Tain, J. L., Agramunt, J., Algora, A., Aprahamian, A., Cano-Ott, D., Fraile, L. M., et al. (2015). The sensitivity of LaBr3:Ce scintillation detectors to low energy neutrons: Measurement and Monte Carlo simulation. Nucl. Instrum. Methods Phys. Res. A, 774, 17–24.
Abstract: The neutron sensitivity of a cylindrical circle minus 1.5 in x 1.5 in LaBr3:Ce scintillation detector was measured using quasi-monoenergetic neutron beams in the energy range from 40 keV to 2.5 MeV. In this energy range the detector is sensitive to gamma-rays generated in neutron inelastic and capture processes. The experimental energy response was compared with Monte Carlo simulations performed with the Geant4 simulation toolkit using the so-called High Precision Neutron Models. These models rely on relevant information stored in evaluated nuclear data libraries. The performance of the Geant4 Neutron Data Library as well as several standard nuclear data libraries was investigated. In the latter case this was made possible by the use of a conversion tool that allowed the direct use of the data from other libraries in Geant4. Overall it was found that there was good agreement with experiment for some of the neutron data bases like ENDF/B-VII.0 or JENDL-3.3 but not with the others such as ENDF/B-VI.8 or JEFF-3.1.
|
Doncel, M., Cederwall, B., Martin, S., Quintana, B., Gadea, A., Farnea, E., et al. (2015). Conceptual design of a high resolution Ge array with tracking and imaging capabilities for the DESPEC (FAIR) experiment. J. Instrum., 10, P06010–15pp.
Abstract: We present results of Monte Carlo simulations for the conceptual design of the high-resolution DESPEC Germanium Array Spectrometer (DEGAS) proposed for the Facility for Ion and Antiproton Research (FAIR) under construction at Darmstadt, Germany. The project is carried out in three phases, although only results for the two first phases will be addressed in this work. The first phase will consist of a re-arrangement of the EUROBALL cluster detectors previously used in the RISING campaign at GSI. The second phase is based on coupling AGATA-type triple-cluster detectors with EUROBALL cluster detectors in a compact geometry around the active ion implantation target of DESPEC.
|
Moline, A., Ibarra, A., & Palomares-Ruiz, S. (2015). Future sensitivity of neutrino telescopes to dark matter annihilations from the cosmic diffuse neutrino signal. J. Cosmol. Astropart. Phys., 06(6), 005–34pp.
Abstract: Cosmological observations and cold dark matter N-body simulations indicate that our Universe is populated by numerous halos, where dark matter particles annihilate, potentially producing Standard Model particles. In this paper we calculate the contribution to the diffuse neutrino background from dark matter annihilations in halos at all redshifts and we estimate the future sensitivity to the annihilation cross section of neutrino telescopes such as IceCube or ANTARES. We consider various parametrizations to describe the internal halo properties and for the halo mass function in order to bracket the theoretical uncertainty in the limits from the modeling of the cosmological annihilation flux. We find that observations of the cosmic diffuse neutrino flux at large angular distances from the galactic center lead to constraints on the dark matter annihilation cross section which are complementary to ( and for some extrapolations of the astrophysical parameters, better than) those stemming from observations of the Milky Way halo, especially for neutrino telescopes not pointing directly to the Milky Way center, as is the case of IceCube.
|
ATLAS Collaboration(Aad, G. et al), Alvarez Piqueras, D., Cabrera Urban, S., Castillo Gimenez, V., Costa, M. J., Fernandez Martinez, P., et al. (2015). Modelling Z -> ττ processes in ATLAS with τ-embedded Z -> μμ data. J. Instrum., 10, P09018–41pp.
Abstract: This paper describes the concept, technical realisation and validation of a largely data-driven method to model events with Z -> tau tau decays. In Z -> μμevents selected from proton-proton collision data recorded at root s = 8 TeV with the ATLAS experiment at the LHC in 2012, the Z decay muons are replaced by tau leptons from simulated Z -> tau tau decays at the level of reconstructed tracks and calorimeter cells. The tau lepton kinematics are derived from the kinematics of the original muons. Thus, only the well-understood decays of the Z boson and tau leptons as well as the detector response to the tau decay products are obtained from simulation. All other aspects of the event, such as the Z boson and jet kinematics as well as effects from multiple interactions, are given by the actual data. This so-called tau-embedding method is particularly relevant for Higgs boson searches and analyses in tau tau final states, where Z -> tau tau decays constitute a large irreducible background that cannot be obtained directly from data control samples. In this paper, the relevant concepts are discussed based on the implementation used in the ATLAS Standard Model H -> tau tau analysis of the full datataset recorded during 2011 and 2012.
|
Achterberg, A., Amoroso, S., Caron, S., Hendriks, L., Ruiz de Austri, R., & Weniger, C. (2015). A description of the Galactic Center excess in the Minimal Supersymmetric Standard Model. J. Cosmol. Astropart. Phys., 08(8), 006–27pp.
Abstract: Observations with the Fermi Large Area Telescope (LAT) indicate an excess in gamma rays originating from the center of our Galaxy. A possible explanation for this excess is the annihilation of Dark Matter particles. We have investigated the annihilation of neutralinos as Dark Matter candidates within the phenomenological Minimal Supersymmetric Standard Model (pMSSM). An iterative particle filter approach was used to search for solutions within the pMSSM. We found solutions that are consistent with astroparticle physics and collider experiments, and provide a fit to the energy spectrum of the excess. The neutralino is a Bino/Higgsino or Bino/Wino/Higgsino mixture with a mass in the range 84-92 GeV or 87-97 GeV annihilating into W bosons. A third solutions is found for a neutralino of mass 174-187 GeV annihilating into top quarks. The best solutions yield a Dark Matter relic density 0.06 < Omega h(2) < 0.13. These pMSSM solutions make clear forecasts for LHC, direct and indirect DM detection experiments. If the pMSSM explanation of the excess seen by Fermi-LAT is correct, a DM signal might be discovered soon.
|
