oct 2013|
Copyright 2013 Elsevier B.V., All rights reserved.
All Science Journal Classification (ASJC) codes
- Nuclear and High Energy Physics
- Physics and Astronomy (miscellaneous)