Armillis, R., Lazarides, G., & Pallis, C. (2014). Inflation, leptogenesis, and Yukawa quasiunification within a supersymmetric left-right model. Phys. Rev. D, 89(6), 065032–22pp.
Abstract: A simple extension of the minimal left-right symmetric supersymmetric grand unified theory model is constructed by adding two pairs of superfields. This naturally violates the partial Yukawa unification predicted by the minimal model. After including supergravity corrections, we find that this extended model naturally supports hilltop F-term hybrid inflation along its trivial inflationary path with only a very mild tuning of the initial conditions. With a convenient choice of signs of the terms in the Kahler potential, we can reconcile the inflationary scale with the supersymmetric grand unified theory scale. All the current data on the inflationary observables are readily reproduced. Inflation is followed by nonthermal leptogenesis via the decay of the right-handed neutrinos emerging from the decay of the inflaton, and any possible washout of the lepton asymmetry is avoided thanks to the violation of partial Yukawa unification. The extra superfields also assist us in reducing the reheat temperature so as to satisfy the gravitino constraint. The observed baryon asymmetry of the universe is naturally reproduced consistently with the neutrino oscillation parameters.
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LHCb Collaboration(Aaij, R. et al), Martinez-Vidal, F., Oyanguren, A., Ruiz Valls, P., & Sanchez Mayordomo, C. (2014). Study of chi(b) meson production in pp collisions at root s=7 and 8 TeV and observation of the decay chi(b) (3P) -> gamma(3S)gamma. Eur. Phys. J. C, 74(10), 3092–13pp.
Abstract: A study of chi(b) meson production at LHCb is performed on proton-proton collision data, corresponding to 3.0 fb(-1) of integrated luminosity collected at centre-of-mass energies root s = 7 and 8 TeV. The fraction of gamma(nS) mesons originating from chi(b) decays is measured as a function of the gamma transverse momentum in the rapidity range 2.0 < y(gamma) < 4.5. The radiative transition of the chi(b) (3P) meson to gamma(3S) is observed for the first time. The chi(b)1 (3P) mass is determined to be m chi(b1) (3P) = 10 511.3 +/- 1.7 +/- 2.5MeV/c(2), where the first uncertainty is statistical and the second is systematic.
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NEXT Collaboration(Alvarez, V. et al), Carcel, S., Cervera-Villanueva, A., Diaz, J., Ferrario, P., Gil, A., et al. (2014). Description and commissioning of NEXT-MM prototype: first results from operation in a Xenon-Trimethylamine gas mixture. J. Instrum., 9, P03010–22pp.
Abstract: A technical description of NEXT-MM and its commissioning and first performance is reported. Having an active volume of similar to 35 cm drift x 28 cm diameter, it constitutes the largest Micromegas-read TPC operated in Xenon ever constructed, made by a sectorial arrangement of the 4 largest single wafers manufactured with the Microbulk technique to date. It is equipped with a suitably pixelized readout and with a sufficiently large sensitive volume (similar to 23 l) so as to contain long (similar to 20 cm) electron tracks. First results obtained at 1 bar for Xenon and Trymethylamine (Xe-(2%) TMA) mixture are presented. The TPC can accurately reconstruct extended background tracks. An encouraging full-width half-maximum of 11.6% was obtained for similar to 29 keV gammas without resorting to any data post-processing.
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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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Rebel, B., Hall, C., Bernard, E., Faham, C. H., Ito, T. M., Lundberg, B., et al. (2014). High voltage in noble liquids for high energy physics. J. Instrum., 9, T08004–57pp.
Abstract: A workshop was held at Fermilab November 8-9, 2013 to discuss the challenges of using high voltage in noble liquids. The participants spanned the fields of neutrino, dark matter, and electric dipole moment physics. All presentations at the workshop were made in plenary sessions. This document summarizes the experiences and lessons learned from experiments in these fields at developing high voltage systems in noble liquids.
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