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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 Omega(0)(c) Baryon Lifetime. Phys. Rev. Lett., 121(9), 092003–10pp.
Abstract: We report a measurement of the lifetime of the Omega(0)(c) baryon using proton-proton collision data at center-of-mass energies of 7 and 8 TeV, corresponding to an integrated luminosity of 3.0 fb(-1) collected by the LHCb experiment. The sample consists of about 1000 Omega(-)(b) -> Omega(0)(c)mu(-)nu X-mu signal decays, where the Omega(0)(c) baryon is detected in the pK(-)K(-)pi(+) thorn final state and X represents possible additional undetected particles in the decay. The Omega(0)(c) lifetime is measured to be tau(Omega c0) = 268 +/- 24 +/- 10 +/- 2 fs, where the uncertainties are statistical, systematic, and from the uncertainty in the D+ lifetime, respectively. This value is nearly four times larger than, and inconsistent with, the current world-average value.
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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 Angular and CP Asymmetries in D-0 -> pi(+) pi(-) mu(+) mu(-) and D-0 -> K+ K- mu(+) mu(-) Decays. Phys. Rev. Lett., 121(9), 091801–10pp.
Abstract: The first measurements of the forward-backward asymmetry of the dimuon pair (A(FB)), the triple-product asymmetry (A(2 phi)), and the charge-parity-conjugation asymmetry (A(CP)), in D-0 -> pi(+) pi(-) mu(+) mu(-) and -> D-0 -> K+ K- mu(+) mu(-) decays are reported. They are performed using data from proton-proton collisions collected with the LHCb experiment from 2011 to 2016, corresponding to a total integrated luminosity of 5 fb(-1). The asymmetries are measured to be A(FB) (D-0 -> pi(+) pi(-) mu(+) mu(-)) = (3.3 +/- 3.7 +/- 0.6)%, A(2 phi) (D-0 -> pi(+) pi(-) mu(+) mu(-)) = (-0.6 +/- 3.7 +/- 0.6)%, A(CP) (D-0 -> pi(+) pi(-) mu(+) mu(-)) = (4.9 +/- 3.8 +/- 0.7)%, A(FB) (D-0 -> K+ K- mu(+) mu(-)) = (0 +/- 11 +/- 2 +/-)%, A(2 phi) (D-0 -> K+ K- mu(+) mu(-)) = (9 +/- 11 +/- 1)%, A(CP) (D-0 -> K+ K- mu(+) mu(-)) = (0 +/- 11 +/- 2)% where the first uncertainty is statistical and the second systematic. The asymmetries are also measured as a function of the dimuon invariant mass. The results are consistent 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). Observation of the decay Lambda(0)(b) -> psi(2S)p pi(-). J. High Energy Phys., 08(8), 131–18pp.
Abstract: The Cabibbo-suppressed decay Lambda(0)(b) -> psi(2S)p pi(-) is observed for the fi rst time using a data sample collected by the LHCb experiment in proton-proton collisions corresponding to 1.0, 2.0 and 1.9 fb(-1) of integrated luminosity at centre-of-mass energies of 7, 8 and 13TeV, respectively. The psi(2S) mesons are reconstructed in the mu(+)mu(-) fi nal state. The branching fraction with respect to that of the Lambda(0)(b) -> psi(2S)pK(-) decay mode is measured to be B (Lambda(0)(b) -> psi(2S)p pi(-))/B (Lambda(0)(b) -> psi(2S)pK(-)) = (11.44 +/- 1.3 +/- 0.2)%, where the fi rst uncertainty is statistical and the second is systematic. The psi(2S) p and psi(2S)pi(-) mass spectra are investigated and no evidence for exotic resonances is found.
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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 CP asymmetries in two-body B-(s)(0)-meson decays to charged pions and kaons. Phys. Rev. D, 98(3), 032004–23pp.
Abstract: The time-dependent CP asymmetries in B-0 -> pi(+)pi(-) and B-(s)(0) -> K+K- decays are measured using a data sample of p p collisions corresponding to an integrated luminosity of 3.0 fb(-1), collected with the LHCb detector at center-of-mass energies of 7 and 8 TeV. The same data sample is used to measure the time-integrated CP asymmetries in B-0 -> K+pi(-) and B-(s)(0) -> pi K-+(-) decays. The results are C pi+pi- = -0.34 +/- 0.06 +/- 0.01, S pi+pi- = -0.63 +/- 0.05 +/- 0.01, CK+K- = 0.20 +/- 0.06 +/- 0.02, SK+K- = 0.18 +/- 0.06 +/- 0.02, A(K+K-)(Delta Gamma) = -0.79 +/- 0.07 +/- 0.10, A(CP)(B0) = -0.084 +/- 0.004 +/- 0.003, and A(CP)(B0s) = 0.213 +/- 0.015 +/- 0.007, where the first uncertainties are statistical and the second systematic. Evidence for CP violation is found in the B-s(0) -> K+K- decay for the first time.
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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 D-s(+/-) production asymmetry in pp collisions at root s=7 and 8 TeV. J. High Energy Phys., 08(8), 008–21pp.
Abstract: The inclusive D-s(+/-) production asymmetry is measured in pp collisions collected by the LHCb experiment at centre-of-mass energies of root s = 7 and 8 TeV. Promptly produced D-s(+/-) mesons are used, which decay as D-s(+/-) -> phi pi(+/-), with phi -> K+ K-. The measurement is performed in bins of transverse momentum, pT, and rapidity, y, covering the range 2.5 < pT < 25 : 0 GeV/c and 2.0 < y < 4.5. No kinematic dependence is observed. Evidence of nonzero D-s(+/-) production asymmetry is found with a significance of 3.3 standard deviations.
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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 Lifetime of the Doubly Charmed Baryon Xi(++)(cc). Phys. Rev. Lett., 121(5), 052002–10pp.
Abstract: The first measurement of the lifetime of the doubly charmed baryon Xi(++)(cc) is presented, with the signal reconstructed in the final state Lambda K-+(c)-pi(+)pi(+). The data sample used corresponds to an integrated luminosity of 1.7 fb(-1), collected by the LHCb experiment in proton-proton collisions at a center-of-mass energy of 13 TeV. The Xi(++)(cc) lifetime is measured to be 0.256(-0.022)(+0.024) (stat) +/- 0.014(syst) ps.
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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 Upsilon production in pp collisions at root s=13 TeV. J. High Energy Phys., 07(7), 134–27pp.
Abstract: The production cross-sections of Upsilon(1S), Upsilon(2S) and Upsilon(3S) mesons in proton-proton collisions at root s = 13 TeV are measured with a data sample corresponding to an integrated luminosity of 277 +/- 11 pb(-1) recorded by the LHCb experiment in 2015. The Upsilon mesons are reconstructed in the decay mode Upsilon -> mu(+)mu(-). The differential production cross-sections times the dimuon branching fractions are measured as a function of the Upsilon transverse momentum, p(T) , and rapidity, y, over the range 0 < p(T) < 30 GeV/c and 2.0 < y < 4.5. The ratios of the cross-sections with respect to the LHCb measurement at root s = 8 TeV are also determined. The measurements are compared with theoretical predictions based on NRQCD.
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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). Evidence for the decay B-s(0) -> (K)over-bar(*0) mu(+)mu(-). J. High Energy Phys., 07(7), 020–24pp.
Abstract: A search for the decay B-s(0) -> (K) over bar (*0) mu(+) mu(-) is presented using data sets corresponding to 1.0, 2.0 and 1.6 fb(-1) of integrated luminosity collected during pp collisions with the LHCb experiment at centre-of-mass energies of 7, 8 and 13TeV, respectively. An excess is found over the background-only hypothesis with a significance of 3.4 standard deviations. The branching fraction of the B-s(0) -> (K) over bar (*0) mu(+) mu(-) decay is determined to be B(B-s(0) -> (K) over bar (*0) mu(+) mu(-)) = [2.9 +/- 1.0 (stat) +/- 0.2 (syst) +/- 0.3 (norm)] x 10(-8), where the first and second uncertainties are statistical and systematic, respectively. The third uncertainty is due to limited knowledge of external parameters used to normalise the branching fraction measurement.
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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). Amplitude Analysis of the Decay (B)over-bar(0 )-> K-S(0)pi(+)pi(- )and First Observation of the CP Asymmetry in (B)over-bar(0 )-> K* (892)(-)pi(+). Phys. Rev. Lett., 120(26), 261801–10pp.
Abstract: The time-integrated untagged Dalitz plot of the three-body hadronic charmless decay (B) over bar (0 )-> K-S(0)pi(+)pi(- ) is studied using a pp collision data sample recorded with the LHCb detector, corresponding to an integrated luminosity of 3.0 fb(-1). The decay amplitude is described with an isobar model. Relative contributions of the isobar amplitudes to the (B) over bar (0 )-> K-S(0)pi(+)pi(- ) decay branching fraction and CP asymmetries of the flavor-specific amplitudes are measured. The CP asymmetry between the conjugate (B) over bar (0 )-> K* (892)(-)pi(+) and (B) over bar (0 )-> K* (892)(-)pi(+) decay rates is determined to be -0.308 +/- 0.062.
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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 inelastic pp cross-section at a centre-of-mass energy of 13 TeV. J. High Energy Phys., 06(6), 100–18pp.
Abstract: The cross-section for inelastic proton-proton collisions at a centre-of-mass energy of 13 TeV is measured with the LHCb detector. The fiducial cross-section for inelastic interactions producing at least one prompt long-lived charged particle with momentum p > 2 GeV/c in the pseudorapidity range 2 < eta < 5 is determined to be sigma(acc) = 62.2 +/- 0.2 +/- 2.5 mb. The first uncertainty is the intrinsic systematic uncertainty of the measurement, the second is due to the uncertainty on the integrated luminosity. The statistical uncertainty is negligible. Extrapolation to full phase space yields the total inelastic proton-proton cross-section sigma(inel) = 75.4 +/- 3.0 +/- 4.5 mb, where the first uncertainty is experimental and the second due to the extrapolation. An updated value of the inelastic cross-section at a centre-of-mass energy of 7 TeV is also reported.
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