Tesi di dottorato di ricerca
Search of Neutralino Dark Matter with the ANTARES Neutrino Telescope
Settore scientifico disciplinare
Corso di studi
Relatore Prof. Flaminio, Vincenzo
- Dark Matter
Data inizio appello
Data di rilascio
The work presented in this thesis, developed in the framework of the ANTARES<br>experiment, aims at evaluating the performance of the detector in<br>the low energy region (10 GeV-5 TeV) where signals from neutralino DM<br>annihilation are expected. To make an immediate comparison with other<br>present and future neutrino telescopes, the effective area as a function of the<br>incident neutrino energy has been computed taking into account the effect<br>of different conditions of continuous random background rate and assessing<br>the efficiency of trigger and reconstruction algorithms. In the framework of<br>mSUGRA SUSY theories, we have used this information to calculate the<br>ANTARES sensitivity to signals from neutralino Dark Matter annihilation.<br>Through a MonteCarlo simulation of the full 12-line detector, the effective<br>area as a function of the neutralino mass has been evaluated in the case<br>of soft and hard annihilation. We have thus overcome the problem of scanning<br>the 5-dimensional mSUGRA parameter space and have achieved modelindependent<br>results for the effective area. We have then computed the upper<br>limit that can be set on the neutrino flux from neutralino annihilation after<br>one year of data taking with the full detector. The very same study has<br>been carried out to provide a preliminary estimate of the performance of a<br>km3 scale detector. Three geometries differing in the spatial distribution and<br>orientation of the PMTs have been simulated and the corresponding effective<br>area as function of the neutralino mass have been computed to establish<br>the achievable neutrino flux upper limit. Beyond the simulation work, the<br>analysis of the data collected in 2007 with the partially completed ANTARES<br>detector (5 lines out of 12) has been carried out: the runs taken at<br>low levels of background rate (golden runs) have been selected to establish<br>an experimental upper limit on a neutralino induced neutrino flux using the<br>Feldman and Cousins approach. After the evaluation of the effective area of<br>the 5-line detector, the upper limit on the neutrino flux has been converted<br>into an upper limit on the muon flux, achieving a close result to a recently<br>preliminary AMANDA measurement, despite the fact that the data taking<br>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<br>underline that significant improvements of the results here presented can be<br>achieved with the analysis of more, possibly full-detector, data. The simulation<br>of the 12-line detector already tells us that we could establish an upper<br>limit on the neutrino flux about two order of magnitude better. As far as<br>the km3 studies are concerned, possible improvements include the study of<br>optimised trigger algorithms, of the corresponding effect on the effective area<br>and on the resulting upper limits on the neutrino flux.
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