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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. (2019). Measurement of the branching fraction and CP asymmetry in B plus . J/.. plus decays. Eur. Phys. J. C, 79(6), 537–13pp.
Abstract: The branching fraction and direct CP asymmetry of the decay B +. J/.. + are measured using protonproton collision data collected with the LHCb detector at centre- of- mass energies of 7 and 8 TeV, corresponding to a total integrated luminosity of 3 fb – 1. The following results are obtained: ( B +. J/.. +) = ( 3.81 + 0.25 – 0.24 +/- 0.35) x 10 – 5, ACP ( B +. J/.. +) = – 0.045 + 0.056 – 0.057 +/- 0.008, where the first uncertainties are statistical and the second systematic. Both measurements are the most precise to date.
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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. (2019). Measurement of the branching fractions of the decays D+ -> K-K+K+, D+ -> pi-pi(+) K+ and D-s(+) -> pi-K+K+. J. High Energy Phys., 03(3), 176–24pp.
Abstract: The branching fractions of the doubly Cabibbo-suppressed decays D+ ! K, D+ ! and D+ s ! are measured using the decays D+ ! K and D+ s ! K as normalisation channels. The measurements are performed using proton-proton collision data collected with the LHCb detector at a centre-of-mass energy of 8TeV, corresponding to an integrated luminosity of 2.0 fb. The results are B (D+ ! K) B (D+ ! K) = (6 : 541 0 : 025 0 : 042) 10 B (D+ ! ) B (D+ ! K) = (5 : 231 0 : 009 0 : 023) 10 B (D+ s ! ) B (D+ s ! K) = (2 : 372 0 : 024 0 : 025) 10 where the uncertainties are statistical and systematic, respectively. These are the most precise measurements up to date.
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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. (2019). Measurement of the Charm-Mixing Parameter y(CP). Phys. Rev. Lett., 122(1), 011802–10pp.
Abstract: A measurement of the charm-mixing parameter Y-CP using D-0 -> K+K-, D-0 -> pi(+)pi(-), and D-0 -> K-pi(+)decays is reported. The D-0 mesons are required to originate from semimuonic decays of B- and (B) over bar (0)mesons. These decays are partially reconstructed in a data set of proton-proton collisions at center-of-mass energies of 7 and 8 TeV collected with the LHCb experiment and corresponding to an integrated luminosity of 3 fb(-1). The y c p parameter is measured to be (0.57 +/- 0.13(stat) +/- 0.09(syst))%, in agreement with, and as precise as, the current world-average value.
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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. (2019). Measurement of the CP-violating phase phi(s) from B-s(0) -> J/psi pi(+)pi(-) decays in 13 TeV pp collisions. Phys. Lett. B, 797, 134789–12pp.
Abstract: Decays of B-s(0) and (B) over bar (0)(s) mesons into J/psi pi(+)pi(-) final states are studied in a data sample corresponding to 1.9 fb(-1) of integrated luminosity collected with the LHCb detector in 13 TeV pp collisions. A time-dependent amplitude analysis is used to determine the final-state resonance contributions, the CP-violating phase phi(s) = -0.057 +/- 0.060 +/- 0.011 rad, the decay-width difference between the heavier mass B-s(0) eigenstate and the B-0 meson of -0.050 +/- 0.004 +/- 0.004 ps(-1), and the CP-violating parameter vertical bar lambda vertical bar = 1.01(-0.06)(+0.08) +/- 0.03, where the first uncertainty is statistical and the second systematic. These results are combined with previous LHCb measurements in the same decay channel using 7 TeV and 8 TeV pp collisions obtaining phi(s) = 0.002 +/- 0.044 +/- 0.012 rad, and vertical bar lambda vertical bar = 0.949 +/- 0.036 +/- 0.019.
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ATLAS Collaboration(Aad, G. et al), Alvarez Piqueras, D., Aparisi Pozo, J. A., Bailey, A. J., Barranco Navarro, L., Cabrera Urban, S., et al. (2019). Measurement of the cross-section and charge asymmetry of W bosons produced in proton-proton collisions at root s=8 TeV with the ATLAS detector. Eur. Phys. J. C, 79(9), 760–25pp.
Abstract: This paper presents measurements of the W+->mu+nu and W-->mu-nu cross-sections and the associated charge asymmetry as a function of the absolute pseudorapidity of the decay muon. The data were collected in proton-proton collisions at a centre-of-mass energy of 8 TeV with the ATLAS experiment at the LHC and correspond to a total integrated luminosity of 20.2fb(-1). The precision of the cross-section measurements varies between 0.8 and 1.5% as a function of the pseudorapidity, excluding the 1.9% uncertainty on the integrated luminosity. The charge asymmetry is measured with an uncertainty between 0.002 and 0.003. The results are compared with predictions based on next-to-next-to-leading-order calculations with various parton distribution functions and have the sensitivity to discriminate between them.
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