14 research outputs found
Modulation effect in the differential rate for Supersymmetric Dark Matter detection
The modulation effect in the direct detection of supersymmetric Cold Dark
Matter (CDM) particles is investigated. It is shown that, while normally the
modulation effect in the total event rate is small, , in some special
cases it becomes much larger. It also becomes more pronounced in the
differential event rate. It may thus be exploited to discriminate against
background.Comment: 17 LATEX pages, 4 Tables, 4 PostScript Figures included. Phys. Rev.
D, to be publishe
Searching for Supersymmetric Dark Matter - The Directional Rate and the Modulation Effect Due to Caustic Rings
The detection of the theoretically expected dark matter is central to
particle physics and cosmology. Current fashionable supersymmetric models
provide a natural dark matter candidate which is the lightest supersymmetric
particle (LSP). The allowed parameter space of such models combined with fairly
well understood physics (quark substructure of the nucleon and nuclear
structure) permit the evaluation of the event rate for LSP-nucleus elastic
scattering. The thus obtained event rates, which sensitively depend on the
allowed parameter space parameters, are usually very low or even undetectable.
So, for background reduction, one would like to exploit two nice features of
the reaction, the directional rate, which depends on the sun's direction of
motion and the modulation effect, i.e. the dependence of the event rate on the
earth's annual motion. In the present paper we study these phenomena in a
specific class of non isothermal models, which take into account the late
in-fall of dark matter into our galaxy, producing flows of caustic rings. We
find that the modulation effect arising from such models is smaller than that
found previously with isothermal symmetric velocity distributions and much
smaller compared to that obtained using a realistic asymmetric distribution
with enhanced dispersion in the galactocentric direction.Comment: 31 LATEX pages, 2 tables and 1 figure included. Accepted for
publication in Physical Review
The modulation effect for supersymmetric dark matter detection with asymmetric velocity dispersion
The detection of the theoretically expected dark matter is central to
particle physics cosmology. Current fashionable supersymmetric models provide a
natural dark matter candidate which is the lightest supersymmetric particle
(LSP). Such models combined with fairly well understood physics like the quark
substructure of the nucleon and the nuclear form factor and the spin response
function of the nucleus, permit the evaluation of the event rate for
LSP-nucleus elastic scattering. The thus obtained event rates are, however,
very low or even undetectable. So it is imperative to exploit the modulation
effect, i.e. the dependence of the event rate on the earth's annual motion. In
this review we study such a modulation effect in directional and undirectional
experiments. We calculate both the differential and the total rates using
symmetric as well as asymmetric velocity distributions. We find that in the
symmetric case the modulation amplitude is small, less than 0.07. There exist,
however, regions of the phase space and experimental conditions such that the
effect can become larger. The inclusion of asymmetry, with a realistic enhanced
velocity dispersion in the galactocentric direction, yields the bonus of an
enhanced modulation effect, with an amplitude which for certain parameters can
become as large as 0.46.Comment: 35 LATEX pages, 7 Tables, 8 PostScript Figures include