Precision measurement of the mass and lifetime of the Xi(b)(0) baryon

Using a proton-proton collision data sample corresponding to an integrated luminosity of 3 fb(-1) collected by LHCb at center-of-mass energies of 7 and 8 TeV, about 3800 Xi(b)(0) Xi(c)(+)pi(-), Xi(c)(+)) pK(-)pi(+) signal decays are reconstructed. From this sample, the first measurement of the Xi(b)(0) baryon lifetime is made, relative to that of the Lambda(b)(0) baryon. The mass differences M(Xi(b)(0))-M(Lambda(b)(0)) and M(Xi(c)(+))-M(Lambda(c)(+)) are also measured with precision more than 4 times better than the current world averages. The resulting values are tau(Xi(b)(0))/tau(Lambda)(b)(0)) = 1.006 ± 0.018 ± 0.010,M(Xi(b)(0))-M(Lambda(b)(0)) = 172.44 ± 0.39 ± 0.17 MeV/c(2),M(Xi(c)(+))-M(Lambda(c)(+)) = 181.51 ± 0.14 ± 0.10 MeV/c(2),where the first uncertainty is statistical and the second is systematic. The relative rate of Xi(b)(0) to Lambda(b)(0) baryon production is measured to be f(Xi)(b)(0))/f(Lambda)(b)(0))B(Xi(b)(0) Xi(c)(+)pi(-))/B(Lambda(b)(0) Lambda(c)(+)pi(-))B(Xi(c)(+) pK(-)pi(+))/B(Lambda(c)(+) pK(-)pi(+)) = (1.88 ± 0.04 ± 0.03) * 10(-2),where the first factor is the ratio of fragmentation fractions, b Xi(b)(0) relative to b Lambda(b)(0). Relative production rates as functions of transverse momentum and pseudorapidity are also presented.