Using a pp collision data sample corresponding to an integrated luminosity of 3.0 fb^-1, collected by the LHCb detector, we present the first search for the strangeness-changing weak decay Ξ_b^-→Λ_b^0π^-. 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_Ξ_b^-/f_Λ_b^0B(Ξ_b^-→Λ_b^0π^-)=(5.7±1.8_-0.9^+0.8)×10^-4,where f_Ξ_b^- and f_Λ_b^0 are the b→Ξ_b^- and b→Λ_b^0 fragmentation fractions, and B(Ξ_b^-→Λ_b^0π^-) is the branching fraction. Assuming f_Ξ_b^-/f_Λ_b^0 is bounded between 0.1 and 0.3, the branching fraction B(Ξ_b^-→Λ_b^0π^-) would lie in the range from (0.57±0.21)% to (0.19±0.07)%.
Evidence for the Strangeness-Changing Weak Decay Ξ_b^-→Λ_b^0π^-
VELTRI, MICHELE;
2015
Abstract
Using a pp collision data sample corresponding to an integrated luminosity of 3.0 fb^-1, collected by the LHCb detector, we present the first search for the strangeness-changing weak decay Ξ_b^-→Λ_b^0π^-. 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_Ξ_b^-/f_Λ_b^0B(Ξ_b^-→Λ_b^0π^-)=(5.7±1.8_-0.9^+0.8)×10^-4,where f_Ξ_b^- and f_Λ_b^0 are the b→Ξ_b^- and b→Λ_b^0 fragmentation fractions, and B(Ξ_b^-→Λ_b^0π^-) is the branching fraction. Assuming f_Ξ_b^-/f_Λ_b^0 is bounded between 0.1 and 0.3, the branching fraction B(Ξ_b^-→Λ_b^0π^-) 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.
