1,304 research outputs found
Supersymmetric Extension of the Minimal Dark Matter Model
The minimal dark matter model is given a supersymmetric extension. A super
SU(2)L quintuplet is introduced with its fermionic neutral component still
being the dark matter, the dark matter particle mass is about 19.7 GeV. Mass
splitting among the quintplet due to supersymmetry particles is found to be
negligibly small compared to the electroweak corrections. Other properties of
this supersymmetry model are studied, it has the solutions to the PAMELA and
Fermi-LAT anomaly, the predictions in higher energies need further experimental
data to verify.Comment: 14 pages, 7 figures, accepted for publication in Chinese Physics C,
typos correcte
Turismo e artigianato del \u201cfalso d\u2019autore\u201d per lo sviluppo locale del comune di Centuripe
L\u2019 Etna: un percorso attraverso l\u2019immaginario, la consapevolezza del rischio e la gestione del territorio\u201d,
anche in, Annali della Facolt\ue0 di Economia, Catania, anno L, 2004
The Centre-Periphery Dialectics in Eastern Sicily Retail System. An Exploratory Research
This paper aims at scrutinizing from an historical perspective the deep trans-formations shaped by retail spaces and new consumption patterns challenging long-entrenched dichotomies, such as the centre-periphery one. In particular, the exploratory research explores the territorial reconfiguration of the main Eastern Sicily metropol-itan areas, Catania and Messina, from the lens of the retail geography, namely after the diffusion of new suburban retail formats which have completely upset deeply-rooted relations between urban core and suburban rings
Thermal decoupling and the smallest subhalo mass in dark matter models with Sommerfeld-enhanced annihilation rates
We consider dark matter consisting of weakly interacting massive particles
(WIMPs) and revisit in detail its thermal evolution in the early universe, with
a particular focus on models where the annihilation rate is enhanced by the
Sommerfeld effect. After chemical decoupling, or freeze-out, dark matter no
longer annihilates but is still kept in local thermal equilibrium due to
scattering events with the much more abundant standard model particles. During
kinetic decoupling, even these processes stop to be effective, which eventually
sets the scale for a small-scale cutoff in the matter density fluctuations.
Afterwards, the WIMP temperature decreases more quickly than the heat bath
temperature, which causes dark matter to reenter an era of annihilation if the
cross-section is enhanced by the Sommerfeld effect. Here, we give a detailed
and self-consistent description of these effects. As an application, we
consider the phenomenology of simple leptophilic models that have been
discussed in the literature and find that the relic abundance can be affected
by as much two orders of magnitude or more. We also compute the mass of the
smallest dark matter subhalos in these models and find it to be in the range of
about 10^{-10} to 10 solar masses; even much larger cutoff values are possible
if the WIMPs couple to force carriers lighter than about 100 MeV. We point out
that a precise determination of the cutoff mass allows to infer new limits on
the model parameters, in particular from gamma-ray observations of galaxy
clusters, that are highly complementary to existing constraints from g-2 or
beam dump experiments.Comment: minor changes to match published versio
PAMELA and FERMI-LAT limits on the neutralino-chargino mass degeneracy
Searches for Dark Matter (DM) particles with indirect detection techniques
have reached important milestones with the precise measurements of the
anti-proton and gamma-ray spectra, notably by the PAMELA and FERMI-LAT
experiments. While the gamma-ray results have been used to test the thermal
Dark Matter hypothesis and constrain the Dark Matter annihilation cross section
into Standard Model (SM) particles, the anti-proton flux measured by the PAMELA
experiment remains relatively unexploited. Here we show that the latter can be
used to set a constraint on the neutralino-chargino mass difference. To
illustrate our point we use a Supersymmetric model in which the gauginos are
light, the sfermions are heavy and the Lightest Supersymmetric Particle (LSP)
is the neutralino. In this framework the W^+ W^- production is expected to be
significant, thus leading to large anti-proton and gamma-ray fluxes. After
determining a generic limit on the Dark Matter pair annihilation cross section
into W^+ W^- from the anti-proton data only, we show that one can constrain
scenarios in which the neutralino-chargino mass difference is as large as ~ 20
GeV for a mixed neutralino (and intermediate choices of the anti-proton
propagation scheme). This result is consistent with the limit obtained by using
the FERMI-LAT data. As a result, we can safely rule out the pure wino
neutralino hypothesis if it is lighter than 450 GeV and constitutes all the
Dark Matter.Comment: 22page
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