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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 B-s(0) -> D-s(-/+) K-/+ decays. J. High Energy Phys., 11(11), 060–30pp.
Abstract: We report on measurements of the time-dependent CP violating observables in B-s(0) -> D-s(-/+) K--/+ decays using a dataset corresponding to 1.0 fb(-1) of pp collisions recorded with the LHCb detector. We find the CP violating observables C-f = 0.53 +/- 0.25 +/- 0.04, A(f)(Delta Gamma) = 0.37 +/- 0.42 +/- 0.20, A((f) over bar)(Delta Gamma) = 0.20 +/- 0.41 +/- 0.20, S-f = -1.09 +/- 0.33 +/- 0.08, S-(f) over bar = -0.36 +/- 0.34 +/- 0.08, where the uncertainties are statistical and systematic, respectively. Using these observables together with a recent measurement of the B-s(0) mixing phase -2 beta(s) leads to the first extraction of the CKM angle gamma from B-s(0) -> D-s(-/+) K--/+ decays, finding gamma = (115(-43)(+28))degrees modulo 180 degrees at 68% CL, where the error contains both statistical and systematic uncertainties.
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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 Lambda(0)(b) -> J / psi p pi(-) decay. J. High Energy Phys., 07(7), 103–19pp.
Abstract: The first observation of the Cabibbo-suppressed decay Lambda(0)(b) -> J / psi p pi(-) is reported using a data sample of proton-proton collisions at 7 and 8TeV, corresponding to an integrated luminosity of 3 fb(-1). A prominent signal is observed and the branching fraction relative to the decay mode Lambda(0)(b) -> J / psi pK(-) is determined to be B(Lambda(0)(b) -> J / psi p pi(-))/ B(Lambda(0)(b) -> J / psi pK(-)) = 0.0824 +/- 0.0025 (stat) +/- 0.0042 (syst). A search for direct CP violation is performed. The difference in the CP asymmetries between these two decays is found to be ACP(Lambda(0)(b) -> J / psi p pi(-))/ A(CP)(Lambda(0)(b) -> J / psi pK(-)) = (+5.7 +/- 2.4 (stat) +/- 1.2 (syst))%, which is compatible with CP symmetry at the 2.2 sigma level.
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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 asymmetries in the decays B-0 -> K-*0 mu(+) mu(-) and B+ -> K+ mu(+) mu(-). J. High Energy Phys., 09(9), 177–18pp.
Abstract: The direct CP asymmetries of the decays B-0 -> K-*0 mu(+) mu(-) and B+ -> K+ mu(+) mu(-) are measured using pp collision data corresponding to an integrated luminosity of 3.0 fb(-1) collected with the LHCb detector. The respective control modes B-0 -> J/psi K+ and B+ -> J/psi K+ are used to account for detection and production asymmetries. The measurements are made in several intervals of mu(+)mu(-) invariant mass squared, with the phi(1020) and charmonium resonance regions excluded. Under the hypothesis of zero CP asymmetry in the control modes, the average values of the asymmetries are A(CP)(B-0 -> K-*0 mu(+) mu(-) and B+ -> K+ mu(+) mu(-)) = -0.035 +/- 0.024 +/- 0.003, A(CP)(B+ -> K+ mu(+) mu(-) = 0.012 +/- 0.017 +/- 0.001, where the first uncertainties are statistical and the second are due to systematic effects. Both measurements are consistent with the Standard Model prediction of small CP asymmetry in these decays.
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LHCb Collaboration(Aaij, R. et al), Martinez-Vidal, F., Oyanguren, A., Ruiz Valls, P., & Sanchez Mayordomo, C. (2015). Measurement of indirect CP asymmetries in D-0 -> K-K+ and D-0 -> pi(-)pi(+) decays using semileptonic B decays. J. High Energy Phys., 04(4), 043–19pp.
Abstract: Time-dependent CP asymmetries in the decay rates of the singly Cabibbo-suppressed decays D-0 -> K-K+ and D-0 -> pi (-) pi(+) are measured in pp collision data corresponding to an integrated luminosity of 3.0 fb(-1) collected by the LHCb experiment. The D-0 mesons are produced in semileptonic b-hadron decays, where the charge of the accompanying muon is used to determine the initial state as D-0 or (D) over bar (0). The asymmetries in effective lifetimes between D-0 and (D) over bar (0) decays, which are sensitive to indirect CP violation, are determined to be A(Gamma) (K-K+) = (-0.134 +/- 0.077(-0.034)(+0.026))%, A(Gamma) (pi(-)pi(+)) = -0.092 +/- 0.145(-0.033)(+0.025))%, where the first uncertainties are statistical and the second systematic. This result is in agreement with previous measurements and with the hypothesis of no indirect CP violation in D (0) decays.
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LHCb Collaboration(Aaij, R. et al), Martinez-Vidal, F., Oyanguren, A., Ruiz Valls, P., & Sanchez Mayordomo, C. (2015). Measurement of the time-dependent CP asymmetries in B-s(0) -> J/psi K-S(0). J. High Energy Phys., 06(6), 131–22pp.
Abstract: The first measurement of decay-time-dependent CP asymmetries in the decay B-S(0) -> J/psi K-S(0) and an updated measurement of the ratio of branching fractions B(B-S(0) -> J/psi K-S(0))/B(B-0 -> J/psi K-S(0)) are presented. The results are obtained using data corresponding to an integrated luminosity of 3.0 fb(-1) of proton-proton collisions recorded with the LHCb detector at centre-of-mass energies of 7 and 8 TeV. The results on the CP asymmetries are A(Delta Gamma)(B-S(0) -> J/psi K-S(0)) = 0.49 +/- (0.77)(0.65)(stat) +/- 0.06(syst), C-dir(B-S(0) -> J/psi K-S(0)) = -0.28 +/- 0.41(stat) +/- 0.08(syst), S-mix(B-S(0) -> J/psi K-S(0)) = -0.08 +/- 0.40(stat) +/- 0.08(syst). The ratio B(B-S(0) -> J/psi K-S(0))/B(B-0 -> J/psi K-S(0)) is measured to be 0.0431 +/- 0.0017(stat) +/- 0.0012(syst) +/- 0.0025(f(s)/f(d)), where the last uncertainty is due to the knowledge of the B-S(0) and B-0 production fractions.
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