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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 psi (2S) production cross-sections in proton-proton collisions at v s=7 and 13 TeV. Eur. Phys. J. C, 80(3), 185–23pp.
Abstract: The cross-sections of.(2S) meson production in proton-proton collisions at v s = 13 TeV are measured with a data sample collected by the LHCb detector corresponding to an integrated luminosity of 275 pb-1. The production cross-sections for prompt.(2S) mesons and those for.(2S) mesons from b-hadron decays (.(2S)-from-b) are determined as functions of the transverse momentum, pT, and the rapidity, y, of the.(2S) meson in the kinematic range 2 < pT < 20 GeV/c and 2.0 < y < 4.5. The production cross-sections integrated over this kinematic region are s(prompt.(2S), 13 TeV) = 1.430 +/- 0.005 (stat) +/- 0.099 (syst) μb, s(.(2S)-from-b, 13 TeV) = 0.426 +/- 0.002 (stat) +/- 0.030 (syst) μb. A new measurement of.(2S) production cross-sections in pp collisions at v s = 7 TeV is also performed using data collected in 2011, corresponding to an integrated luminosity of 614 pb-1. The integrated production cross-sections in the kinematic range 3.5 < pT < 14 GeV/c and 2.0 < y < 4.5 are s(prompt.(2S), 7 TeV) = 0.471 +/- 0.001 (stat) +/- 0.025 (syst) μb, s(.(2S)-from-b, 7 TeV) = 0.126 +/- 0.001 (stat) +/- 0.008 (syst) μb. All results show reasonable agreement with theoretical calculations.
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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 the eta(c)(1S) production cross-section in p p collisions at root s=13TeV. Eur. Phys. J. C, 80(3), 191–18pp.
Abstract: Using a data sample corresponding to an integrated luminosity of 2.0 fb-1, collected by the LHCb experiment, the production of the.c(1S) state in proton-proton collisions at a centre-of-mass energy of v s = 13 TeVis studied in the rapidity range 2.0 < y < 4.5 and in the transverse momentum range 6.5 < pT < 14.0GeV. The cross-section for prompt production of.c(1S) mesons relative to that of the J/. meson is measured using the p p decay mode and is found to be s.c(1S)/sJ/. = 1.69 +/- 0.15 +/- 0.10 +/- 0.18. The quoted uncertainties are, in order, statistical, systematic and due to uncertainties on the branching fractions of the J/.. p p and.c. p p decays. The prompt.c(1S) production cross-section is determined to be s.c( 1S) = 1.26 +/- 0.11 +/- 0.08 +/- 0.14 μb, where the last uncertainty includes that on the J/. meson cross-section. The ratio of the branching fractions of b-hadron decays to the.c(1S) and J/. states is measured to be Bb..c X /Bb. J/. X = 0.48 +/- 0.03 +/- 0.03 +/- 0.05, where the last uncertainty is due to those on the branching fractions of the J/.. p p and.c. p p decays. The difference between the J/. and.c(1S) masses is also determined to be 113.0 +/- 0.7 +/- 0.1MeV, which is the most precise single measurement of this quantity to date.
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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). Search for CP violation in Xi(+)(c) -> pK(-) pi(+) decays using model-independent techniques. Eur. Phys. J. C, 80(10), 986–16pp.
Abstract: A first search for CP violation in the Cabibbo-suppressed Xi(+)(c) -> pK(-) pi(+) decay is performed using both a binned and an unbinned model-independent technique in the Dalitz plot. The studies are based on a sample of protonproton collision data, corresponding to an integrated luminosity of 3.0 fb(-1), and collected by the LHCb experiment at centre-of-mass energies of 7 and 8 TeV. The data are consistent with the hypothesis of no CP violation.
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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. (2016). Amplitude analysis of B- -> D+pi(-)pi(-) decays. Phys. Rev. D, 94(7), 072001–23pp.
Abstract: The Dalitz plot analysis technique is used to study the resonant substructures of B- -> D+pi(-)pi(-) decays in a data sample corresponding to 3.0 fb(-1) of pp collision data recorded by the LHCb experiment during 2011 and 2012. A model-independent analysis of the angular moments demonstrates the presence of resonances with spins 1, 2 and 3 at high D+pi(-) mass. The data are fitted with an amplitude model composed of a quasi-model-independent function to describe the D+pi(-) S wave together with virtual contributions from the D*(2007)(0) and B*(0) states, and components corresponding to the D-2*(2460)(0), D-1*(2680)(0), D-3*(2760)(0) and D-2*(3000)(0) resonances. The masses and widths of these resonances are determined together with the branching fractions for their production in B- -> D+pi(-)pi(-) decays. The D+pi(-) S wave has phase motion consistent with that expected due to the presence of the D-0*(2400)(0) state. These results constitute the first observations of the D-3*(2760)(0) and D-2*(3000)(0) resonances, with significances of 10 sigma and 6.6 sigma, respectively.
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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. (2016). Study of B-c(+) decays to the K+K-pi(+) final state and evidence for the decay B-c(+) -> chi(c0)pi(+). Phys. Rev. D, 94(9), 091102–10pp.
Abstract: A study of B-c(+) -> K+K-pi(+) decays is performed for the first time using data corresponding to an integrated luminosity of 3.0 fb(-1) collected by the LHCb experiment in pp collisions at center-of-mass energies of 7 and 8 TeV. Evidence for the decay B-c(+) -> chi(c0)(K+K-)pi(+) is reported with a significance of 4.0 standard deviations, giving sigma(B-c(+))/sigma(B+) x B(B-c(+) -> chi(c0)pi+) = (9.8(-3.0)(+3.4)(stat) +/- 0.8(stat)) x 10(-6). Here B denotes a branching fraction while sigma(B-c(+)) and sigma(B+) are the production cross sections for B-c(+) and B+ mesons. An indication of (b) over barc weak annihilation is found for the region m(K-pi(+)) < 1.834 GeV/c(2), with a significance of 2.4 standard deviations.
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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 B-s(0) -> phi pi(+)pi(-) and evidence for B-0 -> phi pi(+)pi(-). Phys. Rev. D, 95(1), 012006–15pp.
Abstract: The first observation of the rare decay B-s(0) -> phi pi(+) pi(-) and evidence for B-0 -> phi pi(+) pi(-) are reported, using pp collision data recorded by the LHCb detector at center-of-mass energies root s = 7 and 8 TeV, corresponding to an integrated luminosity of 3 fb(-1). The branching fractions in the pi(+) pi(-) invariant mass range 400 < m(pi(+) pi(-)) < 1600 MeV/c(2) are [3.48 +/- 0.23 +/- 0.17 +/- 0.35 +/- x 10(-6)] and [1.82 +/- 0.25 +/- 0.41 +/- 0.14 +/- x 10(-7) for B-s(0) -> phi pi(+) pi(-) and B-0 -> phi pi(+) pi(-) respectively, where the uncertainties are statistical, systematic and from the normalization mode B-s(0)-> phi phi. A combined analysis of the pi(+) pi(-) mass spectrum and the decay angles of the final-state particles identifies the exclusive decays B-s(0) -> phi f(0)(980), B-s(0) -> phi f(2)(1270), and B-s(0) -> phi rho(0) with branching fractions of [1.12 +/- 0.16(-0.08)(+0.09) +/- 0.11] x 10(-6), [0.61 +/- 0.13(-0.05)(+0.12) +/- 0.06] x 10-6 and [2.7 +/- 0.7 +/- 0.2 +/- 0.2] x 10(-7), respectively.
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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). Measurements of charm mixing and CP violation using D-0 -> K-+/-pi(-/+) decays. Phys. Rev. D, 95(5), 052004–14pp.
Abstract: Measurements of charm mixing and CP violation parameters from the decay-time-dependent ratio of D-0 -> K+pi(-) to D-0 -> K-pi(+) decay rates and the charge-conjugate ratio are reported. The analysis uses (B) over bar -> D*(+) μX-, and charge-conjugate decays, where D *(+) -> D-0 pi(+), and D-0 -> K-+/-pi(-/+). The pp collision data are recorded by the LHCb experiment at center-of-mass energies root s = 7 and 8 TeV, corresponding to an integrated luminosity of 3 fb(-1). The data are analyzed under three hypotheses: (i) mixing assuming CP symmetry, (ii) mixing assuming no direct CP violation in the Cabibbo-favored or doubly Cabibbo-suppressed decay amplitudes, and (iii) mixing allowing either direct CP violation and/or CP violation in the superpositions of flavor eigenstates defining the mass eigenstates. The data are also combined with those from a previous LHCb study of D-0 -> K pi decays from a disjoint set of D*(+) candidates produced directly in pp collisions. In all cases, the data are consistent with the hypothesis of CP symmetry.
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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 B-+/- production asymmetry and the CP asymmetry in B-+/-> J/psi K-+/- decays. Phys. Rev. D, 95(5), 052005–13pp.
Abstract: The B-+/- meson production asymmetry in pp collisions is measured using B-+/- -> (D) over bar (0)pi(+) decays. The data were recorded by the LHCb experiment during Run 1 of the LHC at center- of- mass energies of ffiffiffi root s = 7 and 8 TeV. The production asymmetries, integrated over transverse momenta in the range 2 < p(T) < 30 GeV/c, and rapidities in the range 2.1 < y < 4.5 are measured to be A(prod)(B+, root s = 7 TeV) = (-0.41 +/- 0.49 +/- 0.10) x 10(- 2), A(prod)(B+, root s = 8 TeV = (- 0.53 +/- 0.31 +/- 0.10) x 10(-2), where the first uncertainties are statistical and the second are systematic. These production asymmetries are used to correct the raw asymmetries of (B+ -> J/psi K+) decays, thus allowing a measurement of the CP asymmetry, A(CP)(B+-> J/psi K+) = (0.09 +/- 0.27 +/- 0.07) x 10(-2)
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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). Search for long-lived scalar particles in B+-> K+chi(mu(+) mu(-)) decays. Phys. Rev. D, 95(7), 071101–9pp.
Abstract: A search for a long-lived scalar particle. is performed, looking for the decay B+ -> K+chi with chi ->mu(+)mu(-) pp collision data corresponding to an integrated luminosity of 3 fb(-1), collected by the LHCb experiment at center-of-mass energies of root s = 7 and 8 TeV. This new scalar particle, predicted by hidden sector models, is assumed to have a narrow width. The signal would manifest itself as an excess in the dimuon invariant mass distribution over the Standard Model background. No significant excess is observed in the accessible ranges of mass 250 < m(chi) < 4700 MeV/c(2) and lifetime 0.1 < tau(chi) < 1000 ps. Upper limits on the branching fraction B(B-broken vertical bar -> K-broken vertical bar chi(mu(vertical bar) mu(-))) at 95% confidence level are set as a function of m(chi) and tau(chi), varying between 2 x 10(-10) and 10(-7). These are the most stringent limits to date. The limits are interpreted in the context of a model with a light inflaton particle.
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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 B-c(+) -> J/psi D-(*()) K-(*()) decays. Phys. Rev. D, 95(3), 032005–12pp.
Abstract: A search for the decays B-c(+) -> J/psi D-(*()0) Kappa(+) and B-c(+) -> J/psi D-(*K)+*(0) is performed with data collected at the LHCb experiment corresponding to an integrated luminosity of 3 fb(-1). The decays B-c(+) -> J/psi(DK+)-K-0 and B-c(+) -> J/psi D*K-0(+) are observed for the first time, while first evidence is reported for the B-c(broken vertical bar) -> J/psi D*K-broken vertical bar(*0) and B-c(broken vertical bar) -> J/psi(DK)-K-broken vertical bar*(0) decays. The branching fractions of these decays are determined relative to the B-c(+) -> J/psi pi(+) decay. The B-c(+) mass is measured, using the J/psi(DK+)-K-0 final state, to be 6274.28 +/- 1.40(stat) +/- 0.32(syst) MeV/c(2). This is the most precise single measurement of the B-c(+) mass to date.
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