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 CP violation in B-0 -> D-/+pi(+/-) decays. J. High Energy Phys., 06(6), 084–23pp.
Abstract: A measurement of the CP asymmetries S-f and S-(f) over bar in B-0 -> D--/+pi(+/-) decays is reported. The decays are reconstructed in a dataset collected with the LHCb experiment in proton-proton collisions at centre-of-mass energies of 7 and 8 TeV and corresponding to an integrated luminosity of 3.0 fb(-1). The CP asymmetries are measured to be S-f = 0.058 +/- 0.020(stat) +/- 0.011(syst) and S-(f) over bar = 0.038 +/- 0.020(stat) +/- 0.007(syst). These results are in agreement with, and more precise than, previous determinations. They are used to constrain angles of the unitarity triangle, vertical bar sin (2 beta + gamma)vertical bar and gamma, to intervals that are consistent with the current world-average values.
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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). Search for B-c(+) decays to two charm mesons LHCb Collaboration. Nucl. Phys. B, 930, 563–582.
Abstract: A search for decays of B-c(+) mesons to two charm mesons 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 centre-of-mass energies of 7 and 8 TeV. The decays considered are B-c(+)-> D-(s)(()*())(+) (D) over bar (()*()0) and Bc(+)-> D-(s)(()*D-)+(()*())(0), which are normalised to high-yield B+-> D-(s)(+)(D) over bar (0)decays. No evidence for a signal is found and limits are set on twelve B-c(+) decay modes.
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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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BABAR Collaboration(Lees, J. P. et al), Martinez-Vidal, F., & Oyanguren, A. (2018). Study of Upsilon(1S) radiative decays to gamma pi(+)pi(-) and gamma K+ K-. Phys. Rev. D, 97(11), 112006–17pp.
Abstract: We study the Upsilon(1S) radiative decays to gamma pi(+)pi(-) and gamma K+K- using data recorded with the BABAR detector operating at the SLAC PEP-11 asymmetric-energy e(+)e(-) collider at center-of-mass energies at the Upsilon(2S) and Upsilon(3S) resonances. The Upsilon(1S) resonance is reconstructed from the decay Upsilon(nS) -> pi(+)pi(-) Upsilon(1S), n =2, 3. Branching fraction measurements and spin-parity analyses of Upsilon(1S) radiative decays are reported for the I = 0 S-wave and f(2) (1270) resonances in the pi(+)pi(-) mass spectrum, the f'(2) (1525) and f(0) (1500) in the K+K mass spectrum, and the f(0)(1710) in both.
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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 Rare Decay Sigma(+) -> p mu(+)mu(-). Phys. Rev. Lett., 120(22), 221803–10pp.
Abstract: A search for the rare decay Sigma(+) -> p mu(+)mu(-) is performed using pp collision data 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). An excess of events is observed with respect to the background expectation, with a signal significance of 4.1 standard deviations. No significant structure is observed in the dimuon invariant mass distribution, in contrast with a previous result from the HyperCP experiment. The measured Sigma(+) -> p mu(+)mu(-) branching fraction is (2.2(-1.3)(+1.8)) x 10(-8), where statistical and systematic uncertainties are included, which is consistent with the standard model prediction.
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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). Studies of the resonance structure in D-0 -> K-/+ pi(+/-) pi(+/-) pi(-/+) decays. Eur. Phys. J. C, 78(6), 443–31pp.
Abstract: Amplitude models are constructed to describe the resonance structure of D-0 -> K-pi(+) pi(+) pi(-) and D-0 -> K+ pi(-)pi(-)pi(+) decays using pp collision data collected at centre-of-mass energies of 7 and 8 TeV with the LHCb experiment, corresponding to an integrated luminosity of 3.0 f b(-1). The largest contributions to both decay amplitudes are found to come from axial resonances, with decay modes D-0 -> a(1)(1260)(+) K- and D-0 -> K-1(1270/1400)(+)pi(-) being prominent in D-0 -> K-pi(+) pi(+) pi(-) and D-0 -> K+pi(-)pi(-)pi(+), respectively. Precise measurements of the lineshape parameters and couplings of the a(1)(1260)(+), K-1(1270)(-) and K(1460)(-) resonances are made, and a quasi model-independent study of the K(1460)(-) resonance is performed. The coherence factor of the decays is calculated from the amplitude models to be R-K3 pi = 0.459 +/- 0.010 (stat) +/- 0.012 (syst) +/- 0.020 (model), which is consistent with direct measurements. These models will be useful in future measurements of the unitary-triangle angle gamma and studies of charm mixing and CP violation.
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