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LHCb Collaboration(Aaij, R. et al), Jaimes Elles, S. J., Jashal, B. K., Martinez-Vidal, F., Oyanguren, A., Rebollo De Miguel, M., et al. (2024). Measurement of the CKM angle γ in the B0 → D K*0 channel using self-conjugate D → KS0 h+ h- decays. Eur. Phys. J. C, 84(2), 206–18pp.
Abstract: A model-independent study of CP violation in B-0 -> DK (*0) decays is presented using data corresponding to an integrated luminosity of 9 fb(-1) collected by the LHCb experiment at centre-of-mass energies of v s = 7, 8 and 13TeV. The CKM angle. is determined by examining the distributions of signal decays in phase-space bins of the self-conjugate D. K(S)(0)h(+) h(-) decays, where h = p, K. Observables related to CP violation are measured and the angle. is determined to be = (49+22 -19). Measurements of the amplitude ratio and strong-phase difference between the favoured and suppressed B-0 decays are also presented.
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LHCb Collaboration(Aaij, R. et al), Jaimes Elles, S. J., Jashal, B. K., Martinez-Vidal, F., Oyanguren, A., Rebollo De Miguel, M., et al. (2023). Measurement of the CKM angle γ using the B± → D*h± channels. J. High Energy Phys., 12(12), 013–32pp.
Abstract: A measurement of the CP-violating observables from B -> (DK +/-)-K-* and B-+/- -> D-*pi(+/-) decays is presented, where D-*(D) is an admixture of D-*0 and D-0 (D-0 and (0)) states and is reconstructed through the decay chains D-*-> D pi(0)/gamma and D -> KS0 pi+pi-/KS0K+K-. The measurement is performed by analysing the signal yield variation across the D decay phase space and is independent of any amplitude model. The data sample used was collected by the LHCb experiment in proton-proton collisions and corresponds to a total integrated luminosity of 9 fb(-1) at centre-of-mass energies of 7, 8 and 13 TeV. The CKM angle gamma is determined to be (69(-14)(+13))degrees using the measured CP-violating observables. The hadronic parameters r(B)(D)*(K +/-),r(B)(D)*(pi +/-),delta(D)(B)*(K +/-),delta(D)(B)*(pi +/-), which are the ratios and strong phase differences between favoured and suppressed B-+/- decays, are also reported.
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LHCb Collaboration(Aaij, R. et al), Jaimes Elles, S. J., Jashal, B. K., Martinez-Vidal, F., Oyanguren, A., Rebollo De Miguel, M., et al. (2023). Measurement of the CKM angle γ with B± → D[K∓π±π±π∓] h± decays using a binned phase-space approach. J. High Energy Phys., 07(7), 138–31pp.
Abstract: The CKM angle gamma is determined from CP-violating observables measured in B-+/- -> D[K--/+pi(+/-)pi(+/-)pi(-/+)]h(+/-), (h = K, pi) decays, where the measurements are performed in bins of the decay phase-space of the D meson. Using proton-proton collision data collected by the LHCb experiment at centre-of-mass energies of 7, 8 and 13TeV, corresponding to a total integrated luminosity of 9 fb(-1), gamma is determined to be gamma = (54.8 (+6.0)(-5.8) (+0.6)(-0.6) (+6.7)(-4.3))degrees, where the first uncertainty is statistical, the second systematic and the third from the external inputs on the coherence factors and strong phases of the D-meson decays.
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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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LHCb Collaboration(Aaij, R. et al), Martinez-Vidal, F., Oyanguren, A., Remon Alepuz, C., Ruiz Valls, P., & Sanchez Mayordomo, C. (2016). Measurement of the CP Asymmetry in B-s(0) – (B)over-bar(s)(0) Mixing. Phys. Rev. Lett., 117(6), 061803–9pp.
Abstract: The CP asymmetry in the mixing of B-s(0) and (B) over bar (0)(s) mesons is measured in proton-proton collision data corresponding to an integrated luminosity of 3.0 fb(-1), recorded by the LHCb experiment at center-of-mass energies of 7 and 8 TeV. Semileptonic B-s(0) and (B) over bar (s) (0) decays are studied in the inclusive mode D-s(-/+)mu(+/-)nu((-)) X-mu with the D-s(-/+) mesons reconstructed in the K+K-pi(-/+) final state. Correcting the observed charge asymmetry for detection and background effects, the CP asymmetry is found to be a(sl)(s) = (0.39 +/- 0.26 +/- 0.20)%, where the first uncertainty is statistical and the second systematic. This is the most precise measurement of a(sl)(s) to date. It is consistent with the prediction from the standard model and will constrain new models of particle physics.
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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). Measurement of the CP Violation Parameter A(r) in D-0 -> K+K- and D-0 -> pi(+)pi(-) Decays. Phys. Rev. Lett., 118(26), 261803–9pp.
Abstract: Asymmetries in the time-dependent rates of D-0 -> K+K- and D-0 -> pi(+)pi(-)decays are measured in a pp collision data sample collected with the LHCb detector during LHC Run 1, corresponding to an integrated luminosity of 3 fb(-1). The asymmetries in effective decay widths between D-0 and (D) over bar (0) decays, sensitive to indirect CP violation, are measured to be A(r)(K+K-) = (-0.30 +/- 0.32 0.10) x 10(-3) and A(r) pi(+)pi(-)) = (0.46 +/- 0.58 +/- 0.12) x 10(-3), where the first uncertainty is statistical and the second systematic. These measurements show no evidence for CP violation and improve on the precision of the previous best measurements by nearly a factor of two.
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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 CP-violating phase beta in B-0 -> J/psi pi(+)pi(-) decays and limits on penguin effects. Phys. Lett. B, 742, 38–49.
Abstract: Time-dependent CP violation is measured in the (B-0) over bar -> J/psi pi(+)pi(-) p-channel for each pi(+)pi(-) resonant final state using data collected with an integrated luminosity of 3.0 fb(-1) in pp collisions using the LHCb detector. The final state with the largest rate, J/psi rho(0)(770), is used to measure the CP-violating angle 2 beta(eff) to be (41.7 +/- 9.6(-6.3)(+2.8)).. This result can be used to limit the size of penguin amplitude contributions to CPviolation measurements in, for example, (B-0) over bar -> J/psi pi(+)pi(-) decays. Assuming approximate SU(3) flavour symmetry and neglecting higher order diagrams, the shift in the CP-violating phase phi(s) limited to be within the interval [-1.05 degrees, + 1.18 degrees] at 95% confidence level. Changes to the limit due to SU(3) symmetry breaking effects are also discussed.
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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. (2019). Measurement of the CP-violating phase phi(s) from B-s(0) -> J/psi pi(+)pi(-) decays in 13 TeV pp collisions. Phys. Lett. B, 797, 134789–12pp.
Abstract: Decays of B-s(0) and (B) over bar (0)(s) mesons into J/psi pi(+)pi(-) final states are studied in a data sample corresponding to 1.9 fb(-1) of integrated luminosity collected with the LHCb detector in 13 TeV pp collisions. A time-dependent amplitude analysis is used to determine the final-state resonance contributions, the CP-violating phase phi(s) = -0.057 +/- 0.060 +/- 0.011 rad, the decay-width difference between the heavier mass B-s(0) eigenstate and the B-0 meson of -0.050 +/- 0.004 +/- 0.004 ps(-1), and the CP-violating parameter vertical bar lambda vertical bar = 1.01(-0.06)(+0.08) +/- 0.03, where the first uncertainty is statistical and the second systematic. These results are combined with previous LHCb measurements in the same decay channel using 7 TeV and 8 TeV pp collisions obtaining phi(s) = 0.002 +/- 0.044 +/- 0.012 rad, and vertical bar lambda vertical bar = 0.949 +/- 0.036 +/- 0.019.
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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 CP-Violating Phase phi(s) in (B)over-bar(s)(0) -> Ds+Ds- Decays. Phys. Rev. Lett., 113(21), 211801–9pp.
Abstract: We present a measurement of the CP-violating weak mixing phase phi(s) using the decay (B) over bar (0)(s) -> Ds+Ds- in a data sample corresponding to 3.0 fb(-1) of integrated luminosity collected with the LHCb detector in pp collisions at center-of-mass energies of 7 and 8 TeV. An analysis of the time evolution of the system, which does not use the constraint vertical bar lambda vertical bar = 1 to allow for the presence of CP violation in decay, yields phi(s) = 0.02 +/- 0.17(stat) +/- 0.02(syst) rad, vertical bar lambda vertical bar = 0.91(-0.15)(+0.18)(stat) +/- 0.02(syst). This result is consistent with the standard model expectation.
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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 CP-violating phase phi(s) in (B)over-bar(s)(0) -> J / psi pi(+)pi(-) decays. Phys. Lett. B, 736, 186–195.
Abstract: The mixing-induced CP-violating phase phi(s) in B-s(0) and (B) over bar (0)(s) decays is measured using the J / psi pi(+)pi(-) final state in data, taken from 3 fb(-1) of integrated luminosity, collected with the LHCb detector in 7 and 8 TeV centre-of-mass pp collisions at the LHC. A time-dependent flavour-tagged amplitude analysis, allowing for direct CP violation, yields a value for the phase phi(s) = 70 +/- 68 +/- 8 mrad. This result is consistent with the Standard Model expectation and previous measurements.
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