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Liang, W. H., & Oset, E. (2014). B-0 and B-s(0) decays into J/psi f(0)(980) and J/psi f(0)(500) and the nature of the scalar resonances. Phys. Lett. B, 737, 70–74.
Abstract: We describe the B-0 and B-s(0) decays into J/psi f(0)(500) and J/psi f(0)(980) by taking into account the dominant process for the weak decay of B-0 and B-s(0) into J/psi and a q (q) over bar component. After hadronization of this q (q) over bar component into pairs of pseudoscalar mesons we obtain certain weights for the meson-meson components and allow them to interact among themselves. The final state interaction of the meson-meson components, described in terms of chiral unitary theory, gives rise to the f(0)(980) and f(0)(500) resonances and we can obtain the pi(+)pi(-) invariant mass distributions after the decay of the resonances, which allows us to compare directly to the experiments. We obtain ratios of J/psi f(0)(980) and J/psi f(0)( 500) for each of the B decays in quantitative agreement with experiment, with the f(0)(980) clearly dominant in the B-s(0) decay and the f(0)(500) in the B-0 decay.
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Celis, A., Fuentes-Martin, J., & Serodio, H. (2014). Effective aligned 2HDM with a DFSZ-like invisible axion. Phys. Lett. B, 737, 185–190.
Abstract: We discuss the possibility of having a non-minimal scalar sector at the weak scale within the framework of invisible axion models. To frame our discussion we consider an extension of the Dine-Fischler-Srednicki-Zhitnitsky invisible axion model with two additional Higgs doublets blind under the Peccei-Quinn symmetry. Due to mixing effects among the scalar fields, it is possible to obtain a rich scalar sector at the weak scale in certain decoupling limits of the theory. In particular, this framework provides an ultraviolet completion of the so-called aligned two-Higgs-doublet model and solves the strong CP problem. The axion properties and the smallness of active neutrino masses are also discussed.
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ATLAS Collaboration(Aad, G. et al), Cabrera Urban, S., Castillo Gimenez, V., Costa, M. J., Fassi, F., Ferrer, A., et al. (2014). Search for WZ resonances in the fully leptonic channel using pp collisions at root s=8 TeV with the ATLAS detector. Phys. Lett. B, 737, 223–243.
Abstract: A search for resonant WZ production in the l nu l'l' (l, l' = e, mu) decay channel using 20.3 fb(-1) of root s = 8 TeV pp collision data collected by the ATLAS experiment at LHC is presented. No significant deviation from the Standard Model prediction is observed and upper limits on the production cross sections of WZ resonances from an extended gauge model W' and from a simplified model of heavy vector triplets are derived. A corresponding observed (expected) lower mass limit of 1.52 (1.49) TeV is derived for the W' at the 95% confidence level. (C) 2014 CERN for the benefit of the ATLAS Collaboration.
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Brown, J. M. C., Dimmock, M. R., Gillam, J. E., & Paganin, D. M. (2014). A low energy bound atomic electron Compton scattering model for Geant4. Nucl. Instrum. Methods Phys. Res. B, 338, 77–88.
Abstract: A two-body fully relativistic three-dimensional scattering framework has been utilised to develop an alternative Compton scattering computational model to those adapted from Ribberfors' work for Monte Carlo modelling of Compton scattering. Using a theoretical foundation that ensures the conservation of energy and momentum in the relativistic impulse approximation, this new model, the Monash University Compton scattering model, develops energy and directional algorithms for both the scattered photon and ejected Compton electron from first principles. The Monash University Compton scattering model was developed to address the limitation of the Compton electron directionality algorithms of other computational models adapted from Ribberfors' work. Here the development of the Monash University Compton scattering model, including its implementation in a Geant4 low energy electromagnetic physics class, G4LowEPComptonModel, is outlined. Assessment of the performance of G4LowEPComptonModel was undertaken in two steps: (1) comparison with respect to the two standard Compton scattering classes of Geant4 version 9.5, G4LivermoreComptonModel and G4PenelopeComptonModel, and (2) experimental comparison with respect to Compton electron kinetic energy spectra obtained from the Compton scattering of 662 key photons off the K-shell of gold. Both studies illustrate that the Monash University Compton scattering model, and in turn G4LowEPComptonModel, is a viable replacement for the majority of computational models that have been adapted from Ribberfors' work. It was also shown that the Monash University Compton scattering model is able to reproduce the Compton scattering triply differential cross-section Compton electron kinetic energy spectra of 662 keV photons K-shell scattering off of gold to within experimental uncertainty.
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Scandale, W. et al, & Lari, L. (2014). Deflection of high energy protons by multiple volume reflections in a modified multi-strip silicon deflector. Nucl. Instrum. Methods Phys. Res. B, 338, 108–111.
Abstract: The effect of multiple volume reflections in one crystal was observed in each of several bent silicon strips for 400 GeV/c protons. This considerably increased the particle deflections. Some particles were also deflected due to channeling in one of the subsequent strips. As a result, the incident beam was strongly spread because of opposite directions of the deflections. A modified multi-strip deflector produced by periodic grooves on the surface of a thick silicon plate was used for these measurements. This technique provides perfect mutual alignment between crystal strips. Such multi-strip deflector may be effective for collider beam halo collimation and a study is planned at the CERN SPS circulating beam.
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