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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 the B-s(0) -> eta'phi decay. J. High Energy Phys., 05(5), 158–18pp.
Abstract: A search for the charmless B-s(0) -> eta'phi decay is performed using pp collision data collected by the LHCb experiment at centre-of-mass energies of 7 and 8TeV, corresponding to an integrated luminosity of 3 fb(-1). No signal is observed and upper limits on the B-s(0) -> eta'phi branching fraction are set to 0.82 x 10(-6) at 90% and 1.01 x 10(-6) at 95% confidence level.
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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 CP violation in the phase space of D-0 -> pi(+)pi(-)pi(+)pi(-) decays. Phys. Lett. B, 769, 345–356.
Abstract: A search for time-integrated CP violation in the Cabibbo-suppressed decay D-0 -> pi(+)pi(-)pi(+)pi(-) is performed using an unbinned, model-independent technique known as the energy test. This is the first application of the energy test in four-body decays. The search is performed for P-even CP asymmetries and, for the first time, is extended to probe the P-odd case. Using proton proton collision data corresponding to an integrated luminosity of 3.0 fb(-1) collected by the LHCb detector at centre-of-mass energies of root s = 7 TeV and 8 TeV, the world's best sensitivity to CP violation in this decay is obtained. The data are found to be consistent with the hypothesis of CP symmetry with a p-value of (4.6 +/- 0.5)% in the P-even case, and marginally consistent with a p-value of (0.6 +/- 0.2)% in the P-odd case, corresponding to a significance for CP non -conservation of 2.7 standard deviations.
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LHCb Collaboration(Aaij, R. et al), Martinez-Vidal, F., Oyanguren, A., Remon Alepuz, C., Ruiz Valls, P., & Sanchez Mayordomo, C. (2017). Observation of eta(c)(2S) -> p(p)over-bar and search for X(3872) -> p(p)over-bar decays. Phys. Lett. B, 769, 305–313.
Abstract: The first observation of the decay eta(c)(2S) -> p (p) over bar is reported using proton -proton collision data corresponding to an integrated luminosity of 3.0 fb(-1) recorded by the LHCb experiment at centre -of -mass energies of 7 and 8 TeV. The eta c(2S) resonance is produced in the decay B+ [c (c) over bar ]K+. The product of branching fractions normalised to that for the intermediate state, R-eta c,(2s), is measured to be R-eta c,(2s) equivalent to B(B+-> eta c (2S)K+) x B(eta c(2s)(2S) -> p<<(p)over bar> )/B(B+ -> J/psi k(+)) x B(J/psi -> p<<(p)over bar> ) = (1.58 +/- 0.33 +/- 0.09) x 10(-2), where the first uncertainty is statistical and the second systematic. No signals for the decays B+ -> X(3872)(-> p (p) over bar )K+ and B+ psi(3770)(-> p (p) over bar )K+ are seen, and the 95% confidence level upper limits on their relative branching ratios are found to be R-x(3872) < 0.25 x 10(-2) and R-psi(3770) < 0.10. In addition, the mass differences between the nc(1S) and the J/psi states, between the eta(c)(2S) and the eta(c)(2S) states, and the natural width of the psi(1S) are measured as M-J/psi – M-eta c(7s)= 110.2 +/- 0.5 +/- 0.9 MeV, M psi(2S) – M-eta c (2S) = 52.5 +/- 1.7 +/- 0.6 MeV, Gamma(eta c) (1s) = 34.0 +/- 1.9 +/- 1.3 MeV.
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BABAR Collaboration(Lees, J. P. et al), Martinez-Vidal, F., & Oyanguren, A. (2017). Measurement of the e(+) e(-) -> (KsK +/-)-K-0 pi(-/+)pi(0) and K-s(0) K-+/-pi(-/+)eta cross sections using initial-state radiation. Phys. Rev. D, 95(9), 092005–17pp.
Abstract: The processes e(+) e(-) -> (KsK +/-)-K-0 pi(-/+)pi(0) and e(+) e(-) -> K-s(0) K-+/-pi(-/+)eta are studied over a continuum of energies from threshold to 4 GeV with the initial-state photon radiation method. Using 454 fb(-1) of data collected with the BABAR detector at the SLAC PEP-II storage ring, the first measurements of the cross sections for these processes are obtained. The intermediate resonance structures from K-*0(K pi)(0), K*(892)(+/-)(K pi)(T),and (KsK +/-)-K-0 rho(-/+)are studied. The J/psi is observed in all of these channels, and corresponding branching fractions are measured.
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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). Study of the D(0)p amplitude in Lambda(0)(b) -> D(0)p pi(-) decays. J. High Energy Phys., 05(5), 030–43pp.
Abstract: An amplitude analysis of the decay Lambda(0)(b) -> D(0)p pi(-) is performed in the part of the phase space containing resonances in the D(0)p channel. The study is based on a data sample corresponding to an integrated luminosity of 3.0 fb(-1) of pp collisions recorded by the LHCb experiment. The spectrum of excited Lambda(+)(c) states that decay into D(0)p is studied. The masses, widths and quantum numbers of the Lambda(c)(2880)(+) and Lambda(c) (2940)(+) resonances are measured. The constraints on the spin and parity for the Lambda(c)(2940)(+) state are obtained for the first time. A near-threshold enhancement in the D(0)p amplitude is investigated and found to be consistent with a new resonance, denoted the Lambda(c) (2860)(+), of spin 3/2 and positive parity.
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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). Study of J/psi production in jets. Phys. Rev. Lett., 118(19), 192001–11pp.
Abstract: The production of J/psi mesons in jets is studied in the forward region of proton-proton collisions using data collected with the LHCb detector at a center-of-mass energy of 13 TeV. The fraction of the jet transverse momentum carried by the J/psi meson, z(J/psi) p(T) (J/psi) / p(T)(jet) is measured using jets with p(T)(jet) > 20 GeV in the pseudorapidity range 2.5 < eta(jet) < 4.0. The observed z(J/psi) distribution for J/psi mesons produced in b-hadron decays is consistent with expectations. However, the results for prompt J/psi production do not agree with predictions based on fixed-order nonrelativistic QCD. This is the first measurement of the p(T) fraction carried by prompt J/psi mesons in jets at any experiment.
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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). Evidence for the two-body charmless baryonic decay B+ -> p(Lambda)over-bar. J. High Energy Phys., 04(4), 162–18pp.
Abstract: A search for the rare two-body charmless baryonic decay B+ -> p (Lambda) over bar is performed with pp collision data, corresponding to an integrated luminosity of 3 fb(-1), collected by the LHCb experiment at centre-of-mass energies of 7 and 8 TeV. An excess of B+ -> p (Lambda) over bar candidates with respect to background expectations is seen with a statistical significance of 4.1 standard deviations, and constitutes the first evidence for this decay. The branching fraction, measured using the B+ -> K-S(0)pi(+) decay for normalisation, is B(B+ -> p (Lambda) over bar) = (2.4(-0.8)(+)(+1.0) +/- 0.3) x 10(-7), where the first uncertainty is statistical and the second systematic.
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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. (2017). Measurement of the B-s(0)-> mu(+) mu(-) Branching Fraction and Effective Lifetime and Search for B-0 ->mu(+) mu(-) Decays. Phys. Rev. Lett., 118(19), 191801–11pp.
Abstract: A search for the rare decays B-s(0)->mu(+)mu(-) and B-0 -> mu(+)mu(-) is performed at the LHCb experiment using data collected in pp collisions corresponding to a total integrated luminosity of 4.4 fb(-1). An excess of B-s(0) -> mu(+)mu- decays is observed with a significance of 7.8 standard deviations, representing the first observation of this decay in a single experiment. The branching fraction is measured to be B(B-s(0) -> mu(+)mu(-)) = (3.0 +/- 0.6(-0.2)(+)(0.3)) x 10(-9), where the first uncertainty is statistical and the second systematic. The first measurement of the B-s(0) -> mu(+)mu(-) effective lifetime, tau(B-s(0)-> mu(+) mu(-)) = 2.04 +/- 0.44 +/- 0.05 ps, is reported. No significant excess of B-0 -> mu(+)mu(-) decays is found, and a 95% confidence level upper limit, B(B-0 -> mu(+)mu(-) ) < 3.4 x 10(-10), is determined. All results are in agreement with the standard model expectations.
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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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LHCb Collaboration(Aaij, R. et al), Garcia Martin, L. M., Martinez-Vidal, F., Oyanguren, A., Remon Alepuz, C., Ruiz Valls, P., et al. (2017). New algorithms for identifying the flavour of B-0 mesons using pions and protons. Eur. Phys. J. C, 77(4), 238–15pp.
Abstract: Two new algorithms for use in the analysis of pp collision are developed to identify the flavour of B mesons at production using pions and protons from the hadronization process. The algorithms are optimized and calibrated on data, using B-0 -> D- pi(+) decays from pp collision data collected by LIICh at centre -of -mass energies of 7 and 8 TeV. The tagging power of the new pion algorithm is 60% greater than the previously available one; the algorithm using protons to identify the flavour of a B-0 meson is the first of its kind.
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