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LHCb Collaboration(Aaij, R. et al), Oyanguren, A., & Ruiz Valls, P. (2013). Search for CP violation in D+ -> phi pi(+) and D-s(+) -> K-S(0)pi(+) decays. J. High Energy Phys., 06(6), 112–20pp.
Abstract: A search for C P violation in D+ -> phi pi(+) decays is performed using data collected in 2011 by the LHCb experiment corresponding to an integrated luminosity of 1.0 fb(-1) at a centre of mass energy of 7 TeV. The CP-violating asymmetry is measured to be (-0.04 +/- 0.14 +/- 0.14)% for candidates with K-K+ mass within 20 MeV/c(2) of the phi meson mass. A search for a CP-violating asymmetry that varies across the phi mass region of the D+ -> K-K+pi(+) Dalitz plot is also performed, and no evidence for CP violation is found. In addition, the CP asymmetry in the D-s(+) -> K-S(0)pi(+) decay is measured to be (0.61 +/- 0.83 +/- 0.14)%.
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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). Search for CP Violation in D-s(+) -> K-S(0)pi(+), D+ -> (KSK+)-K-0, and D+ -> phi pi(+) Decays. Phys. Rev. Lett., 122(19), 191803–11pp.
Abstract: A search for charge-parity (CP) violation in Cabibbo-suppressed D-s(+) -> K-S(0)pi(+), D+ -> (KSK+)-K-0, and D+ -> phi pi(+) decays is reported using proton-proton collision data, corresponding to an integrated luminosity of 3.8 fb(-1), collected at a center-of-mass energy of 13 TeV with the LHCb detector. High-yield samples of kinematically and topologically similar Cabibbo-favored D-(s())+ decays are analyzed to subtract nuisance asymmetries due to production and detection effects, including those induced by CP violation in the neutral kaon system. The results are A(CP)(D-s(+) -> K-S(0)pi(+)) = (1.3 +/- 1.9 +/- 0.5) x 10(-3), A(CP)(D+ -> (KSK+)-K-0) = (-0.09 +/- 0.65 +/- 0.48) x 10(-3), A(CP)(D+ -> phi pi(+)) = (0.05 +/- 0.42 +/- 0.29) x 10(-3), where the first uncertainties are statistical and the second systematic. They are the most precise measurements of these quantities to date, and are consistent with CP symmetry. A combination with previous LHCb measurements, based on data collected at 7 and 8 TeV, is also reported.
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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). Observation of CP Violation in Charm Decays. Phys. Rev. Lett., 122(21), 211803–12pp.
Abstract: A search for charge-parity (CP) violation in D-0 -> K-K+ and D-0 -> pi(-)pi(+) decays is reported, using pp collision data corresponding to an integrated luminosity of 5.9 fb(-1) collected at a center-of-mass energy of 13 TeV with the LHCb detector. The flavor of the charm meson is inferred from the charge of the pion in D* (2010)(+) -> D-0 pi(+) decays or from the charge of the muon in (B) over bar -> D-0 mu(-)(nu) over bar X-mu decays. The difference between the CP asymmetries in D-0 -> K-K+ and D-0 -> pi(-)pi(+) decays is measured to be Delta A(CP) = [-18.2 +/- 3.2(stat) +/- 0.9(syst)] x 10(-4) for pi-tagged and Delta A(CP) = [-9 +/- 8(stat) +/- 5(syst)] x 10(-4) for mu-tagged D-0 mesons. Combining these with previous LHCb results leads to Delta A(CP) = (-15.4 +/- 2.9) x 10(-4), where the uncertainty includes both statistical and systematic contributions. The measured value differs from zero by more than 5 standard deviations. This is the first observation of CP violation in the decay of charm hadrons.
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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 branching fractions of charmless four-body Lambda(0)(b) and Xi(0)(b) decays. J. High Energy Phys., 02(2), 098–25pp.
Abstract: A search for charmless four-body decays of Lambda(0)(b) and Xi(0)(b) baryons with a proton and three charged mesons (either kaons or pions) in the final state is performed. The data sample used was recorded in 2011 and 2012 with the LHCb experiment and corresponds to an integrated luminosity of 3 fb(-1). Six decay modes are observed, among which Lambda(0)(b) -> pK(-) pi(+)pi(-), Lambda(0)(b) -> pK(-)K(+)K(-), Xi(0)(b) pK(-) pi(+)pi(-) and Xi(0)(b) pK(-)pi K-+(-) are established for the first time. Their branching fractions (including the ratio of hadronisation fractions in the case of the Xi(0)(b) baryon) are determined relative to the Lambda(0)(b) -> Lambda(+)(c)pi(-) decay.
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LHCb Collaboration(Aaij, R. et al), Jashal, B. K., Martinez-Vidal, F., Oyanguren, A., Rebollo De Miguel, M., Remon Alepuz, C., et al. (2023). Search for CP violation using (T)over-cap-odd correlations in B0 → p(p)over-barK+ π- decays. Phys. Rev. D, 108(3), 032007–16pp.
Abstract: A search for CP and P violation in charmless four-body B-0 -> p (p) over barK(+)pi(-) decays is performed using triple-product asymmetry observables. It is based on proton-proton collision data collected by the LHCb experiment at center-of-mass energies of 7, 8 and 13 TeV, corresponding to a total integrated luminosity of 8.4 fb(-1). The CP- and P-violating asymmetries are measured both in the integrated phase space and in specific regions. No evidence is seen for CP violation. P-parity violation is observed at a significance of 5.8 standard deviations.
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