LHCb Collaboration(Aaij, R. et al), Garcia Martin, L. M., Henry, L., Martinez-Vidal, F., Oyanguren, A., Remon Alepuz, C., et al. (2017). Updated branching fraction measurements of B-(s)(0) -> K(S)(0)h(+)h'(-) decays. J. High Energy Phys., 11(11), 027–42pp.
Abstract: The charmless three-body decays B-(s)(0) -> K(S)(0)h(+)h '(-) (where h((')) – pi, K) are analysed using a sample of pp collision data recorded by the LHCb experiment, corresponding to an integrated luminosity of 3 fb(-1). The branching fractions are measured relative to that of the B-0 -> K-S(0) pi(+)pi(-) decay, and are determined to be: B(B-0 -> (KSK +/-)-K-0 pi(-/+))/B(B-0 -> K-S(0)pi(+)pi(-) = 0.123 +/- 0.009 (stat) +/- 0.015 (syst), B(B-0 -> (KSK+K-)-K-0)/B(B-0 -> K-S(0)pi(+)pi(-) = 0.549 +/- 0.018 (stat) +/- 0.033 (syst), B(B-S(0) -> K-S(0) pi(+)pi(-))/B(B-0 -> K-S(0)pi(+)pi(-)) = 0.191 +/- 0.027 (stat) +/- 0.031 (syst) +/- 0.011 (f(s)/f(d)), B(B-0 -> (KSK +/-)-K-0 pi(-/+))/B(B-0 -> K-S(0)pi(+)pi(-) = 1.70 +/- 0.07 (stat) +/- 0.11 (syst) +/- 0.10 (f(s)/f(d)), B(B-0 -> (KSK+K-)-K-0)/B(B-0 -> K-S(0)pi(+)pi(-) is an element of [0.008 – 0.051] at 90% confidence level, where f(s)/f(d) represents the ratio of hadronisation fractions of the B-s(0) and B-0 mesons.
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ATLAS Collaboration(Aaboud, M. et al), Alvarez Piqueras, D., Barranco Navarro, L., Cabrera Urban, S., Castillo Gimenez, V., Cerda Alberich, L., et al. (2017). Measurement of b-hadron pair production with the ATLAS detector in proton-proton collisions at root s=8 TeV. J. High Energy Phys., 11(11), 062–51pp.
Abstract: A measurement of b-hadron pair production is presented, based on a data set corresponding to an integrated luminosity of 11.4 fb(-1) of proton-proton collisions recorded at root s = 8TeV with the ATLAS detector at the LHC. Events are selected in which a b-hadron is reconstructed in a decay channel containing J = psi -> μmu, and a second b-hadron is reconstructed in a decay channel containing a muon. Results are presented in a fiducial volume de fined by kinematic requirements on three muons based on those used in the analysis. The fiducial cross section is measured to be 17.7 +/- 0.1(stat.) +/- 2.0(syst.) nb. A number of normalised differential cross sections are also measured, and compared to predictions from the PYTHIA8, HERWIG++, MADGRAPH5_AMC@NLO+PYTHIA8 and SHERPA event generators, providing new constraints on heavy flavour production.
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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 CP observables in B-+/- -> DK*(+/-) decays using two- and four-body D final states. J. High Energy Phys., 11(11), 156–27pp.
Abstract: Measurements of CP observables in B-+/- -> DK*(+/-) decays are presented, where D denotes a superposition of D-0 and (D) over bar (0) meson states. Decays of the D meson to K-pi(+), K-K+, pi(-)pi(+), K-pi(+)pi(-)pi(+) and pi(-)pi(+)pi(-)pi(+) are used and the K*(+/-) meson is reconstructed in the K-S(0)pi(+/-) final state. This analysis uses a data sample of pp collisions collected with the LHCb experiment, corresponding to integrated luminosities of 1 fb(-1), 2 fb(-1) and 1.8 fb(-1) at centre-of-mass energies root s = 7TeV, 8TeV and 13TeV, respectively. The sensitivity of the results to the CKM angle gamma is discussed.
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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 CP violation in B-0 -> J/psi K-S(0) and B-0 -> psi(2S) K-S(0) decays. J. High Energy Phys., 11(11), 170–18pp.
Abstract: A measurement is presented of decay-time-dependent CP violation in the decays B-0 -> J/psi K-S(0) and B-0 -> psi(2S) K-S(0), where the J/psi is reconstructed from two electrons and the psi(2S) from two muons. The analysis uses a sample of pp collision data recorded with the LHCb experiment at centre-of-mass energies of 7 and 8 TeV, corresponding to an integrated luminosity of 3 fb(-1). The CP-violation observables are measured to be C(B-0 -> J/psi K-S(0)) = 0.12 +/- 0.07 +/- 0.02, S(B-0 -> J/psi K-S(0)) = 0.83 +/- 0.08 +/- 0.01, C(B-0 -> psi(2S) K-S(0)) = -0.05 +/- 0.10 +/- 0.01, S(B-0 -> psi(2S) K-S(0)) = 0.84 +/- 0.10 +/- 0.01, where C describes CP violation in the direct decay, and S describes CP violation in the interference between the amplitudes for the direct decay and for the decay after B-0-(B) over bar (0) oscillation. The first uncertainties are statistical and the second are systematic. The two sets of results are compatible with the previous LHCb measurement using B-0 -> J/psi K-S(0) decays, where the J/psi meson was reconstructed from two muons. The averages of all three sets of LHCb results are C(B-0 -> [c (c) over bar] K-S(0)) = -0.017 +/- 0.029, S(B-0 -> [c (c) over bar] K-S(0)) = 0.760 +/- 0.034, under the assumption that higher-order contributions to the decay amplitudes are negligible. The uncertainties include statistical and systematic contributions.
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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-+/- production cross-section in pp collisions at root s=7 and 13 TeV. J. High Energy Phys., 12(12), 026–25pp.
Abstract: The production of B +/- mesons is studied in pp collisions at centre-of-mass energies of 7 and 13 TeV, using B-+/- -> J/psi K-+/- decays and data samples corresponding to 1.0 fb(-1) and 0.3 fb(-1), respectively. The production cross-sections summed over both charges and integrated over the transverse momentum range 0 < pT < 40 GeV/c and the rapidity range 2.0 < y < 4.5 are measured to be sigma-(pp -> B-+/- X, root s = 7 TeV) = 43.0 +/- 0.2 +/- 2.5 +/- 1.7 μb, sigma(pp -> B-+/- X, root s = 13 TeV) = 86.6 +/- 0.5 +/- 5.4 +/- 3.4 μb, where the first uncertainties are statistical, the second are systematic, and the third are due to the limited knowledge of the B-+/- -> J/psi K-+/- branching fraction. The ratio of the cross-section at 13 TeV to that at 7 TeV is determined to be 2.02 +/- 0.02 (stat) +/- 0.12 (syst). Differential cross-sections are also reported as functions of pi, and y. All results are in agreement with theoretical calculations based on the state-of-art fixed next-to-leading order quantum chromodynamics.
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