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Digital archive of theses discussed at the University of Pisa

 

Thesis etd-01202009-175922


Thesis type
Tesi di dottorato di ricerca
Author
CASTORINA, ERSILIO
URN
etd-01202009-175922
Thesis title
Search of Neutralino Dark Matter with the ANTARES Neutrino Telescope
Academic discipline
FIS/01
Course of study
FISICA
Supervisors
Relatore Prof. Flaminio, Vincenzo
Keywords
  • Dark Matter
  • Neutralino
  • Neutrino
  • Telescope
Graduation session start date
08/03/2009
Availability
Withheld
Release date
08/03/2049
Summary
The work presented in this thesis, developed in the framework of the ANTARES
experiment, aims at evaluating the performance of the detector in
the low energy region (10 GeV-5 TeV) where signals from neutralino DM
annihilation are expected. To make an immediate comparison with other
present and future neutrino telescopes, the effective area as a function of the
incident neutrino energy has been computed taking into account the effect
of different conditions of continuous random background rate and assessing
the efficiency of trigger and reconstruction algorithms. In the framework of
mSUGRA SUSY theories, we have used this information to calculate the
ANTARES sensitivity to signals from neutralino Dark Matter annihilation.
Through a MonteCarlo simulation of the full 12-line detector, the effective
area as a function of the neutralino mass has been evaluated in the case
of soft and hard annihilation. We have thus overcome the problem of scanning
the 5-dimensional mSUGRA parameter space and have achieved modelindependent
results for the effective area. We have then computed the upper
limit that can be set on the neutrino flux from neutralino annihilation after
one year of data taking with the full detector. The very same study has
been carried out to provide a preliminary estimate of the performance of a
km3 scale detector. Three geometries differing in the spatial distribution and
orientation of the PMTs have been simulated and the corresponding effective
area as function of the neutralino mass have been computed to establish
the achievable neutrino flux upper limit. Beyond the simulation work, the
analysis of the data collected in 2007 with the partially completed ANTARES
detector (5 lines out of 12) has been carried out: the runs taken at
low levels of background rate (golden runs) have been selected to establish
an experimental upper limit on a neutralino induced neutrino flux using the
Feldman and Cousins approach. After the evaluation of the effective area of
the 5-line detector, the upper limit on the neutrino flux has been converted
into an upper limit on the muon flux, achieving a close result to a recently
preliminary AMANDA measurement, despite the fact that the data taking
period of ANTARES golden runs was only about 1/10 of a year and that the detector was only almost half completed. This consideration bring us to
underline that significant improvements of the results here presented can be
achieved with the analysis of more, possibly full-detector, data. The simulation
of the 12-line detector already tells us that we could establish an upper
limit on the neutrino flux about two order of magnitude better. As far as
the km3 studies are concerned, possible improvements include the study of
optimised trigger algorithms, of the corresponding effect on the effective area
and on the resulting upper limits on the neutrino flux.
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