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Albertus, C., Hernandez, E., & Nieves, J. (2012). Exclusive c -> s, d semileptonic decays of ground-state spin-1/2 and spin-3/2 doubly heavy cb baryons. Phys. Rev. D, 85(9), 094035–21pp.
Abstract: We evaluate exclusive semileptonic decays of ground-state spin-1/2 and spin-3/2 doubly heavy cb baryons driven by a c --> s, d transition at the quark level. We check our results for the form factors against heavy quark spin symmetry constraints obtained in the limit of very large heavy quark masses and near zero recoil. Based on those constraints we make model-independent, though approximate, predictions for ratios of decay widths.
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Bertolini, S., Di Luzio, L., & Malinsky, M. (2012). Seesaw scale in the minimal renormalizable SO(10) grand unification. Phys. Rev. D, 85(9), 095014–22pp.
Abstract: Simple SO(10) Higgs models with the adjoint representation triggering the grand unified symmetry breaking, discarded long ago due to inherent tree-level tachyonic instabilities in the physically interesting scenarios, have been recently brought back to life by quantum effects. In this work we focus on the variant with 45(H) circle plus 126(H) in the Higgs sector and show that there are several regions in the parameter space of this model that can support stable unifying configurations with the B – L-breaking scale as high as 10(14) GeV, well above the previous generic estimates based on the minimal survival hypothesis. This admits for a renormalizable implementation of the canonical seesaw and makes the simplest potentially realistic scenario of this kind a good candidate for a minimal SO(10) grand unification. Last, but not least, this setting is likely to be extensively testable at future large-volume facilities such as Hyper-Kamiokande.
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BABAR Collaboration(Lees, J. P. et al), Lopez-March, N., Martinez-Vidal, F., & Oyanguren, A. (2012). Search for the decay D-0 -> gamma gamma and measurement of the branching fraction for D-0 -> pi(0)pi(0). Phys. Rev. D, 85(9), 091107–8pp.
Abstract: We search for the rare decay of the D-0 meson to two photons, D-0 -> gamma gamma, and present a measurement of the branching fraction for a D-0 meson decaying to two neutral pions, B(D-0 -> pi(0)pi(0)). The data sample analyzed corresponds to an integrated luminosity of 470.5 fb(-1) collected by the BABAR detector at the PEP-II asymmetric-energy e(+)e(-) collider at SLAC. We place an upper limit on the branching fraction, B(D-0 -> gamma gamma) < 2.2 x 10(-6), at 90% confidence level. This limit improves on the existing limit by an order of magnitude. We also find B(D-0 -> pi(0)pi(0)) = (8.4 +/- 0.1 +/- 0.4 +/- 0.3 +/-) x 10(-4).
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Aguilar-Saavedra, J. A., Deppisch, F., Kittel, O., & Valle, J. W. F. (2012). Flavor in heavy neutrino searches at the LHC. Phys. Rev. D, 85(9), 091301–4pp.
Abstract: Heavy neutrinos at the TeV scale have been searched for at the LHC in the context of left-right models, under the assumption that they couple to the electron, the muon, or both. We show that current searches are also sensitive to heavy neutrinos coupling predominantly to the tau lepton, and present limits can significantly constrain the parameter space of general flavor mixing.
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ATLAS Collaboration(Aad, G. et al), Amoros, G., Cabrera Urban, S., Castillo Gimenez, V., Costa, M. J., Ferrer, A., et al. (2012). Measurement of the production cross section of an isolated photon associated with jets in proton-proton collisions at root s=7 TeV with the ATLAS detector. Phys. Rev. D, 85(9), 092014–30pp.
Abstract: A measurement of the cross section for the production of an isolated photon in association with jets in proton-proton collisions at a center-of-mass energy root s = 7 TeV is presented. Photons are reconstructed in the pseudorapidity range vertical bar eta(gamma)vertical bar < 1.37 and with a transverse energy E-T(gamma) > 25 GeV. Jets are reconstructed in the rapidity range vertical bar y(jet)vertical bar < 4.4 and with a transverse momentum p(T)(jet) > 20 GeV. The differential cross section d sigma/dE(T)(gamma) is measured, as a function of the photon transverse energy, for three different rapidity ranges of the leading-p(T) jet: vertical bar y(jet)vertical bar < 1.2, 1.2 <= vertical bar y(jet)vertical bar < 2.8 and 2.8 <= vertical bar y(jet)vertical bar < 4.4. For each rapidity configuration the same-sign (eta(gamma)y(jet) >= 0) and opposite-sign (eta(gamma) y(jet) < 0) cases are studied separately. The results are based on an integrated luminosity of 37 pb(-1), collected with the ATLAS detector at the LHC. Next-to-leading order perturbative QCD calculations are found to be in fair agreement with the data, except for E-T(gamma) <= 45 GeV, where the theoretical predictions overestimate the measured cross sections.
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