ATLAS Collaboration(Aad, G. et al), Amoros, G., Cabrera Urban, S., Castillo Gimenez, V., Costa, M. J., Ferrer, A., et al. (2012). Measurement of the top quark mass with the template method in the t(t)over-bar -> lepton plus jets channel using ATLAS data. Eur. Phys. J. C, 72(6), 2046–30pp.
Abstract: The top quark mass has been measured using the template method in the t (t) over bar -> lepton + jets channel based on data recorded in 2011 with the ATLAS detector at the LHC. The data were taken at a proton-proton centre-of-mass energy of root s = 7 TeV and correspond to an integrated luminosity of 1.04 fb(-1). The analyses in the e + jets and μ+ jets decay channels yield consistent results. The top quark mass is measured to be m(top) = 174.5 +/- 0.6(stat) +/- 2.3(syst) GeV.
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NEXT Collaboration(Alvarez, V. et al), Carcel, S., Cervera-Villanueva, A., Diaz, J., Ferrario, P., Gil, A., et al. (2012). NEXT-100 Technical Design Report (TDR). Executive summary. J. Instrum., 7, T06001–34pp.
Abstract: In this Technical Design Report (TDR) we describe the NEXT-100 detector that will search for neutrinoless double beta decay (beta beta 0v) in Xe-136 at the Laboratorio Subterraneo de Canfranc (LSC), in Spain. The document formalizes the design presented in our Conceptual Design Report (CDR): an electroluminescence time projection chamber, with separate readout planes for calorimetry and tracking, located, respectively, behind cathode and anode. The detector is designed to hold a maximum of about 150 kg of xenon at 15 bar, or 100 kg at 10 bar. This option builds in the capability to increase the total isotope mass by 50% while keeping the operating pressure at a manageable level. The readout plane performing the energy measurement is composed of Hamamatsu R11410-10 photomultipliers, specially designed for operation in low-background, xenon-based detectors. Each individual PMT will be isolated from the gas by an individual, pressure resistant enclosure and will be coupled to the sensitive volume through a sapphire window. The tracking plane consists in an array of Hamamatsu S10362-11-050P MPPCs used as tracking pixels. They will be arranged in square boards holding 64 sensors (8 x 8) with a 1-cm pitch. The inner walls of the TPC, the sapphire windows and the boards holding the MPPCs will be coated with tetraphenyl butadiene (TPB), a wavelength shifter, to improve the light collection.
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Molina, R., Xiao, C. W., & Oset, E. (2012). J/psi reaction mechanisms and suppression in the nuclear medium. Phys. Rev. C, 86(1), 014604–9pp.
Abstract: Recent studies of the interaction of vector mesons with nuclei make possible and opportune the study of the interaction of the J/psi with nuclei and the investigation of the origin of the J/psi suppression in its propagation thorough a nuclear medium. We observe that the transition of J/psi N to VN with V being a light vector, rho, omega, phi, together with the inelastic channels, J/psi N -> (D) over bar Lambda(c) and J/psi N -> (D) over bar Sigma(c), leads to a particular shape of the inelastic cross section. Analogously, we consider the mechanisms where the exchanged D collides with a nucleon and gives pi Lambda(c) or pi Sigma(c). The cross section has a peak around root s = 4415 MeV, where the J/psi N couples to a resonance predicted recently. We study the transparency ratio for electron-induced J/psi production in nuclei at about 10 GeV and find that 30-35% of the J/psi produced in heavy nuclei are absorbed inside the nucleus. This ratio is in line with depletions of J/psi through matter observed in other reactions.
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Aceti, F., & Oset, E. (2012). Wave functions of composite hadron states and relationship to couplings of scattering amplitudes for general partial waves. Phys. Rev. D, 86(1), 014012–12pp.
Abstract: In this paper we present the connection between scattering amplitudes in momentum space and wave functions in coordinate space, generalizing previous work done for s-waves to any partial wave. The relationship to the wave function of the residues of the scattering amplitudes at the pole of bound states or resonances is investigated in detail. A sum rule obtained for the couplings provides a generalization to coupled channels, any partial wave and bound or resonance states, of Weinberg's compositeness condition, which was only valid for weakly bound states in one channel and s-wave. An example, requiring only experimental data, is shown for the rho meson indicating that it is not a composite particle of pi pi and K (K) over bar but something else.
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Castorina, E., Franca, U., Lattanzi, M., Lesgourgues, J., Mangano, G., Melchiorri, A., et al. (2012). Cosmological lepton asymmetry with a nonzero mixing angle theta(13). Phys. Rev. D, 86(2), 023517–11pp.
Abstract: While the baryon asymmetry of the Universe is nowadays well measured by cosmological observations, the bounds on the lepton asymmetry in the form of neutrinos are still significantly weaker. We place limits on the relic neutrino asymmetries using some of the latest cosmological data, taking into account the effect of flavor oscillations. We present our results for two different values of the neutrino mixing angle theta(13), and show that for large theta(13) the limits on the total neutrino asymmetry become more stringent, diluting even large initial flavor asymmetries. In particular, we find that the present bounds are still dominated by the limits coming from big bang nucleosynthesis, while the limits on the total neutrino mass from cosmological data are essentially independent of theta(13). Finally, we perform a forecast for Cosmic Origins Explorer, taken as an example of a future cosmic microwave background experiment, and find that it could improve the limits on the total lepton asymmetry approximately by up to a factor 6.6.
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