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 a0(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/ψa0(980),a0(980)→K+K-)=(4.70±3.31±0.72)×10-7, yielding an upper limit of B(B¯0→J/ψa0(980),a0(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.

First observation of B[over ¯]^{0}→J/ψK^{+}K^{-} and search for B[over ¯]^{0}→J/ψϕ decays

BALDINI, Wander;BOZZI, Concezio;SAVRIE', Mauro;
2013

Abstract

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 a0(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/ψa0(980),a0(980)→K+K-)=(4.70±3.31±0.72)×10-7, yielding an upper limit of B(B¯0→J/ψa0(980),a0(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.
2013
R., Aaij; B., Adeva; M., Adinolfi; C., Adrover; A., Affolder; Z., Ajaltouni; J., Albrecht; F., Alessio; M., Alexander; S., Ali; G., Alkhazov; P., Alva...espandi
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Utilizza questo identificativo per citare o creare un link a questo documento: https://hdl.handle.net/11392/2088612
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