ATF Collaboration(Bambade, P. e al), Alabau Pons, M., & Faus-Golfe, A. (2010). Present status and first results of the final focus beam line at the KEK Accelerator Test Facility. Phys. Rev. Spec. Top.-Accel. Beams, 13(4), 042801–10pp.
Abstract: ATF2 is a final-focus test beam line which aims to focus the low emittance beam from the ATF damping ring to a vertical size of about 37 nm and to demonstrate nanometer level beam stability. Several advanced beam diagnostics and feedback tools are used. In December 2008, construction and installation were completed and beam commissioning started, supported by an international team of Asian, European, and U. S. scientists. The present status and first results are described.
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BABAR Collaboration(Aubert, B. et al), Azzolini, V., Lopez-March, N., Martinez-Vidal, F., Milanes, D. A., & Oyanguren, A. (2010). Observation of the chi(c2)(2P) meson in the reaction gamma gamma -> D(D)over-bar at BABAR. Phys. Rev. D, 81(9), 092003–16pp.
Abstract: A search for the Z(3930) resonance in gamma gamma production of the D (D) over bar system has been performed using a data sample corresponding to an integrated luminosity of 384 fb(-1) recorded by the BABAR experiment at the PEP-II asymmetric-energy electron-positron collider. The D (D) over bar invariant mass distribution shows clear evidence of the Z(3930) state with a significance of 5.8 sigma. We determine mass and width values of (3926.7 +/- 2.7 +/- 1.1) MeV/c(2) and (21.3 +/- 6.8 +/- 3.6) MeV, respectively. A decay angular analysis provides evidence that the Z(3930) is a tensor state with positive parity and C parity (J(PC) = 2(++)); therefore we identify the Z(3930) state as the chi(c2)(2P) meson. The value of the partial width Gamma(gamma gamma) x B(Z(3930) -> D (D) over bar) is found to be (0.24 +/- 0.05 +/- 0.04) keV.
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Gamermann, D., Garcia-Recio, C., Nieves, J., Salcedo, L. L., & Tolos, L. (2010). Exotic dynamically generated baryons with negative charm quantum number. Phys. Rev. D, 81(9), 094016–11pp.
Abstract: Following a model based on the SU(8) symmetry that treats heavy pseudoscalars and heavy vector mesons on an equal footing, as required by heavy quark symmetry, we study the interaction of baryons and mesons in coupled channels within an unitary approach that generates dynamically poles in the scattering T-matrix. We concentrate in the exotic channels with negative charm quantum number for which there is the experimental claim of one state.
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Bozzi, G., Campanario, F., Hankele, V., & Zeppenfeld, D. (2010). Next-to-leading order QCD corrections to W+W-gamma and ZZ gamma production with leptonic decays. Phys. Rev. D, 81(9), 094030–7pp.
Abstract: The computation of the O(alpha(s)) QCD corrections to the cross sections for W+W-gamma and ZZ gamma production in hadronic collisions is presented. We consider the case of a real photon in the final state, but include full leptonic decays of the W and Z bosons. Numerical results for the LHC and the Tevatron are obtained through a fully flexible parton level Monte Carlo program based on the structure of the VBFNLO program, allowing an easy implementation of arbitrary cuts and distributions. We show the dependence on scale variations of the integrated cross sections and provide evidence that next-to-leading order (NLO) QCD corrections strongly modify the LO predictions for observables at the LHC both in magnitude and in shape.
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Fileviez Perez, P., Iminniyaz, H., Rodrigo, G., & Spinner, S. (2010). Gauge mediated supersymmetry breaking via seesaw mechanisms. Phys. Rev. D, 81(9), 095013–12pp.
Abstract: We present a simple scenario for gauge mediated supersymmetry breaking (GMSB) where the messengers are also the fields that generate neutrino masses. We show that the simplest such scenario corresponds to the case where neutrino masses are generated through the type I and type III seesaw mechanisms. The entire supersymmetric spectrum and Higgs masses are calculable from only four input parameters. Since the electroweak symmetry is broken through a doubly radiative mechanism, meaning a nearly zero B term at the messenger scale which runs down to acceptable values, one obtains quite a constrained spectrum for the supersymmetric particles whose properties we describe. We refer to this mechanism as "nu GMSB.''
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Modamio, V., Jungclaus, A., Algora, A., Bazzacco, D., Escrig, D., Fraile, L. M., et al. (2010). New high-spin isomer and quasiparticle-vibration coupling in Ir-187. Phys. Rev. C, 81(5), 054304–13pp.
Abstract: The high-spin structure of the Z = 77 nucleus Ir-187 has been studied using the fusion-evaporation reaction W-186(Li-7, (6)n) at a beam energy of 59 MeV. The excitation scheme of this nucleus has been extended by more than 110 new states, including extensions of all previously established rotational bands. The band crossing region of the h(9/2) negative-parity yrast band has been revised and new intrinsic high-K states have been identified. In particular, a 29/2(-) isomeric state [T-1/2 = 1.8(5)mu s] at an excitation energy of 2487 keV has been observed for the first time, and on top of it, a rich level scheme reaching up to spin (59/2(-)) and excitation energies around 7 MeV has been established.
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TAPS Collaboration, Piasecki, K., Matulewicz, T., Yahlali, N., Delagrange, H., Diaz, J., et al. (2010). Emission patterns of neutral pions in 40A MeV Ta plus Au reactions. Phys. Rev. C, 81(5), 054912–7pp.
Abstract: Differential cross sections of neutral pions emitted in Ta-181+Au-197 collisions at a beam energy of 39.5A Me V have been measured with the two-arm photon spectrometer (TAPS). The kinetic energy and transverse momentum spectra of neutral pions cannot be properly described in the framework of the thermal model, nor when the reabsorption of pions is accounted for in a phenomenological model. However, high energy and high momentum tails of the pion spectra can be well fitted through thermal distributions with unexpectedly soft temperature parameters below 10 MeV.
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Martinez Torres, A., & Oset, E. (2010). The gamma d -> K(+)K(-)np reaction and an alternative explanation for the “Theta(+)(1540) pentaquark” peak. Phys. Rev. C, 81(5), 055202–16pp.
Abstract: We present a calculation of the gamma d -> K(+)K(-)np reaction with the aim of seeing whether the experimental peak observed in the K(+)n invariant mass around 1526 MeV, from where evidence for the existence of the Theta(+) has been claimed, can be obtained without this resonance as a consequence of the particular dynamics of the process and the cuts applied in the experimental setup. We find that a combination of facts leads indeed to a peak around 1530 MeV for the invariant mass of K(+)n without the need to invoke any new resonance around this energy. This, together with statistical fluctuations that we prove to be large with the statistics of the experiment, is likely to produce the narrower peak observed there.
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n_TOF Collaboration(Tagliente, G. et al.), Domingo-Pardo, C., & Tain, J. L. (2010). The Zr-92(n,gamma) reaction and its implications for stellar nucleosynthesis. Phys. Rev. C, 81(5), 055801–9pp.
Abstract: Because the relatively small neutron capture cross sections of the zirconium isotopes are difficult to measure, the results of previous measurements are often not adequate for a number of problems in astrophysics and nuclear technology. Therefore, the Zr-92(n,gamma) cross section has been remeasured at the CERN n_TOF facility, providing a set of improved parameters for 44 resonances in the neutron energy range up to 40 keV. With this information the cross-section uncertainties in the keV region could be reduced to 5% as required for s-process nucleosynthesis studies and technological applications.
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Perez, A. (2010). Information encoding of a qubit into a multilevel environment. Phys. Rev. A, 81(5), 052326–6pp.
Abstract: I consider the interaction of a small quantum system (a qubit) with a structured environment consisting of many levels. The qubit will experience a decoherence process, which implies that part of its initial information will be encoded into correlations between system and environment. I investigate how this information is distributed on a given subset of levels as a function of its size, using the mutual information between both entities, in the spirit of the partial-information plots studied by Zurek and co-workers. In this case we can observe some differences, which arise from the fact that I am partitioning just one quantum system and not a collection of them. However, some similar features, like redundancy (in the sense that a given amount of information is shared by many subsets), which increases with the size of the environment, are also found here.
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