First observation of B0->J/\psi K+K- and search for B0->J/\psi\phi\ decays

Abstract : The first observation of the B0->J/\psi K+K- decay is presented with a data sample corresponding to an integrated luminosity of 1.0/fb 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(B0->J/\psi K+K-) = (2.53 +/- 0.31 +/- 0.19)x10^{-6}, where the first uncertainty is statistical and the second is systematic. An amplitude analysis of the final state in the B0->J/\psi K+K- decay is performed to separate resonant and nonresonant contributions in the K+K- spectrum. Evidence of the a0(980) resonance is reported with statistical significance of 3.9 standard deviations. The corresponding product branching fraction is measured to be B(B0->J/\psi a0(980), a0(980)->K+K-)=(4.70 +/- 3.31 +/- 0.72)x10^{-7}, yielding an upper limit of B(B0->J/\psi a0(980), a0(980)->K+K-)<9.0x10^{-7} at 90% confidence level. No evidence of the resonant decay B0->J/\psi\phi\; is found, and an upper limit on its branching fraction is set to be B(B0->J/\psi\phi)< 1.9x10^{-7} at 90% confidence level.
Document type :
Journal articles

http://hal.in2p3.fr/in2p3-00854737
Contributor : Danielle Cristofol <>
Submitted on : Wednesday, August 28, 2013 - 8:31:07 AM
Last modification on : Wednesday, September 16, 2020 - 4:23:36 PM

Citation

R. Aaij, B. Adeva, M. Adinolfi, C. Adrover, A. Affolder, et al.. First observation of B0->J/\psi K+K- and search for B0->J/\psi\phi\ decays. Physical Review D, American Physical Society, 2013, 88, pp.072005. ⟨10.1103/PhysRevD.88.072005⟩. ⟨in2p3-00854737⟩

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