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Agullo, I., Navarro-Salas, J., Olmo, G. J., & Parker, L. (2011). Remarks on the renormalization of primordial cosmological perturbations. Phys. Rev. D, 84(10), 107304–5pp.
Abstract: We briefly review the need to perform renormalization of inflationary perturbations to properly work out the physical power spectra. We also summarize the basis of (momentum-space) renormalization in curved spacetime and address several misconceptions found in recent literature on this subject.
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ANTARES Collaboration(Aguilar, J. A. et al), Bigongiari, C., Dornic, D., Emanuele, U., Gomez-Gonzalez, J. P., Hernandez-Rey, J. J., et al. (2011). Time calibration of the ANTARES neutrino telescope. Astropart Phys., 34(7), 539–549.
Abstract: The ANTARES deep-sea neutrino telescope comprises a three-dimensional array of photomultipliers to detect the Cherenkov light induced by upgoing relativistic charged particles originating from neutrino interactions in the vicinity of the detector. The large scattering length of light in the deep sea facilitates an angular resolution of a few tenths of a degree for neutrino energies exceeding 10 TeV. In order to achieve this optimal performance, the time calibration procedures should ensure a relative time calibration between the photomultipliers at the level of similar to 1 ns. The methods developed to attain this level of precision are described.
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Aguilar, A. C., Binosi, D., & Papavassiliou, J. (2011). Dynamical equation of the effective gluon mass. Phys. Rev. D, 84(8), 085026–19pp.
Abstract: In this article, we derive the integral equation that controls the momentum dependence of the effective gluon mass in the Landau gauge. This is accomplished by means of a well-defined separation of the corresponding “one-loop dressed” Schwinger-Dyson equation into two distinct contributions, one associated with the mass and one with the standard kinetic part of the gluon. The entire construction relies on the existence of a longitudinally coupled vertex of nonperturbative origin, which enforces gauge invariance in the presence of a dynamical mass. The specific structure of the resulting mass equation, supplemented by the additional requirement of a positive-definite gluon mass, imposes a rather stringent constraint on the derivative of the gluonic dressing function, which is comfortably satisfied by the large-volume lattice data for the gluon propagator, both for SU(2) and SU(3). The numerical treatment of the mass equation, under some simplifying assumptions, is presented for the aforementioned gauge groups, giving rise to a gluon mass that is a nonmonotonic function of the momentum. Various theoretical improvements and possible future directions are briefly discussed.
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Aguilar, A. C., & Papavassiliou, J. (2011). Chiral symmetry breaking with lattice propagators. Phys. Rev. D, 83(1), 014013–17pp.
Abstract: We study chiral symmetry breaking using the standard gap equation, supplemented with the infrared-finite gluon propagator and ghost dressing function obtained from large-volume lattice simulations. One of the most important ingredients of this analysis is the non-Abelian quark-gluon vertex, which controls the way the ghost sector enters into the gap equation. Specifically, this vertex introduces a numerically crucial dependence on the ghost dressing function and the quark-ghost scattering amplitude. This latter quantity satisfies its own, previously unexplored, dynamical equation, which may be decomposed into individual integral equations for its various form factors. In particular, the scalar form factor is obtained from an approximate version of the “one-loop dressed” integral equation, and its numerical impact turns out to be rather considerable. The detailed numerical analysis of the resulting gap equation reveals that the constituent quark mass obtained is about 300 MeV, while fermions in the adjoint representation acquire a mass in the range of (750-962) MeV.
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Estevez, E. et al, Algora, A., Rubio, B., Bernabeu, J., Nacher, E., Tain, J. L., et al. (2011). beta-decay study of (150)Er, (152)Yb, and (156)Yb: Candidates for a monoenergetic neutrino beam facility. Phys. Rev. C, 84(3), 034304–6pp.
Abstract: The beta decays of (150)Er, (152)Yb, and (156)Yb nuclei are investigated using the total absorption spectroscopy technique. These nuclei can be considered possible candidates for forming the beam of a monoenergetic neutrino beam facility based on the electron capture (EC) decay of radioactive nuclei. Our measurements confirm that for the cases studied the EC decay proceeds mainly to a single state in the daughter nucleus.
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