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Escrihuela, F. J., Forero, D. V., Miranda, O. G., Tortola, M., & Valle, J. W. F. (2015). On the description of nonunitary neutrino mixing. Phys. Rev. D, 92(5), 053009–16pp.
Abstract: Neutrino oscillations are well established and the relevant parameters determined with good precision, except for the CP phase, in terms of a unitary lepton mixing matrix. Seesaw extensions of the Standard Model predict unitarity deviations due to the admixture of heavy isosinglet neutrinos. We provide a complete description of the unitarity and universality deviations in the light-neutrino sector. Neutrino oscillation experiments involving electron or muon neutrinos and antineutrinos are fully described in terms of just three new real parameters and a new CP phase, in addition to the ones describing oscillations with unitary mixing. Using this formalism we describe the implications of nonunitarity for neutrino oscillations and summarize the model-independent constraints on heavy-neutrino couplings that arise from current experiments.
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Bernardoni, F., Blossier, B., Bulava, J., Della Morte, M., Fritzsch, P., Garron, N., et al. (2015). B-meson spectroscopy in HQET at order 1/m. Phys. Rev. D, 92(5), 054509–25pp.
Abstract: We present a study of the B spectrum performed in the framework of heavy quark effective theory expanded to next-to-leading order in 1/m(b) and nonperturbative in the strong coupling. Our analyses have been performed on N-f = 2 lattice gauge field ensembles corresponding to three different lattice spacings and a wide range of pion masses. We obtain the B-s-meson mass and hyperfine splittings of the B-and B-s-mesons that are in good agreement with the experimental values and examine the mass difference m(Bs) – m(B) as a further cross-check of our previous estimate of the b-quark mass. We also report on the mass splitting between the first excited state and the ground state in the B and B-s systems.
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Sekihara, T., & Oset, E. (2015). Investigating the nature of light scalar mesons with semileptonic decays of D mesons. Phys. Rev. D, 92(5), 054038–17pp.
Abstract: We study the semileptonic decays of D-s(+), D+, and D-0 mesons into the light scalar mesons [f(0)(500), K-0(*)(800), f(0)(980), and a(0)(980)] and the light vector mesons [rho(770), omega(782), K-*(892), and phi(1020)]. With the help of a chiral unitarity approach in coupled channels, we compute the branching fractions for scalar meson processes of the semileptonic D decays in a simple way. Using current known values of the branching fractions, we make predictions for the branching fractions of the semileptonic decay modes with other scalar and vector mesons. Furthermore, we calculate the pi(+)pi(-), pi eta, pi K, and K+K- invariant mass distributions in the semileptonic decays of D mesons, which will help us clarify the nature of the light scalar mesons.
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ATLAS Collaboration(Aad, G. et al), Alvarez Piqueras, D., Cabrera Urban, S., Castillo Gimenez, V., Costa, M. J., Fernandez Martinez, P., et al. (2015). Search for photonic signatures of gauge-mediated supersymmetry in 8 TeV pp collisions with the ATLAS detector. Phys. Rev. D, 92(7), 072001–35pp.
Abstract: A search is presented for photonic signatures motivated by generalized models of gauge-mediated supersymmetry breaking. This search makes use of 20.3 fb(-1) of proton-proton collision data at root s = 8 TeV recorded by the ATLAS detector at the LHC, and explores models dominated by both strong and electroweak production of supersymmetric partner states. Four experimental signatures incorporating an isolated photon and significant missing transverse momentum are explored. These signatures include events with an additional photon, lepton, b-quark jet, or jet activity not associated with any specific underlying quark flavor. No significant excess of events is observed above the Standard Model prediction and model-dependent 95% confidence-level exclusion limits are set.
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LHCb Collaboration(Aaij, R. et al), Martinez-Vidal, F., Oyanguren, A., Ruiz Valls, P., & Sanchez Mayordomo, C. (2015). Measurement of the branching fraction ratio B(B-c(+) -> psi(2S)pi(+))/B(B-c(+) -> J/psi pi(+)). Phys. Rev. D, 92(7), 072007–10pp.
Abstract: Using pp collision data collected by LHCb at center-of-mass energies root s = 7 TeV and 8 TeV, corresponding to an integrated luminosity of 3 fb(-1), the ratio of the branching fraction of the B-c(+) -> psi(2S)pi(+) decay relative to that of the B-c(+) -> J/psi pi(+) decay is measured to be 0.268 +/- 0.032(stat) +/- 0.007(syst) +/- 0.006(BF). The first uncertainty is statistical, the second is systematic, and the third is due to the uncertainties on the branching fractions of the J/psi -> mu(+)mu(-) and psi(2S) -> mu(+)mu(-) decays. This measurement is consistent with the previous LHCb result, and the statistical uncertainty is halved.
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