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Search for Gamma-ray Lines from Dark Matter with the Fermi Large Area Telescope
KTH, School of Engineering Sciences (SCI), Physics, Particle and Astroparticle Physics.
2010 (English)Doctoral thesis, monograph (Other academic)
##### Abstract [en]

Dark matter (DM) constitutes one of the most intriguing but so far unresolved issues in physics. In many extensions of the Standard Model of particle physics, the existence of a stable Weakly Interacting Massive Particle (WIMP) is predicted. The WIMP is an excellent DM particle candidate. One of the most interesting scenarios is the creation of monochromatic gamma-rays from the annihilation or decay of these particles. This type of signal would represent a “smoking gun” for DM, since no other known astrophysical process should be able to produce it.

In this thesis, the search for spectral lines with the Large Area Telescope (LAT) onboard the Fermi Gamma-ray Space Telescope (Fermi) is presented. The satellite was successfully launched from Cape Canaveral in Florida, USA, on 11 June, 2008. The energy resolution and performance of the detector are both key factors in the search and are investigated here using beam test data, taken at CERN in 2006 with a scaled-down version of the Fermi-LAT instrument. A variety of statistical methods, based on both hypothesis tests and confidence interval calculations, are then reviewed and tested in terms of their statistical power and coverage.

A selection of the statistical methods are further developed into peak finding algorithms and applied to a simulated data set called obssim2, which corresponds to one year of observations with the Fermi-LAT instrument, and to almost one year of Fermi-LAT data in the energy range 20–300 GeV. The analysis on Fermi-LAT data yielded no detection of spectral lines, so limits are placed on the velocity-averaged cross-section, $<\sigma v>_{\gamma X}$, and the decay lifetime, $\tau_{\gamma X}$, and theoretical implications are discussed.

##### Place, publisher, year, edition, pages
Stockholm: KTH , 2010. , viii, 152 p.
##### Series
Trita-FYS, ISSN 0280-316X ; 2010:28
##### Keyword [en]
Fermi, Large Area Telescope, gamma-rays, dark matter, spectral lines, beam test
##### National Category
Physical Sciences Subatomic Physics
##### Identifiers
ISBN: 978-91-7415-672-0OAI: oai:DiVA.org:kth-12853DiVA: diva2:319356
##### Public defence
2010-06-07, FA32, AlbaNova Universitetscentrum, Roslagstullsbacken 21, Stockholm, 14:00 (English)
GLAST
##### Note
QC20100525Available from: 2010-05-25 Created: 2010-05-17 Last updated: 2010-06-30Bibliographically approved

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