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LHCb Collaboration(Aaij, R. et al), Jashal, B. K., Martinez-Vidal, F., Oyanguren, A., Remon Alepuz, C., & Ruiz Vidal, J. (2021). Search for the doubly charmed baryon Omega(+)(cc). Sci. China-Phys. Mech. Astron., 64(10), 101062–12pp.
Abstract: A search for the doubly charmed baryon Omega(+)(cc) with the decay mode Omega(+)(cc) -> Xi K-+(c)-pi(+) is performed using proton-proton collision data at a centre-of-mass energy of 13 TeV collected by the LHCb experiment from 2016 to 2018, corresponding to an integrated luminosity of 5.4 fb(-1). No significant signal is observed within the invariant mass range of 3.6 to 4.0GeV/c(2). Upper limits are set on the ratio R of the production cross-section times the total branching fraction of the Omega(+)(cc) -> Xi K-+(c)-pi(+) decay with respect to the Xi(++)(cc) -> Lambda K-+(c)-pi(+)pi(+) decay. Upper limits at 95% credibility level for R in the range 0.005 to 0.11 are obtained for different hypotheses on the Omega(+)(cc) mass and lifetime in the rapidity range from 2.0 to 4.5 and transverse momentum range from 4 to 15 GeV/c.
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LHCb Collaboration(Aaij, R. et al), Jashal, B. K., Martinez-Vidal, F., Oyanguren, A., Remon Alepuz, C., & Ruiz Vidal, J. (2022). Study of charmonium and charmonium-like contributions in B+ -> J/psi eta K+ decays. J. High Energy Phys., 04(4), 046–29pp.
Abstract: A study of B+ -> J/psi eta K+ decays, followed by J/psi -> mu(+)mu(-) and eta -> gamma gamma, is performed using a dataset collected with the LHCb detector in proton-proton collisions at centre-of-mass energies of 7, 8 and 13 TeV, corresponding to an integrated luminosity of 9 fb(-1). The J/psi eta mass spectrum is investigated for contributions from charmonia and charmonium-like states. Evidence is found for the B+ -> (psi(2)(3823) -> J/psi eta)K+ and B+ -> (psi(4040) -> J/psi eta)K+ decays with significance of 3.4 and 4.7 standard deviations, respectively. This constitutes the first evidence for the psi(2)(3823) -> J/psi eta decay.
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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 chi(b) (3 P) mass and of the relative rate of chi(b1) (1 P) and chi(b2) (1 P) production. J. High Energy Phys., 10(10), 088–22pp.
Abstract: The production of chi(b) mesons in proton-proton collisions is studied using a data sample collected by the LHCb detector, at centre-of-mass energies of root s = 7 and 8 TeV and corresponding to an integrated luminosity of 3.0 fb(-1). The chi(b) mesons are identified through their decays to Upsilon(1 S)gamma and Upsilon(2 S)gamma using photons that converted to e(+)e (-) pairs in the detector. The relative prompt production rate of chi(b1)(1 P) and chi(b2)(1 P) mesons is measured as a function of the Upsilon(1 S) transverse momentum in the chi(b) rapidity range 2.0 < y < 4.5. A precise measurement of the chi(b) (3 P) mass is also performed. Assuming a mass splitting between the chi(b1)(3 P) and the chi(b2)(3 P) states of 10.5 MeV/c(2), the measured mass of the chi(b1)(3 P) meson is m (chi(b1)(3 P)) = 10515.7(-3.9)(+2.2)(stat)(-2.1)(+1.5)(syst) MeV/c(2).
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LHCb Collaboration(Aaij, R. et al), Martinez-Vidal, F., Oyanguren, A., Ruiz Valls, P., & Sanchez Mayordomo, C. (2014). Study of production and cold nuclear matter effects in pPb collisions at=5 TeV. J. High Energy Phys., 07(7), 094–19pp.
Abstract: Production of mesons in proton-lead collisions at a nucleon-nucleon centre-of-mass energy = 5 TeV is studied with the LHCb detector. The analysis is based on a data sample corresponding to an integrated luminosity of 1.6 nb(-1). The mesons of transverse momenta up to 15 GeV/c are reconstructed in the dimuon decay mode. The rapidity coverage in the centre-of-mass system is 1.5 < y < 4.0 (forward region) and -5.0 < y < -2.5 (backward region). The forward-backward production ratio and the nuclear modification factor for (1S) mesons are determined. The data are compatible with the predictions for a suppression of (1S) production with respect to proton-proton collisions in the forward region, and an enhancement in the backward region. The suppression is found to be smaller than in the case of prompt J/psi mesons.
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LHCb Collaboration(Aaij, R. et al), Martinez-Vidal, F., Oyanguren, A., Ruiz Valls, P., & Sanchez Mayordomo, C. (2014). Study of the kinematic dependences of Lambda(0)(b) production in pp collisions and a measurement of the Lambda(0)(b) -> Lambda(+)(c)pi(-) branching fraction. J. High Energy Phys., 08(8), 143–19pp.
Abstract: The kinematic dependences of the relative production rates, f(Lambda b)(0)/f(d), of Lambda(0)(b) baryons and B-0 mesons are measured using Lambda(0)(b) -> Lambda(+)(c)pi(-) and (B) over bar (0) -> D+pi(-) decays. The measurements use proton-proton collision data, corresponding to an integrated luminosity of 1 fb(-1) at a centre-of-mass energy of 7 TeV, recorded in the forward region with the LHCb experiment. The relative production rates are observed to depend on the transverse momentum, pT, and pseudorapidity, eta, of the beauty hadron, in the studied kinematic region 1.5 < pT < 40 GeV/c and 2 < eta < 5. Using a previous LHCb measurement of f(Lambda b)(0)/f(d) in semileptonic decays, the branching fraction B (Lambda(0)(b) -> Lambda(+)(c)pi(-)) = (4.30 +/- 0.03(-0.11)(+0.12)+/- 0.26 +/- 0.21) x 10(-3) is obtained, where the first uncertainty is statistical, the second is systematic, the third is from the previous LHCb measurement of f(Lambda b)(0)/f(d) and the fourth is due to the (B) over bar (0) -> D+pi(-) branching fraction. This is the most precise measurement of a Lambda(0)(b) branching fraction to date.
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LHCb Collaboration(Aaij, R. et al), Martinez-Vidal, F., Oyanguren, A., Ruiz Valls, P., & Sanchez Mayordomo, C. (2015). Forward production of Upsilon mesons in pp collisions at root s=7 and 8 TeV. J. High Energy Phys., 11(11), 103–34pp.
Abstract: The production of Upsilon mesons in pp collisions at root s = 7 and 8 TeV is studied with the LHCb detector using data samples corresponding to an integrated luminosity of 1 fb(-1) and 2 fb(-1) respectively. The production cross-sections and ratios of cross-sections are measured as functions of the meson transverse momentum p and rapidity y, for p < 30 GeV/c and 2.0 < y < 4.5.
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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 exclusive gamma production cross-section in pp collisions at root s=7 TeV and 8 TeV. J. High Energy Phys., 09(9), 084–20pp.
Abstract: A study is presented of central exclusive production of gamma(n S) states, where the gamma (n S) resonances decay to the mu(+) mu(-) final state, using p p collision data recorded by the LHCb experiment. The cross-section is measured in the rapidity range 2 < y (gamma) < 4.5 where the muons are reconstructed in the pseudorapidity range 2 < eta (mu(+/-)) < 4.5. The data sample corresponds to an integrated luminosity of 2.9 fb(-1) and was collected at centreof- mass energies of 7TeV and 8TeV. The measured gamma(1 S) and gamma(2 S) production crosssections are sigma(pp -> p gamma(1S)p) = 9.0 +/- 1.7 pb and sigma(pp -> p gamma(2S)p) = 1.3 +/- 0.3 pb, where the first uncertainties are statistical and the second are systematic. The gamma (1S) cross-section is also measured as a function of rapidity and is found to be in good agreement with Standard Model predictions. An upper limit is set at 3.4 pb at the 95% confidence level for the exclusive gamma(3 S) production cross-section, including possible contamination from chi b (3P) -> gamma (3S)gamma decays.
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LHCb Collaboration(Aaij, R. et al), Martinez-Vidal, F., Oyanguren, A., Ruiz Valls, P., & Sanchez Mayordomo, C. (2016). Measurements of prompt charm production cross-sections in pp collisions at root s=13 TeV. J. High Energy Phys., 03(3), 159–43pp.
Abstract: Production cross-sections of prompt charm mesons are measured with the first data from pp collisions at the LHC at a centre-of-mass energy of 13 TeV. The data sample corresponds to an integrated luminosity of 4.98 +/- 0.19 pb(-1) collected by the LHCb experiment. The production cross-sections of D-0, D+, D (s) (+) , and D*+ mesons are measured in bins of charm meson transverse momentum, p(T), and rapidity, y, and cover the range 0 < p(T) < 15GeV/c and 2.0 < y < 4.5. The inclusive cross-sections for the four mesons, including charge conjugation, within the range of 1 < p(T) < 8 GeV/c are found to be sigma(pp -> D-0 X) = 2460 +/- 3 +/- 130 μb sigma(pp -> D+ X) = 1000 +/- 3 +/- 110 μb sigma(pp -> Ds+X) = 460 +/- 13 +/- 100 μb sigma(pp -> D*+ X) = 880 +/- 5 +/- 140 μb where the uncertainties are due to statistical and systematic uncertainties, respectively.
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LHCb Collaboration(Aaij, R. et al), Martinez-Vidal, F., Oyanguren, A., Ruiz Valls, P., & Sanchez Mayordomo, C. (2016). Production of associated Y and open charm hadrons in pp collisions at root s=7 and 8 TeV via double parton scattering. J. High Energy Phys., 07(7), 052–36pp.
Abstract: Associated production of bottomonia and open charm hadrons in pp collisions at root s = 7 and 8 TeV is observed using data corresponding to an integrated luminosity of 3 fb(-1) accumulated with the LHCb detector. The observation of five combinations, Y(1S)D-0, Y(2S)D-0, Y(1S)D+, Y(2S)D+ and Y(1S)D (s) (+) , is reported. Production crosssections are measured for Y(1S)D-0 and Y(1S)D+ pairs in the forward region. The measured cross-sections and the differential distributions indicate the dominance of double parton scattering as the main production mechanism.
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LHCb Collaboration(Aaij, R. et al), Martinez-Vidal, F., Oyanguren, A., Ruiz Valls, P., & Sanchez Mayordomo, C. (2016). Study of psi(2S) production and cold nuclear matter effects in pPb collisions at root s(NN)=5 TeV. J. High Energy Phys., 03(3), 133–21pp.
Abstract: The production of psi(2S) mesons is studied in dimuon final states using proton-lead (pPb) collision data collected by the LHCb detector. The data sample corresponds to an integrated luminosity of 1.6 nb(-1). The nucleon-nucleon centre-of-mass energy of the pPb collisions is root s(NN) = 5 TeV. The measurement is performed using psi(2S) mesons with transverse momentum less than 14 GeV/c and rapidity y in the ranges 1.5 < y < 4.0 and -5.0 < y < -2.5 in the nucleon-nucleon centre-of-mass system. The forward-backward production ratio and the nuclear modi fi cation factor are determined for psi(2S) mesons. Using the production cross-section results of psi(2S) and J/psi mesons from b-hadron decays, the b (b) over bar cross-section in pPb collisions at root s(NN) = 5 TeV is obtained.
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