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LHCb Collaboration(Aaij, R. et al), Oyanguren, A., & Ruiz Valls, P. (2013). Production of J/psi and Y mesons in pp collisions at root s=8 TeV. J. High Energy Phys., 06(6), 064–31pp.
Abstract: The production of J/psi and gamma mesons in pp collisions at root s = 8 TeV is studied with the LHCb detector. The J/psi and gamma mesons are reconstructed in the mu(+)mu(-) decay mode and the signal yields are determined with a fit to the mu(+)mu(-) invariant mass distributions. The analysis is performed in the rapidity range 2.0 < y < 4.5 and transverse momentum range 0 < PT < 14 (15) GeV/c of the J/psi (gamma) mesons. The J/psi and gamma production cross-sections and the fraction of J/psi mesons from b-hadron decays are measured as a function of the meson P-T and y.
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Basso, L., Belyaev, A., Chowdhury, D., Hirsch, M., Khalil, S., Moretti, S., et al. (2013). Proposal for generalised supersymmetry Les Houches Accord for see-saw models and PDG numbering scheme. Comput. Phys. Commun., 184(3), 698–719.
Abstract: The SUSY Les Houches Accord (SLHA) 2 extended the first SLHA to include various generalisations of the Minimal Supersymmetric Standard Model (MSSM) as well as its simplest next-to-minimal version. Here, we propose further extensions to it, to include the most general and well-established see-saw descriptions (types I/II/III, inverse, and linear) in both an effective and a simple gauged extension of the MSSM framework. In addition, we generalise the PDG numbering scheme to reflect the properties of the particles. (c) 2012 Elsevier B.V. All rights reserved.
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Binosi, D., Ibañez, D., & Papavassiliou, J. (2013). QCD effective charge from the three-gluon vertex of the background-field method. Phys. Rev. D, 87(12), 125026–10pp.
Abstract: In this article we study in detail the prospects of determining the infrared finite QCD effective charge from a special kinematic limit of the vertex function corresponding to three background gluons. This particular Green's function satisfies a QED-like Ward identity, relating it to the gluon propagator, with no reference to the ghost sector. Consequently, its longitudinal form factors may be expressed entirely in terms of the corresponding gluon wave function, whose inverse is proportional to the effective charge. After reviewing certain important theoretical properties, we consider a typical lattice quantity involving this vertex, and derive its exact dependence on the various form factors, for arbitrary momenta. We then focus on the particular momentum configuration that eliminates any dependence on the (unknown) transverse form factors, projecting out only the desired quantity. A preliminary numerical analysis indicates that the effective charge is relatively insensitive to the numerical uncertainties that may afflict future simulations of the aforementioned lattice quantity. The numerical difficulties associated with a parallel determination of the dynamical gluon mass are briefly discussed.
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Zamiralov, V. S., Ozpineci, A., & Erkol, G. (2013). QCD sum rules for the coupling constants of vector mesons to octet baryons. Mosc. Univ. Phys. Bull., 68(3), 205–209.
Abstract: The QCD sum rules on the light cone proposed by Wang for the coupling constants of the rho meson are generalized to the vector mesons omega and phi and all octet baryons, the I >-hyperon included. A comparison with other results is given.
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Morisi, S., Nebot, M., Patel, K. M., Peinado, E., & Valle, J. W. F. (2013). Quark-lepton mass relation and CKM mixing in an A(4) extension of the minimal supersymmetric standard model. Phys. Rev. D, 88(3), 036001–8pp.
Abstract: An interesting mass relation between down-type quarks and charged leptons has been recently predicted within a supersymmetric SU(3)(c) circle times SU(2)(L) circle times U(1)(Y) model based on the A(4) flavor symmetry. Here we propose a simple extension which provides an adequate full description of the quark sector. By adding a pair of vectorlike up quarks, we show how the CKM entries V-ub, V-cb, V-td and V-ts arise from deviations of the unitarity. We perform an analysis including the most relevant observables in the quark sector, such as oscillations and rare decays of kaons, B-d and B-s mesons. In the lepton sector, the model predicts an inverted hierarchy for the neutrino masses, leading to a potentially observable rate of neutrinoless double beta decay.
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King, S. F., Morisi, S., Peinado, E., & Valle, J. W. F. (2013). Quark-lepton mass relation in a realistic A(4) extension of the Standard Model. Phys. Lett. B, 724(1-3), 68–72.
Abstract: We propose a realistic A(4) extension of the Standard Model involving a particular quark-lepton mass relation, namely that the ratio of the third family mass to the geometric mean of the first and second family masses are equal for down-type quarks and charged leptons. This relation, which is approximately renormalization group invariant, is usually regarded as arising from the Georgi-Jarlskog relations, but in the present model there is no unification group or supersymmetry. In the neutrino sector we propose a simple modification of the so-called Zee-Wolfenstein mass matrix pattern which allows an acceptable reactor angle along with a deviation of the atmospheric and solar angles from their bi-maximal values. Quark masses, mixing angles and CP violation are well described by a numerical fit.
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NEXT Collaboration(Alvarez, V. et al), Carcel, S., Cervera-Villanueva, A., Diaz, J., Ferrario, P., Gil, A., et al. (2013). Radiopurity control in the NEXT-100 double beta decay experiment: procedures and initial measurements. J. Instrum., 8, T01002–19pp.
Abstract: The “Neutrino Experiment with a Xenon Time-Projection Chamber” (NEXT) is intended to investigate the neutrinoless double beta decay of Xe-136, which requires a severe suppression of potential backgrounds. An extensive screening and material selection process is underway for NEXT since the control of the radiopurity levels of the materials to be used in the experimental set-up is a must for rare event searches. First measurements based on Glow Discharge Mass Spectrometry and gamma-ray spectroscopy using ultra-low background germanium detectors at the Laboratorio Subterraneo de Canfranc (Spain) are described here. Activity results for natural radioactive chains and other common radionuclides are summarized, being the values obtained for some materials like copper and stainless steel very competitive. The implications of these results for the NEXT experiment are also discussed.
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Bottoni, S., Benzoni, G., Leoni, S., Montanari, D., Bracco, A., Vigezzi, E., et al. (2013). Reaction dynamics and gamma spectroscopy of Ne isotoopes by the heavy ion reaction Ne-22+Pb-208. Acta Phys. Pol. B, 44(3), 457–461.
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. Aim of the experiment is the measurement of elastic, inelastic and one nucleon transfer cross sections. The data are presented in parallel with similar results 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). A comparison with angular distributions obtained by semiclassical and DWBA predictions for the quadrupole deformation parameter is also discussed. In particular, the DWBA analysis allowed to determine the beta(C)(2) charge deformation parameter both in Ne-22 and Ne-24.
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Cembranos, J. A. R., de la Cruz-Dombriz, A., Gammaldi, V., Lineros, R. A., & Maroto, A. L. (2013). Reliability of Monte Carlo event generators for gamma-ray dark matter searches. J. High Energy Phys., 09(9), 077–21pp.
Abstract: We study the differences in the gamma-ray spectra simulated by four Monte Carlo event generator packages developed in particle physics. Two different versions of PYTHIA and two of HERWIG are analyzed, namely PYTHIA 6.418 and HERWIG 6.5.10 in Fortran and PYTHIA 8.165 and HERWIG 2.6.1 in C++. For all the studied channels, the intrinsic differences between them are shown to be significative and may play an important role in misunderstanding dark matter signals.
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Agarwalla, S. K., Prakash, S., & Sankar, S. U. (2013). Resolving the octant of theta(23) with T2K and NOvA. J. High Energy Phys., 07(7), 131–24pp.
Abstract: Preliminary results of MINOS experiment indicate that theta(23) is not maximal. Global fits to world neutrino data suggest two nearly degenerate solutions for theta(23): one in the lower octant (LO: theta(23) < 45 degrees) and the other in the higher octant (HO: theta(23) > 45 degrees). v(mu) -> v(e) oscillations in superbeam experiments are sensitive to the octant and are capable of resolving this degeneracy. We study the prospects of this resolution by the current T2K and upcoming NOvA experiments. Because of the hierarchy-delta(CP) degeneracy and the octant delta(CP) degeneracy, the impact of hierarchy on octant resolution has to be taken into account. As in the case of hierarchy determination, there exist favorable (unfavorable) values of delta(CP) for which octant resolution is easy (challenging). However, for octant resolution the unfavorable delta(CP) values of the neutrino data are favorable for the anti-neutrino data and vice-verse. This is in contrast to the case of hierarchy determination. In this paper, we compute the combined sensitivity of T2K and NOvA to resolve the octant ambiguity. If sin(2)theta(23) – 0.41, then NOvA can rule out all the values of theta(23) in HO at 2 sigma C.L., irrespective of the hierarchy and delta(CP). Addition of T2K data improves the octant sensitivity. If T2K were to have equal neutrino and anti-neutrino runs of 2.5 years each, a 2 sigma resolution of the octant becomes possible provided sin(2) theta(23) <= 0.43 or >= 0.58 for any value of delta(CP).
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