LHCb Collaboration(Aaij, R. et al), Martinez-Vidal, F., Oyanguren, A., Ruiz Valls, P., & Sanchez Mayordomo, C. (2014). Measurement of the CKM angle gamma using B-+/- -> DK +/- with D -> K-S(0)pi(+)pi(-), (KSK+K-)-K-0 decays. J. High Energy Phys., 10(10), 097–52pp.
Abstract: A binned Dalitz plot analysis of B-+/- -> DK +/- decays, with D -> K-S(0) pi(+)pi(-) and D -> K0 S K + K -, is performed to measure the C P -violating observables x(+/-) and y(+/-), which are sensitive to the Cabibbo-Kobayashi-Maskawa angle gamma. The analysis exploits a sample of proton-proton collision data corresponding to 3.0 fb(-1) collected by the LHCb experiment. Measurements from CLEO-c of the variation of the strong-interaction phase of the D decay over the Dalitz plot are used as inputs. The values of the parameters are found to be x(+) = (-7.7 +/- 2.4 +/- 1.0 +/- 0.4) x 10(-2), x(-) = (2.5 +/- 2.5 +/- 1.0 +/- 0.5) x 10(-2), y(+) = (-2.2 +/- 2.5 +/- 0.4 +/- 1.0) x 10-2, and y(-) = (7.5 +/- 2.9 +/- 0.5 +/- 1.4) x 10(-2). The first, second, and third uncertainties are the statistical, the experimental systematic, and that associated with the precision of the strong-phase parameters. These are the most precise measurements of these observables and correspond to +/- = (62(-14)(+15))degrees, with a second solution at gamma -> gamma + 180 degrees, and r(B) = 0.080(-0.021)(+0.019), where r(B) is the ratio between the suppressed and favoured B decay amplitudes.
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LHCb Collaboration(Aaij, R. et al), Martinez-Vidal, F., Oyanguren, A., Ruiz Valls, P., & Sanchez Mayordomo, C. (2014). Measurement of the chi(b) (3 P) mass and of the relative rate of chi(b1) (1 P) and chi(b2) (1 P) production. J. High Energy Phys., 10(10), 088–22pp.
Abstract: The production of chi(b) mesons in proton-proton collisions is studied using a data sample collected by the LHCb detector, at centre-of-mass energies of root s = 7 and 8 TeV and corresponding to an integrated luminosity of 3.0 fb(-1). The chi(b) mesons are identified through their decays to Upsilon(1 S)gamma and Upsilon(2 S)gamma using photons that converted to e(+)e (-) pairs in the detector. The relative prompt production rate of chi(b1)(1 P) and chi(b2)(1 P) mesons is measured as a function of the Upsilon(1 S) transverse momentum in the chi(b) rapidity range 2.0 < y < 4.5. A precise measurement of the chi(b) (3 P) mass is also performed. Assuming a mass splitting between the chi(b1)(3 P) and the chi(b2)(3 P) states of 10.5 MeV/c(2), the measured mass of the chi(b1)(3 P) meson is m (chi(b1)(3 P)) = 10515.7(-3.9)(+2.2)(stat)(-2.1)(+1.5)(syst) MeV/c(2).
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LHCb Collaboration(Aaij, R. et al), Martinez-Vidal, F., Oyanguren, A., Ruiz Valls, P., & Sanchez Mayordomo, C. (2014). First observations of the rare decays B (+) -> K (+)pi (+)pi (-)mu(+)mu (-) and B (+)-> phi K (+)mu(+)mu (-). J. High Energy Phys., 10(10), 064–18pp.
Abstract: First observations of the rare decays B (+) -> K (+)pi (+) pi (-) μ(+) μ(-) and B (+)-> phi K+ mu(+)mu(-) are presented using data corresponding to an integrated luminosity of 3.0 fb(-1), collected by the LHCb experiment at centre-of-mass energies of 7 and 8 TeV. The branching fractions of the decays are B(B (+) -> K (+)pi (+) pi (-) μ(+) μ(-) ) = (4.36 (-0.27) (+0.29) (stat) +/- 0.21 (syst) +/- (norm)) x 10(-7), B(B (+)-> phi K+ mu(+)mu(-)) = (0.82 (+0.19)(-0.17) (stat) (+0.10)(-0.04) (syst) +/- 0.27 (norm)) x 10(-7) where the uncertainties are statistical, systematic, and due to the uncertainty on the branching fractions of the normalisation modes. A measurement of the differential branching fraction in bins of the invariant mass squared of the dimuon system is also presented for the decay B (+) -> K (+)pi (+) pi (-) μ(+) μ(-)
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LHCb Collaboration(Aaij, R. et al), Martinez-Vidal, F., Oyanguren, A., Ruiz Valls, P., & Sanchez Mayordomo, C. (2014). Search for CP violation using T-odd correlations in D-0 -> K+K-pi(+)pi(-) decays. J. High Energy Phys., 10(10), 005–21pp.
Abstract: A search for CP violation using T-odd correlations is performed using the four-body D-0 -> K+K-pi(+)pi(-) decay, selected from semileptonic B decays. The data sample corresponds to integrated luminosities of 1.0 fb(-1) and 2.0 fb(-1) recorded at the centre-of-mass energies of 7 TeV and 8 TeV, respectively. The CP-violating asymmetry alpha(T-odd)(CP) is measured to be (0.18 +/- 0.29 (stat) +/- 0.04 (syst))%. Searches for CP violation in different regions of phase space of the four-body decay, and as a function of the D-0 decay time, are also presented. No significant deviation from the CP conservation hypothesis is found.
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LHCb Collaboration(Aaij, R. et al), Martinez-Vidal, F., Oyanguren, A., Ruiz Valls, P., & Sanchez Mayordomo, C. (2014). Measurement of CP asymmetry in D-0 -> K- K+ and D-0 -> pi(-) pi(+) decays. J. High Energy Phys., 07(7), 041–25pp.
Abstract: Time-integrated CP asymmetries in D-0 decays to the final states K- K+ and pi(-) pi(+) are measured using proton-proton collisions corresponding to 3 fb(-1) of integrated luminosity collected at centre-of-mass energies of 7 TeV and 8 TeV. The D-0 mesons are produced in semileptonic b-hadron decays, where the charge of the accompanying muon is used to determine the initial flavour of the charm meson. The difference in CP asymmetries between the two final states is measured to be Delta A(CP) = A(CP)(K- K+) – A(CP)(pi(-) pi(+)) = (+0.14 +/- 0.16 (stat) +/- 0.08 (syst))% . A measurement of A(CP)(K- K+) is obtained assuming negligible CP violation in charm mixing and in Cabibbo-favoured D decays. It is found to be A(CP)(K- K+) = (-0.06 +/- 0.15 (stat) +/- 0.10 (syst))% , where the correlation coefficient between Delta A(CP) and A(CP)(K- K+) is rho = 0.28. By combining these results, the CP asymmetry in the D-0 -> pi(-) pi(+) channel is A(CP)(pi(-) pi(+)) = (-0.20 +/- 0.19 (stat) +/- 0.10 (syst))%.
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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). Angular analysis of charged and neutral B -> K mu(+) mu(-) decays. J. High Energy Phys., 05(5), 082–25pp.
Abstract: The angular distributions of the rare decays B+ -> K+mu(+)mu(-) and B-0 -> K-S(0)mu(+)mu(-) are studied with data corresponding to 3 fb(-1) of integrated luminosity, collected in proton-proton collisions at 7 and 8 TeV centre-of-mass energies with the LHCb detector. The angular distribution is described by two parameters, F-H and the forward-backward asymmetry of the dimuon system A(FB), which are determined in bins of the dimuon mass squared. The parameter F-H is a measure of the contribution from (pseudo)scalar and tensor amplitudes to the decay width. The measurements of A(FB) and F-H reported here are the most precise to date and are compatible with predictions from the Standard Model.
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LHCb Collaboration(Aaij, R. et al), Oyanguren, A., & Ruiz Valls, P. (2013). Differential branching fraction and angular analysis of the decay B-0 -> K*(0)mu(+)mu(-). J. High Energy Phys., 08(8), 131–31pp.
Abstract: The angular distribution and differential branching fraction of the decay B-0 -> K*(0)mu(+)mu(-) are studied using a data sample, collected by the LHCb experiment in pp collisions at root s = 7 TeV, corresponding to an integrated luminosity of 1.0 fb(-1). Several angular observables are measured in bins of the dimuon invariant mass squared, q(2). A first measurement of the zero-crossing point of the forward-backward asymmetry of the dimuon system is also presented. The zero-crossing point is measured to be q(0)(2) = 4.9 +/- 0.9 GeV2/c(4), where the uncertainty is the sum of statistical and systematic uncertainties. The results are consistent with the Standard Model predictions.
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LHCb Collaboration(Aaij, R. et al), Oyanguren, A., & Ruiz Valls, P. (2013). Differential branching fraction and angular analysis of the decay B-s(0) -> phi mu(+)mu(-). J. High Energy Phys., 07(7), 084–18pp.
Abstract: The determination of the differential branching fraction and the first angular analysis of the decay B-s(0) -> phi mu(+)mu(-) are presented using data, corresponding to an integrated luminosity of 1.0 fb(-1), collected by the LHCb experiment at root s = 7 TeV. The differential branching fraction is determined in bins of q(2), the invariant dimuon mass squared. Integration over the full q2 range yields a total branching fraction of B(B-s(0) -> phi mu(+)mu(-)) = (7.07(-0.59)(+0.64) +/- 0.17 +/- 0.71) x 10(-7), where the first uncertainty is statistical, the second systematic, and the third originates from the branching fraction of the normalisation channel. An angular analysis is performed to determine the angular observables F-L, S-3, A(6), and A(9). The observables are consistent with Standard Model expectations.
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LHCb Collaboration(Aaij, R. et al), Oyanguren, A., & Ruiz Valls, P. (2013). Production of J/psi and Y mesons in pp collisions at root s=8 TeV. J. High Energy Phys., 06(6), 064–31pp.
Abstract: The production of J/psi and gamma mesons in pp collisions at root s = 8 TeV is studied with the LHCb detector. The J/psi and gamma mesons are reconstructed in the mu(+)mu(-) decay mode and the signal yields are determined with a fit to the mu(+)mu(-) invariant mass distributions. The analysis is performed in the rapidity range 2.0 < y < 4.5 and transverse momentum range 0 < PT < 14 (15) GeV/c of the J/psi (gamma) mesons. The J/psi and gamma production cross-sections and the fraction of J/psi mesons from b-hadron decays are measured as a function of the meson P-T and y.
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