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Nieves J.,University of Valencia | Sanchez F.,Institute Of Fisica Daltes Energies Ifae | Simo I.R.,University of Granada | Vacas M.J.V.,University of Valencia
Physical Review D - Particles, Fields, Gravitation and Cosmology | Year: 2012

We show that because of the multinucleon mechanism effects, the algorithm used to reconstruct the neutrino energy is not adequate when dealing with quasielastic-like events, and a distortion of the total flux-unfolded cross-section shape is produced. This amounts to a redistribution of strength from high to low energies, which gives rise to a sizable excess (deficit) of low (high) energy neutrinos. This distortion of the shape leads to a good description of the MiniBooNE unfolded charged current quasielastic-like cross sections published by A.A. Aguilar-Arevalo [(MiniBooNE Collaboration), Phys. Rev. DPRVDAQ1550-7998 81, 092005 (2010)]10.1103/PhysRevD.81.092005. However, these changes in the shape are artifacts of the unfolding process that ignores multinucleon mechanisms. © 2012 American Physical Society.

Aguilar-Saavedra J.A.,University of Granada | Juste A.,Catalan Institution for Research and Advanced Studies | Juste A.,Institute Of Fisica Daltes Energies Ifae | Rubbo F.,Institute Of Fisica Daltes Energies Ifae
Physics Letters, Section B: Nuclear, Elementary Particle and High-Energy Physics | Year: 2012

We propose a kinematical enhancement of the tt̄ charge asymmetry at the LHC by selecting events with the tt̄ centre of mass frame highly boosted along the beam axis. This kinematical selection increases the asymmetries and their significance up to a factor of two in a rather model-independent fashion. Hence, it can be a perfect complement to enhance model discrimination at the LHC. © 2011 Elsevier B.V.

Casas J.A.,Institute Fisica Teorica | Espinosa J.R.,Institute Of Fisica Daltes Energies Ifae | Espinosa J.R.,Catalan Institution for Research and Advanced Studies | Moreno J.M.,Institute Fisica Teorica
Physics Letters, Section B: Nuclear, Elementary Particle and High-Energy Physics | Year: 2016

One of the most exciting explanations advanced for the recent diphoton excess found by ATLAS and CMS is in terms of sgoldstino decays: a signal of low-energy supersymmetry-breaking scenarios. The sgoldstino, a scalar, couples directly to gluons and photons, with strength related to gaugino masses, that can be of the right magnitude to explain the excess. However, fitting the suggested resonance width, Γ. ≃. 45 GeV, is not so easy. In this paper we explore efficient possibilities to enhance the sgoldstino width, via the decay into two Higgses, two Higgsinos and through mixing between the sgoldstino and the Higgs boson. In addition, we present an alternative and more efficient mechanism to generate a mass splitting between the scalar and pseudoscalar components of the sgoldstino, which has been suggested as an interesting alternative explanation to the apparent width of the resonance. © 2016 The Author(s).

Gran R.,University of Minnesota | Nieves J.,University of Valencia | Sanchez F.,Institute Of Fisica Daltes Energies Ifae | Vacas M.J.V.,University of Valencia
Physical Review D - Particles, Fields, Gravitation and Cosmology | Year: 2013

We extend to 10 GeV results from a microscopic calculation of charged-current neutrino-nucleus reactions that do not produce a pion in the final state. For the class of events coming from neutrino interactions with two nucleons producing two holes (2p2h), limiting the calculation to three-momentum transfers less than 1.2 GeV produces a two-dimensional distribution in momentum and energy transfer that is roughly constant as a function of energy. The cross section for 2p2h interactions approximately scales with the number of nucleons for isoscalar nuclei, similar to the quasi-elastic cross section. When limited to momentum transfers below 1.2 GeV, the cross section is 26% of the quasi-elastic cross section at 3 GeV, but 14% if we neglect a Δ1232 resonance absorption component. The same quantities are 33% and 17% for antineutrinos. For the quasi-elastic interactions, the full nuclear model with long range correlations produces an even larger, but approximately constant distortion of the shape of the four-momentum transfer at all energies above 2 GeV. The 2p2h enhancement and long-range correlation distortions to the cross section for these interactions are significant enough they should be observable in precision experiments to measure neutrino oscillations and neutrino interactions at these energies, but also balance out and produce less total distortion than each effect does individually. © 2013 American Physical Society.

Rico J.,Institute Of Fisica Daltes Energies Ifae
Nuclear and Particle Physics Proceedings | Year: 2016

MAGIC is a system of two 17-m diameter Cherenkov telescopes, located at the Observatorio del Roque de los Muchachos, in the Canary island La Palma (Spain). MAGIC performs astronomical observations of gamma-ray sources in the energy range between 50 GeV and 10 TeV. The first MAGIC telescope has been operating since 2004, and in 2009 the system was completed with the second one. During 2011 and 2012 the electronics for the readout system were fully upgraded, and the camera of the first telescope replaced. After that, no major hardware interventions are foreseen in the next years, and the experiment has undertaken a final period of steady astronomical observations.MAGIC studies particle acceleration in the most violent cosmic environments, such as active galactic nuclei, gamma-ray bursts, pulsars, supernova remnants or binary systems. In addition, it addresses some fundamental questions of Physics, such as the origin of Galactic cosmic rays and the nature of dark matter. Moreover, by observing the gamma-ray emission from sources at cosmological distances, we measure the intensity and evolution of the extragalactic background radiation, and perform tests of Lorentz Invariance.In this paper I present the status and some of the latest results of the MAGIC gamma-ray telescopes. © 2015 Elsevier B.V.

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