RESUMO
The decay B(c)(+) â J/ψπ(+) π(-) π(+) is observed for the first time, using 0.8 fb(-1) of pp collisions at sqrt[s] = 7 TeV collected by the LHCb experiment. The ratio of branching fractions B(B(c)(+) â J/ψπ(+) π(-) π(+))/B(B(c)(+)âJ/ψπ^{+}) is measured to be 2.41 ± 0.30 ± 0.33, where the first uncertainty is statistical and the second is systematic. The result is in agreement with theoretical predictions.
RESUMO
A search is performed for the lepton number violating decay B+ â h- µ+ µ+, where h- represents a K- or a π-, using an integrated luminosity of 36 pb(-1) of data collected with the LHCb detector. The decay is forbidden in the standard model but allowed in models with a Majorana neutrino. No signal is observed in either channel and limits of B(B+ â K- µ+ µ+) < 5.4×10(-8) and B(B+ â π- µ+ µ+) < 5.8×10(-8) are set at the 95% confidence level. These improve the previous best limits by factors of 40 and 30, respectively.
RESUMO
The relative abundance of the three decay modes B(0)âD(-)K(+), B(0)âD(-)π(+), and B(s)(0)âD(s)(-)π(+) produced in 7 TeV pp collisions at the LHC is determined from data corresponding to an integrated luminosity of 35 pb(-1). The branching fraction of B(0)âD(-)K(+) is found to be B(B(0)âD(-)K(+)) = (2.01 ± 0.18(stat) ± 0.14(syst)) × 10(-4). The ratio of fragmentation fractions f(s)/f(d) is determined through the relative abundance of B(s)(0)âD(s)(-)π(+) to B(0)âD(-)K(+) and B(0)âD(-)π(+), leading to f(s)/f(d) = 0.253 ± 0.017 ± 0.017 ± 0.020, where the uncertainties are statistical, systematic, and theoretical, respectively.