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Browsing by Author "Ullio, Piero"

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Browsing by Author "Ullio, Piero"

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  • Arcadi, Giorgio; Ullio, Piero (American Physical Society, 2011-08-12)
    Non-thermal dark matter generation is an appealing alternative to the standard paradigm of thermal WIMP dark matter. We reconsider non-thermal production mechanisms in a systematic way, and develop a numerical code ...
  • Evoli, Carmelo; Cholis, Ilias; Grasso, Dario; Maccione, Luca; Ullio, Piero (American Physical Society, 2012-06-07)
    The latest years have seen steady progresses in WIMP dark matter (DM) searches, with hints of possible signals suggested by both direct and indirect detection experiments. Antiprotons can play a key role validating ...
  • Arcadi, Giorgio; Ullio, Piero (IOP Publishing, 2011-11-28)
    We reconsider non-thermal production of WIMP dark matter in a systematic way and using a numerical code for accurate computations of dark matter relic densities. Candidates with large pair annihilation rates are favored, ...
  • Regis, Marco (SISSA, 2008-10-15)
    Weakly interacting massive particles (WIMPs) are among the leading candidates for the dark matter (DM) component in the Universe. The thesis presents a review of the current status of the DM problem, focussing on the WIMP ...
  • Ullio, Piero; Bergstrom, Lars; Edsjo, Joakim; Lacey, Cedric G. (American Physical Society, 2002)
    We investigate the prospects of detecting weakly interacting massive particle (WIMP) dark matter by measuring the contribution to the extragalactic gamma-ray radiation induced, in any dark matter halo and at all redshifts, ...
  • Regis, Marco; Serone, Marco; Ullio, Piero (2007-01-31)
    We show that a recently constructed five-dimensional (5D) model with gauge-Higgs unification and explicit Lorentz symmetry breaking in the bulk, provides a natural dark matter candidate. This is the lightest Kaluza-Klein ...
  • Borzumati, Francesca; Bringmann, Torsten; Ullio, Piero (2008-04-22)
    The generation of dark matter in late decays of quasi-stable massive particles has been proposed as a viable framework to address the excess of power found in numerical N-body simulations for cold dark matter cosmologies. ...
  • Provenza, Alessio; Quiros, Mariano; Ullio, Piero (2006-09-07)
    We consider the split extended (N=2) supersymmetry scenario recently proposed by Antoniadis et al. [hep-ph/0507192] as a realistic low energy framework arising from intersecting brane models. While all scalar superpartners ...
  • Ullio, Piero; HongSheng Zhao; Kamionkowski, Marc (American Physical Society, 2001)
    The past growth of the central black hole (BH) might have enhanced the density of cold dark matter halo particles at the Galactic center. We compute this effect in realistic growth models of the present (2-3)*10**6 solar ...
  • Gondolo, Paolo; Edsjo, Joakim; Ullio, Piero; Bergstrom, Lars; Schelke, Mia; Baltz, Edward A. (IOP Publishing, 2004-07-14)
    The question of the nature of the dark matter in the Universe remains one of the most outstanding unsolved problems in basic science. One of the best motivated particle physics candidates is the lightest supersymmetric ...
  • Colafrancesco, Sergio; Profumo, Stefano; Ullio, Piero (2007-09-03)
    We explore the possible signatures of dark matter pair annihilations in the nearby dwarf spheroidal galaxy Draco. After investigating the mass models for Draco in the light of available observational data, we carefully ...
  • Cholis, Ilias; Tavakoli, Maryam; Evoli, Carmelo; Maccione, Luca; Ullio, Piero (IOP Publishing, 2012-05-03)
    We study the high latitude (|b|>10) diffuse gamma-ray emission in the Galaxy in light of the recently published data from the Fermi collaboration at energies between 100 MeV and 100 GeV. The unprecedented accuracy in ...
  • Colafrancesco, Sergio; de Bernardis, Paolo; Masi, Silvia; Polenta, G.; Ullio, Piero (2007-09-03)
    The cluster 1ES0657-556 is an ideal astrophysical laboratory to study the distribution and the nature of Dark Matter because this last component is spatially separated from the intracluster gas. We show that microwave ...
  • Edsjo, Joakim; Schelke, Mia; Ullio, Piero (IOP Publishing, 2004-09-10)
    We perform a detailed analysis of the detection prospects of neutralino dark matter in the mSUGRA framework. We focus on models with a thermal relic density, estimated with high accuracy using the DarkSUSY package, in ...
  • Provenza, Alessio; Quiros, Mariano; Ullio, Piero (2006-02-17)
    It has recently been shown that the electroweak baryogenesis mechanism is feasible in Standard Model extensions containing extra fermions with large Yukawa couplings. We show here that the lightest of these fermionic fields ...
  • Cesarini, Alessandro; Fucito, Francesco; Lionetto, Andrea; Morselli, Aldo; Ullio, Piero (Elsevier, 2004-06)
    The EGRET telescope has identified a gamma-ray source at the Galactic center. We point out here that the spectral features of this source are compatible with the gamma-ray flux induced by pair annihilations of dark matter ...
  • Ullio, Piero (IOP Publishing, 2001)
    We consider a model for neutralino dark matter candidates arising in anomaly-mediated supersymmetry breaking schemes, and examine its testability through the search for exotic cosmic rays produced by neutralino pair ...
  • Bazzocchi, Federica; Fabbrichesi, Marco; Ullio, Piero (2007-09-03)
    We discuss a minimal extension to the standard model in which there are two Higgs bosons and, in addition to the usual fermion content, two fermion doublets and one fermion singlet. The little hierachy problem is solved ...
  • Catena, Riccardo; Ullio, Piero (IOP Publishing, 2012-05-03)
    We present a new determination of the local dark matter phase-space density. This result is obtained implementing, in the limit of isotropic velocity distribution and spherical symmetry, Eddington's inversion formula, ...
  • Hryczuk, Andrzej (SISSA, 2012-09-24)
    In this thesis we analyze the importance of the one-loop corrections and the non-perturbative Sommerfeld enhancement on the dark matter thermal relic density and indirect detection signals. We discuss general properties of ...