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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). Study of Bc+ → χc π+ decays. J. High Energy Phys., 02(2), 173–30pp.
Abstract: A study of B-c(+) -> chi(c) pi(+) decays is reported using proton-proton collision data, collected with the LHCb detector at centre-of-mass energies of 7, 8, and 13TeV, corresponding to an integrated luminosity of 9 fb(-1). The decay B-c(+) -> chi(c2)pi(+) is observed for the first time, with a significance exceeding seven standard deviations. The relative branching fraction with respect to the B-c(+) -> J/psi pi(+) decay is measured to be BBc+ ->chi c2 pi+/BBc+ -> (J/psi pi+) = 0.37 +/- 0.06 +/- 0.02 +/- 0.01, where the first uncertainty is statistical, the second is systematic, and the third is due to the knowledge of the chi(c2) -> J/psi gamma branching fraction. No significant B-c(+) -> chi(+)(c1 pi) signal is observed and an upper limit for the relative branching fraction for the B-c(+) -> chi(c1)pi(+) and B-c(+) -> chi(c2)pi(+) decays of BBc+ ->chi c1 pi+/BBc+ -> chi(c2)pi(+) < 0.49 is set at the 90% confidence level.
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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 B-s(0) -> J/psi (KsK +/-)-K-0 pi(-/+) decay. J. High Energy Phys., 07(7), 140–29pp.
Abstract: Decays of the form B-s(0) -> J/psi K(s)(0)h(+)h((1)-) (h((1)) = K, pi) are searched for in proton-proton collision data corresponding to an integrated luminosity of 1.0 fb(-1) recorded with the LHCb detector. The first observation of the B-s(0) -> J/psi (KsK +/-)-K-0 pi(-/+) decay is reported, with significance in excess of 10 standard deviations. The B-0 -> J/psi (KsK+K-)-K-0 decay is also observed for the first time. The branching fraction of B-s(0) -> J/psi K(s)(0)h(+)h((1)-) is determined, to significantly better precision than previous measurements, using B-0 -> J/psi K(s)(0)h(+)h((1)-) as a normalisation channel. Branching fractions and upper limits of the other B-(s)(0) -> J/psi K-s(0)pi(+)pi(-) (s modes are determined relative to that of the B-0 -> J/psi K-s(0)pi(+)pi(-) decay.
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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). Observation of B-s(0) -> K* (+/-) K -/+ and evidence for B-s(0) -> K*(-) pi(+) decays. New J. Phys., 16, 123001–18pp.
Abstract: Measurements of the branching fractions of B-s(0) -> K*K-+/-(-/+) and B-s(0) -> K*(+/-) pi(-/+) decays are performed using a data sample corresponding to 1.0 fb(-1) of protonproton collision data collected with the LHCb detector at a centre-of- mass energy of 7 TeV, where the K*(+/-) mesons are reconstructed in the K-s(0) pi(+/-) final state. The first observation of the B-s(0) -> K*(+/-) K--/+ decay and the first evidence for the B-s(0) -> K*(-) pi(+) decay are reported with branching fractions B(B-s(0) -> K*K-+/-(-/+)) = (12.7 +/- 1.9 +/- 1.9) x 10(-6) , B(B-s(0) -> K*(-) pi(+)) = (3.3 +/- 1.1 +/- 0.5) x 10(-6) , where the first uncertainties are statistical and the second are systematic. In addition, an upper limit of B(B-0 -> K*K-+/-(-/+)) < 0.4 (0.5) x 10(-6) is set at 90% (95%) confidence level.
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LHCb Collaboration(Aaij, R. et al), Martinez-Vidal, F., Oyanguren, A., Ruiz Valls, P., & Sanchez Mayordomo, C. (2015). Study of eta-eta ' mixing from measurement of B-(s)(0) -> J/psi eta((')) decay rates. J. High Energy Phys., 01(1), 024–24pp.
Abstract: A study of B and B-s(0) meson decays into J/psi eta and J/psi eta' final states is performed using a data set of proton-proton collisions at centre-of-mass energies of 7 and 8 TeV, collected by the LCHb experiment and corresponding to 3.0 fb(-1) of integrated luminosity. The decay B-0 -> J/psi eta' is observed for the first time. The following ratios of branching fractions are measured: B(B-0 -> J psi eta')/B(B-s(0) -> J psi eta') = (2.28 +/- 0.65 (stat) +/- 0.010 (syst) +/- 0.13 (f(s)/f(d)) x 10(-2) , B(B-0 -> J psi eta')/B(B-s(0) -> J psi eta') = (1.85 +/- 0.65 (stat) +/- 0.09 (syst) +/- 0.11 (f(s)/f(d)) x 10(-2) where the third uncertainty is related to the present knowledge of f(s)/f(d), the ratio between the probabilities for a b quark to form a B-s(0) or a B-0 meson. The branching fraction ratios are used to determine the parameters of eta-eta' meson mixing. In addition, the first evidence for the decay B-s(0) -> psi(2S)' is reported, and the relative branching fraction is measured, B(B-s(0) -> psi(2S)eta')/B(B-s(0) -> J psi eta') = (38.7 +/- 9.0 (stat) +/- 1.3 (syst) +/- 0.9(B)) x 10(-2), where the third uncertainty is due to the limited knowledge of the branching fractions of J/psi and psi(2S) mesons.
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LHCb Collaboration(Aaij, R. et al), Martinez-Vidal, F., Oyanguren, A., Ruiz Valls, P., & Sanchez Mayordomo, C. (2015). Determination of the branching fractions of B-s(0) -> D-s(-/+) K-/+ and B-0 -> Ds-K+. J. High Energy Phys., 05(5), 019–16pp.
Abstract: Measurements are presented of the branching fractions of the decays B-s(0) -> D-s(-/+) K--/+ and B-0 -> Ds-K+ relative to the decays B-s(0) -> D-s(-)pi(+) and B-0 -> D-s(-)pi(+), respectively. The data used correspond to an integrated luminosity of 3.0 fb(-1) of proton-proton collisions. The ratios of branching fractions are B(B-s(0) -> D-s(-/+) K--/+)/B(B-s(0) -> D-s(-)pi(+)) = 0.0752 +/- 0.0015 +/- 0.0019 and B(B-0 -> Ds-K+)/B(B-0 -> D-pi(+)) = 0.0129 +/- 0.0005 +/- 0.0008, where the uncertainties are statistical and systematic, respectively.
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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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LHCb Collaboration(Aaij, R. et al), Martinez-Vidal, F., Oyanguren, A., Ruiz Valls, P., & Sanchez Mayordomo, C. (2015). Differential branching fraction and angular analysis of Lambda(0)(b) -> Lambda mu(+)mu(-) decays. J. High Energy Phys., 06(6), 115–29pp.
Abstract: The differential branching fraction of the rare decay Lambda(0)(b) -> Lambda mu(+)mu(-) is measured as a function of q(2), the square of the dimuon invariant mass. The analysis is performed using proton-proton collision data, corresponding to an integrated luminosity of 3.0 fb(-1), collected by the LHCb experiment. Evidence of signal is observed in the q(2) region below the square of the J/psi mass. Integrating over 15 < q(2) < 20 GeV2/c(4) the differential branching fraction is measured as dB(Lambda(0)(b) -> Lambda mu(+)mu(-))/dq(2) = (1.18(-0.08)(+0.09) +/- 0.03 +/- 0.27) x 10(-7) (GeV2/c(4))(-1) where the uncertainties are statistical, systematic and due to the normalisation mode Lambda(0)(b) -> J/psi Lambda , respectively. In the q(2) intervals where the signal is observed, angular distributions are studied and the forward-backward asymmetries in the dimuon (A(FB)(l)) and hadron (A(FB)(h)) systems are measured for the first time. In the range 15 < q(2) < 20GeV(2)/c(4) they are found to be A(FB)(l) = -0.05 +/- 0.09 (stat) +/- 0.03 (syst) and A(FB)(h) = -0.29 +/- 0.07 (stat) +/- 0.03 (syst).
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LHCb Collaboration(Aaij, R. et al), Martinez-Vidal, F., Oyanguren, A., Ruiz Valls, P., & Sanchez Mayordomo, C. (2015). First observation and measurement of the branching fraction for the decay B-s(0) -> D-s*K-/+(+/-). J. High Energy Phys., 06(6), 130–16pp.
Abstract: The first observation of the B-s(0) -> D-s*(-/+) K-+/- decay is reported using 3.0 fb(-1) of proton-proton collision data collected by the LHCb experiment. The D-s*(-/+) mesons are reconstructed through the decay chain D-s*(-/+) -> gamma D-s(-/+) ((KK +/-)-K--/+pi(-/+)). The branching fraction relative to that for B-s(0) -> D-s*(-)pi(+) decays is measured to be B (B-s(0) -> D-s*K--/+(+/-))/B(B-s(0) -> D-s*(-)pi(+)) = 0.068 +/- 0.005(-0.002)(+0.003), where the first uncertainty is statistical and the second is systematic. Using a recent measurement of B(B-s(0) -> D-s*(-)pi(+)), the absolute branching fraction of B-s(0) -> Ds*K--/+(+/-) is measured as B(B-s(0) -> D*K--/+(+/-)) = (16.3 +/- 1.2(stat)(-0.5)(+0.7)(syst) +/- 4.8(norm)) x 10(-5), where the third uncertainty is due to the uncertainty on the branching fraction of the normalisation channel.
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LHCb Collaboration(Aaij, R. et al), Martinez-Vidal, F., Oyanguren, A., Ruiz Valls, P., & Sanchez Mayordomo, C. (2015). Search for the decay B-s(0) -> (D)over-bar(0) f(0)(980). J. High Energy Phys., 08(8), 005–19pp.
Abstract: A search for B-s(0) -> (D) over bar (0) f(0)(980) decays is performed using 3.0 fb(1-) of pp collision data recorded by the LHCb experiment during 2011 and 2012. The f(0)(980) meson is reconstructed through its decay to the pi(+)pi(-) final state in the mass window 900 MeV/c(2) < m (pi(+)pi(-)) < 1080 MeV/c(2). No significant signal is observed. The first upper limits on the branching fraction of B (B-s(0) -> (D) over bar (0) f(0)(980)) < 3.1 (3.4) x 10(-6) are set at 90% (95 %) confidence level.
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