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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n_TOF Collaboration(Gunsing, F. et al), Domingo-Pardo, C., & Tain, J. L. (2012). Measurement of resolved resonances of Th-232(n, gamma) at the n_TOF facility at CERN. Phys. Rev. C, 85(6), 064601–17pp.
Abstract: The yield of the neutron capture reaction Th-232(n, gamma) has been measured at the neutron time-of-flight facility n_TOF at CERN in the energy range from 1 eV to 1 MeV. The reduction of the acquired data to the capture yield for resolved resonances from 1 eV to 4 keV is described and compared to a recent evaluated data set. The resonance parameters were used to assign an orbital momentum to each resonance. A missing level estimator was used to extract the s-wave level spacing of D-0 = 17.2 +/- 0.9 eV.
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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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Recchia, F. et al, & Gadea, A. (2012). Spectroscopy of odd-mass cobalt isotopes toward the N=40 subshell closure and shell-model description of spherical and deformed states. Phys. Rev. C, 85(6), 064305–10pp.
Abstract: The neutron-rich cobalt isotopes up to A = 67 have been studied through multinucleon transfer reactions by bombarding a U-238 target with a 460-MeV Zn-70 beam. Unambiguous identification of prompt gamma rays belonging to each nucleus has been achieved using coincidence relationships with the ions detected in a high-acceptance magnetic spectrometer. The new data are discussed in terms of the systematics of the cobalt isotopes and interpreted with large-scale shell-model calculations in the fpgd model space. In particular, very different shapes can be described in Co-67, at the edge of the island of inversion at N = 40, where a low-lying highly deformed band coexists with a spherical structure.
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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). Search for Pair Production of a Heavy Up-Type Quark Decaying to a W Boson and a b Quark in the lepton plus jets Channel with the ATLAS Detector. Phys. Rev. Lett., 108(26), 261802–18pp.
Abstract: A search is presented for production of a heavy up-type quark (t') together with its antiparticle, assuming subsequent decay to a W boson and a b quark, t'(t) over bar' -> W(+)bW(-)(b) over bar. The search is based on 1.04 fb(-1) of proton-proton collisions at root s = 7 TeV collected by the ATLAS detector at the CERN Large Hadron Collider. Data are analyzed in the lepton + jets final state, characterized by a high transverse momentum isolated electron or muon, high missing transverse momentum, and at least three jets. No significant excess of events above the background expectation is observed. A 95% C.L. lower limit of 404 GeV is set for the mass of the t' quark.
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BABAR Collaboration(Lees, J. P. et al), Martinez-Vidal, F., & Oyanguren, A. (2012). Study of CP violation in Dalitz-plot analyses of B-0 -> K+ K- K-s(0), B+ -> K+ K- K+, and B+ -> (KsKsK+)-K-0-K-0. Phys. Rev. D, 85(11), 112010–31pp.
Abstract: We perform amplitude analyses of the decays B-0 -> K+ K- K-s(0), B+ -> K+ K- K+, and B+ -> K-s(0) K-s(0) K+, and measure CP-violating parameters and partial branching fractions. The results are based on a data sample of approximately 470 x 10(6) B (B) over bar decays, collected with the BABAR detector at the PEP-II asymmetric-energy B factory at the SLAC National Accelerator Laboratory. For B+ -> K+ K- K+, we find a direct CP asymmetry in B+ -> phi(1020)K+ of A(CP) = (12.8 +/- 4.4 +/- 1.3)%, which differs from zero by 2.8 sigma. For B-0 -> K+ K- K-s(0), we measure the CP-violating phase ss(eff)(phi(1020)K-s(0)) = (21 +/- 6 +/- 2)degrees. For B+ -> K-s(0) K-s(0) K+, we measure an overall direct CP asymmetry of A(CP) = (4(-5)(+4) +/- 2)%. We also perform an angular-moment analysis of the three channels and determine that the f(X()1500) state can be described well by the sum of the resonances f(0)(1500), f(2)'(1525), and f(0)(1710).
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Bottoni, S. et al, & Gadea, A. (2012). Reaction dynamics and nuclear structure of moderately neutron-rich Ne isotopes by heavy-ion reactions. Phys. Rev. C, 85(6), 064621–7pp.
Abstract: The heavy-ion reaction Ne-22+Pb-208 at 128 MeV beam energy has been studied using the PRISMA-CLARA experimental setup at Legnaro National Laboratories. Elastic, inelastic, and one-nucleon transfer differential cross sections are measured and global agreement is obtained with semiclassical and distorted-wave Born approximation (DWBA) calculations. In particular, the angular distribution of the 2(+) state of Ne-22 is analyzed by DWBA and a similar calculation is performed for the unstable Ne-24 nucleus, using existing data from the reaction Ne-24+Pb-208 at 182 MeV (measured at SPIRAL with the VAMOS-EXOGAM setup). In both cases the DWBA model gives a good reproduction of the experiment, pointing to a strong reduction of the beta(C)(2) charge deformation parameter in Ne-24. This follows the trend predicted for the evolution of the quadrupole deformation along the Ne isotopic chain.
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BABAR Collaboration(Lees, J. P. et al), Martinez-Vidal, F., & Oyanguren, A. (2012). Initial-state radiation measurement of the e(+)e(-) -> pi(+)pi(-)pi(+)pi(-) cross section. Phys. Rev. D, 85(11), 112009–17pp.
Abstract: We study the process e(+)e(-) -> pi(+)pi(-)pi(+)pi(-)gamma, with a photon emitted from the initial-state electron or positron, using 454.3 fb(-1) of data collected with the BABAR detector at SLAC, corresponding to approximately 260 000 signal events. We use these data to extract the nonradiative sigma(e(+)e(-) -> pi(+)pi(-)pi(+)pi(-)) cross section in the energy range from 0.6 to 4.5 GeV. The total uncertainty of the cross section measurement in the peak region is less than 3%, higher in precision than the corresponding results obtained from energy scan data.
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