Using a pp collision data sample corresponding to an integrated luminosity of 3.0fb^-1, collected by the LHCb detector, we present the first search for the strangeness-changing weak decay Xi_b^-Lambda_b^0pi^-. No b hadron decay of this type has been seen before. A signal for this decay, corresponding to a significance of 3.2 standard deviations, is reported. The relative rate is measured to be f_Xi_b^-/f_Lambda_b^0B(Xi_b^-Lambda_b^0pi^-)=(5.7± 1.8_-0.9^+0.8)*10^-4,where f_Xi_b^- and f_Lambda_b^0 are the bXi_b^- and bLambda_b^0 fragmentation fractions, and B(Xi_b^-Lambda_b^0pi^-) is the branching fraction. Assuming f_Xi_b^-/f_Lambda_b^0 is bounded between 0.1 and 0.3, the branching fraction B(Xi_b^-Lambda_b^0pi^-) would lie in the range from (0.57±0.21)% to (0.19±0.07)%.
Evidence for the Strangeness-Changing Weak Decay Xi_b^-Lambda_b^0pi^-
AURIEMMA, Giulio;SATRIANO, Celestina;
2015-01-01
Abstract
Using a pp collision data sample corresponding to an integrated luminosity of 3.0fb^-1, collected by the LHCb detector, we present the first search for the strangeness-changing weak decay Xi_b^-Lambda_b^0pi^-. No b hadron decay of this type has been seen before. A signal for this decay, corresponding to a significance of 3.2 standard deviations, is reported. The relative rate is measured to be f_Xi_b^-/f_Lambda_b^0B(Xi_b^-Lambda_b^0pi^-)=(5.7± 1.8_-0.9^+0.8)*10^-4,where f_Xi_b^- and f_Lambda_b^0 are the bXi_b^- and bLambda_b^0 fragmentation fractions, and B(Xi_b^-Lambda_b^0pi^-) is the branching fraction. Assuming f_Xi_b^-/f_Lambda_b^0 is bounded between 0.1 and 0.3, the branching fraction B(Xi_b^-Lambda_b^0pi^-) would lie in the range from (0.57±0.21)% to (0.19±0.07)%.I documenti in IRIS sono protetti da copyright e tutti i diritti sono riservati, salvo diversa indicazione.
