LHCb Collaboration(Aaij, R. et al), Martinez-Vidal, F., Oyanguren, A., Ruiz Valls, P., & Sanchez Mayordomo, C. (2014). Measurement of CP violation parameters in B-0 -> DK*(0) decays. Phys. Rev. D, 90(11), 112002–14pp.
Abstract: An analysis of B-0 --> DK*(0) decays is presented, where D represents an admixture of D-0 and (D) over bar (0) mesons reconstructed in four separate final states: K-pi(+), pi K--(+), K+K- and pi(+)pi(-). The data sample corresponds to 3.0 fb(-1) of proton-proton collision, collected by the LHCb experiment. Measurements of several observables are performed, including CP asymmetries. The most precise determination is presented of r(B)(DK*(0)), the magnitude of the ratio of the amplitudes of the decay B-0 --> DK+pi(-) with a b --> u or a b --> c transition, in a K pi mass region of +/- 50 MeV/c(2) around the K*(892) mass and for an absolute value of the cosine of the K*(0) helicity angle larger than 0.4.
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ATLAS Collaboration(Aad, G. et al), Cabrera Urban, S., Castillo Gimenez, V., Costa, M. J., Ferrer, A., Fiorini, L., et al. (2014). Search for nonpointing and delayed photons in the diphoton and missing transverse momentum final state in 8 TeV pp collisions at the LHC using the ATLAS detector. Phys. Rev. D, 90(11), 112005–29pp.
Abstract: A search has been performed, using the full 20.3 fb(-1) data sample of 8 TeV proton-proton collisions collected in 2012 with the ATLAS detector at the LHC, for photons originating from a displaced vertex due to the decay of a neutral long-lived particle into a photon and an invisible particle. The analysis investigates the diphoton plus missing transverse momentum final state, and is therefore most sensitive to pair production of long-lived particles. The analysis technique exploits the capabilities of the ATLAS electromagnetic calorimeter to make precise measurements of the flight direction, as well as the time of flight, of photons. No excess is observed over the Standard Model predictions for background. Exclusion limits are set within the context of gauge mediated supersymmetry breaking models, with the lightest neutralino being the next-to-lightest supersymmetric particle and decaying into a photon and gravitino with a lifetime in the range from 250 ps to about 100 ns.
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ATLAS Collaboration(Aad, G. et al), Cabrera Urban, S., Castillo Gimenez, V., Costa, M. J., Ferrer, A., Fiorini, L., et al. (2014). Comprehensive measurements of t-channel single top-quark production cross sections at root S=7 TeV with the ATLAS detector. Phys. Rev. D, 90(11), 112006–45pp.
Abstract: This article presents measurements of the t-channel single top-quark ((t) over bart) and top-antiquark ( t) total production cross sections sdtq and sd tq, their ratio Rt sdtq= sd tq, and a measurement of the inclusive production cross section sdtq tq in proton-proton collisions at ffiffiffi ps = 7 TeV at the LHC. Differential cross sections for the tq and tq processes are measured as a function of the transverse momentum and the absolute value of the rapidity of t and t, respectively. The analyzed data set was recorded with the ATLAS detector and corresponds to an integrated luminosity of 4.59 fb-1. Selected events contain one charged lepton, large missing transverse momentum, and two or three jets. The cross sections are measured by performing a binned maximum-likelihood fit to the output distributions of neural networks. The resulting measurements are sdtq 46 = 1dstat = 6dsyst pb, sd tq = 23 +/- 1dstat = 3dsyst pb, Rt = 2.04 0.13dstat +/-=0.12dsyst, and sdtq tq = 68 +/-= 2dstat = 8dsyst pb, consistent with the Standard Model expectation. The uncertainty on the measured cross sections is dominated by systematic uncertainties, while the uncertainty on Rt is mainly statistical. Using the ratio of sdtq tq_ to its theoretical prediction, and assuming that the top-quark-related CKM matrix elements obey the relation jVtbj = jVtsj; jVtdj, we determine jVtbj = 1.02 = 0.07.
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LHCb Collaboration(Aaij, R. et al), Martinez-Vidal, F., Oyanguren, A., Ruiz Valls, P., & Sanchez Mayordomo, C. (2014). Measurements of CP violation in the three-body phase space of charmless B-+/- decays. Phys. Rev. D, 90(11), 112004–17pp.
Abstract: The charmless three- body decay modes B +/- -> K +/-pi(-)pi(-), B-+/- -> K-+/- (KK-)-K-+/-, B-+/- pi(-) K-K- and B-+/-pi(-)pi(-) are reconstructed using data, corresponding to an integrated luminosity of 3.0 fb(-1), collected by the LHCb detector. The inclusive CP asymmetries of these modes are measured to be [GRAPHICS] where the first uncertainty is statistical, the second systematic, and the third is due to the CP asymmetry of the B +/- J Psi K-+/- reference mode. The distributions of these asymmetries are also studied as functions of position in the Dalitz plot and suggest contributions from rescattering and resonance interference processes.
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Bayar, M., Liang, W. H., & Oset, E. (2014). B-0 and B-s(0) decays into J/psi plus a scalar or vector meson. Phys. Rev. D, 90(11), 114004–9pp.
Abstract: We extend a recent approach to describe the B-0 and B-s(0) decays into J/psi f(0)(500) and J/psi f(0)(980), relating it to the B-0 and B-s(0) decays into J/psi and a vector meson, phi, rho, K*. In addition, the B-0 and B-s(0) decays into J/psi and kappa(800) are evaluated and compared to the K* vector production. The rates obtained are in agreement with the available experiment while predictions are made for the J/psi plus kappa(800) decay.
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