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), Garcia Martin, L. M., Henry, L., Jashal, B. K., Martinez-Vidal, F., Oyanguren, A., et al. (2020). Measurement of CP violation in B-0 -> (DD -/+)-D-*+/- decays. J. High Energy Phys., 03(3), 147–28pp.
Abstract: The decay-time-dependent CP asymmetry in B-0 -> (DD -/+)-D-*+/- decays is mea- sured using a data set corresponding to an integrated luminosity of 9 fb(-1) recorded by the LHCb detector in proton-proton collisions at centre-of-mass energies of 7, 8 and 13 TeV. The CP parameters are measured asSD*D=-0.861 +/- 0.077 +/- 0.019,Delta SD*D=0.019 +/- 0.075 +/- 0.012,CD*D=-0.059 +/- 0.092 +/- 0.020,Delta CD*D=-0.031 +/- 0.092 +/- 0.016,AD*D=0.008 +/- 0.014 +/- 0.006. The analysis provides the most precise single measurement of CP violation in this decay channel to date. All parameters are consistent with their current world average values.
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LHCb Collaboration(Aaij, R. et al), Garcia Martin, L. M., Martinez-Vidal, F., Oyanguren, A., Remon Alepuz, C., Ruiz Valls, P., et al. (2017). Observation of the decay Lambda(0)(b) -> pK(-)mu(+)mu(-) and a search for CP violation. J. High Energy Phys., 06(6), 108–17pp.
Abstract: A search for CP violation in the decay Lambda(0)(b) -> pK(-)mu(+)mu(-) is presented. This decay is mediated by flavour-changing neutral-current transitions in the Standard Model and is potentially sensitive to new sources of CP violation. The study is based on a data sample of proton-proton collisions recorded with the LHCb experiment, corresponding to an integrated luminosity of 3 fb(-1). The Lambda(0)(b) -> pK(-)mu(+)mu(-) decay is observed for the first time, and two observables that are sensitive to different manifestations of CP violation are measured, Delta A(CP) equivalent to A(CP) (Lambda(0)(b) -> pK(-)mu(+)mu(-)) – A(CP) (Lambda(0)(b) -> pK(-)J/psi) and a(CP)((T) over cap -odd), where the latter is based on asymmetries in the angle between the mu(+)mu(-) and pK(-) decay planes. These are measured to be Delta A(CP) = (-3.5 +/- 5.0 (stat) +/- 0.2 (syst)) x 10(-2), a(CP)((T) over cap -odd) = (1.2 +/- 5.0 (stat) +/- 0.7 (syst)) x 10(-2), and no evidence for CP violation is found.
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ATLAS Collaboration(Aad, G. et al), Alvarez Piqueras, D., Cabrera Urban, S., Castillo Gimenez, V., Costa, M. J., Fernandez Martinez, P., et al. (2016). Measurement of the CP-violating phase phi(s) and the B-s(0) meson decay width difference with B-s(0) -> J/psi phi decays in ATLAS. J. High Energy Phys., 08(8), 147–45pp.
Abstract: A measurement of the B-s(0) decay parameters in the B-s(0) -> J/psi/phi channel using an integrated luminosity of 14.3 fb(-1) collected by the ATLAS detector from 8TeV pp collisions at the LHC is presented. The measured parameters include the CP-violating phase phi(s), the decay width Gamma(s) and the width di ff erence between the mass eigenstates Delta Gamma(s). The values measured for the physical parameters are statistically combined with those from 4.9 fb-1 of 7TeV data, leading to the following: phi(s) = -0.090 +/- 0.078 (stat.) +/- 0.041 (syst.) rad Delta Gamma s = 0.085 +/- 0.011 (stat.) +/- 0.007 (syst.) ps(-1) Gamma(s) = 0.675 +/- 0.003 (stat.) +/- 0.003 (syst:) ps(-1). In the analysis the parameter Delta Gamma(s) is constrained to be positive. Results for phi(s) and Delta Gamma(s) are also presented as 68% and 95% likelihood contours in the phi(s)-Delta Gamma(s) plane. Also measured in this decay channel are the transversity amplitudes and corresponding strong phases. All measurements are in agreement with the Standard Model predictions.
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LHCb Collaboration(Aaij, R. et al), Garcia Martin, L. M., Henry, L., Martinez-Vidal, F., Oyanguren, A., Remon Alepuz, C., et al. (2018). Measurement of the CP asymmetry in B- -> (Ds-D0) and B- -> (D-D0) decays. J. High Energy Phys., 05(5), 160–17pp.
Abstract: The CP asymmetry in B- -> (Ds-D0) and B- -> (D-D0) decays is measured using LHCb data corresponding to an integrated luminosity of 3.0 fb(-1), collected in pp collisions at centre-of-mass energies of 7 and 8TeV. The results are A(CP) (B- -> (Ds-D0)) = (-0.4 +/- 0.5 +/- 0.5)% and A(CP) (B- -> (D-D0)) = (2.3 +/- 2.7 +/- 0.4)%, where the first uncertainties are statistical and the second systematic. This is the first measurement of A(CP) (B- -> (Ds-D0)) and the most precise determination of A(CP) (B- -> (D-D0)). Neither result shows evidence of CP violation.
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