A search for the B^0→K^+K^- decay is performed using pp-collision data collected by LHCb. The data set corresponds to integrated luminosities of 1.0 and 2.0 fb^-1 at center-of-mass energies of 7 and 8 TeV, respectively. This decay is observed for the first time, with a significance of more than 5 standard deviations. The analysis also results in an improved measurement of the branching fraction for the B_s^0→π^+π^- decay. The measured branching fractions are B(B^0→K^+K^-)=(7.80±1.27±0.81±0.21)×10^-8 and B(B_s^0→π^+π^-)=(6.91±0.54±0.63±0.19±0.40)×10^-7. The first uncertainty is statistical, the second is systematic, the third is due to the uncertainty on the B^0→K^+π^- branching fraction used as a normalization. For the B_s^0 mode, the fourth accounts for the uncertainty on the ratio of the probabilities for b quarks to hadronize into B_s^0 and B^0 mesons.
Observation of the Annihilation Decay Mode B^0→K^+K^-
Veltri, M;
2017
Abstract
A search for the B^0→K^+K^- decay is performed using pp-collision data collected by LHCb. The data set corresponds to integrated luminosities of 1.0 and 2.0 fb^-1 at center-of-mass energies of 7 and 8 TeV, respectively. This decay is observed for the first time, with a significance of more than 5 standard deviations. The analysis also results in an improved measurement of the branching fraction for the B_s^0→π^+π^- decay. The measured branching fractions are B(B^0→K^+K^-)=(7.80±1.27±0.81±0.21)×10^-8 and B(B_s^0→π^+π^-)=(6.91±0.54±0.63±0.19±0.40)×10^-7. The first uncertainty is statistical, the second is systematic, the third is due to the uncertainty on the B^0→K^+π^- branching fraction used as a normalization. For the B_s^0 mode, the fourth accounts for the uncertainty on the ratio of the probabilities for b quarks to hadronize into B_s^0 and B^0 mesons.I documenti in IRIS sono protetti da copyright e tutti i diritti sono riservati, salvo diversa indicazione.
