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LHCb Collaboration(Aaij, R. et al), Oyanguren, A., & Ruiz Valls, P. (2013). Measurement of the B-0 -> K*(0) e(+) e(-) branching fraction at low dilepton mass. J. High Energy Phys., 05(5), 159–18pp.
Abstract: The branching fraction of the rare decay B-0 -> K*(0) e(+) e(-) in the dilepton mass region from 30 to 1000 MeV/c(2) has been measured by the LHCb experiment, using pp collision data, corresponding to an integrated luminosity of 1.0 fb(-1), at a centre-of-mass energy of 7 TeV. The decay mode B-0 -> J/psi (e(+) e(-)) K*(0) is utilized as a normalization channel. The branching fraction B(B-0 -> K*(0) e(+) e(-)) is measured to be B(B-0 -> K*(0) e(+) e(-))(30-1000 MeV/c2) = (3.1(-0.8)(-0.3)(+0.9)(+0.2) +/- 0.2) x 10(-7) where the fi rst error is statistical, the second is systematic, and the third comes from the uncertainties on the B-0 -> J/K*(0) and J/psi -> e(+) e(-) branching fractions.
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LHCb Collaboration(Aaij, R. et al), Martinez-Vidal, F., Oyanguren, A., & Ruiz Valls, P. (2014). Evidence for the decay B-c(+) -> J/psi 3 pi(+)2 pi(-). J. High Energy Phys., 05(5), 148–17pp.
Abstract: Evidence is presented for the decay B-c(+) -> J/psi 3 pi(+)2 pi(-) using proton-proton collision data, corresponding to an integrated luminosity of 3 fb(-1), collected with the LHCb detector. A signal yield of 32 +/- 8 decays is found with a significance of 4.5 standard deviations. The ratio of the branching fraction of the B-c(+) -> J/psi 3 pi(+)2 pi(-) decay to that of the B-c(+) -> J/psi pi(+) decay is measured to be B(B-c(+) -> J/psi 3 pi(+)2 pi(-))/B(B-c(+) -> J/psi pi(+)) = 1.74 +/- 0.44 +/- 0.24, where the first uncertainty is statistical and the second is systematic.
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LHCb Collaboration(Aaij, R. et al), Martinez-Vidal, F., Oyanguren, A., Ruiz Valls, P., & Sanchez Mayordomo, C. (2014). Differential branching fractions and isospin asymmetries of B -> K ((*)) μ(+) μ(-) decays. J. High Energy Phys., 06(6), 133–22pp.
Abstract: The isospin asymmetries of B -> K μ(+) μ(-) and B -> K (*) μ(+) μ(-) decays and the partial branching fractions of the B (0) -> K (0) μ(+) μ(-), B (+) -> K (+) μ(+) μ(-) and B (+) -> K (*+) μ(+) μ(-) decays are measured as functions of the dimuon mass squared, q (2). The data used correspond to an integrated luminosity of 3 fb(-1) from proton-proton collisions collected with the LHCb detector at centre-of-mass energies of 7 TeV and 8 TeV in 2011 and 2012, respectively. The isospin asymmetries are both consistent with the Standard Model expectations. The three measured branching fractions favour lower values than their respective theoretical predictions, however they are all individually consistent with the Standard Model.
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LHCb Collaboration(Aaij, R. et al), Martinez-Vidal, F., Oyanguren, A., Ruiz Valls, P., & Sanchez Mayordomo, C. (2014). Study of the kinematic dependences of Lambda(0)(b) production in pp collisions and a measurement of the Lambda(0)(b) -> Lambda(+)(c)pi(-) branching fraction. J. High Energy Phys., 08(8), 143–19pp.
Abstract: The kinematic dependences of the relative production rates, f(Lambda b)(0)/f(d), of Lambda(0)(b) baryons and B-0 mesons are measured using Lambda(0)(b) -> Lambda(+)(c)pi(-) and (B) over bar (0) -> D+pi(-) decays. The measurements use proton-proton collision data, corresponding to an integrated luminosity of 1 fb(-1) at a centre-of-mass energy of 7 TeV, recorded in the forward region with the LHCb experiment. The relative production rates are observed to depend on the transverse momentum, pT, and pseudorapidity, eta, of the beauty hadron, in the studied kinematic region 1.5 < pT < 40 GeV/c and 2 < eta < 5. Using a previous LHCb measurement of f(Lambda b)(0)/f(d) in semileptonic decays, the branching fraction B (Lambda(0)(b) -> Lambda(+)(c)pi(-)) = (4.30 +/- 0.03(-0.11)(+0.12)+/- 0.26 +/- 0.21) x 10(-3) is obtained, where the first uncertainty is statistical, the second is systematic, the third is from the previous LHCb measurement of f(Lambda b)(0)/f(d) and the fourth is due to the (B) over bar (0) -> D+pi(-) branching fraction. This is the most precise measurement of a Lambda(0)(b) branching fraction to date.
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LHCb Collaboration(Aaij, R. et al), Martinez-Vidal, F., Oyanguren, A., Ruiz Valls, P., & Sanchez Mayordomo, C. (2014). Observation of the B-s(0) -> J/psi (KsK +/-)-K-0 pi(-/+) decay. J. High Energy Phys., 07(7), 140–29pp.
Abstract: Decays of the form B-s(0) -> J/psi K(s)(0)h(+)h((1)-) (h((1)) = K, pi) are searched for in proton-proton collision data corresponding to an integrated luminosity of 1.0 fb(-1) recorded with the LHCb detector. The first observation of the B-s(0) -> J/psi (KsK +/-)-K-0 pi(-/+) decay is reported, with significance in excess of 10 standard deviations. The B-0 -> J/psi (KsK+K-)-K-0 decay is also observed for the first time. The branching fraction of B-s(0) -> J/psi K(s)(0)h(+)h((1)-) is determined, to significantly better precision than previous measurements, using B-0 -> J/psi K(s)(0)h(+)h((1)-) as a normalisation channel. Branching fractions and upper limits of the other B-(s)(0) -> J/psi K-s(0)pi(+)pi(-) (s modes are determined relative to that of the B-0 -> J/psi K-s(0)pi(+)pi(-) decay.
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