GLEAM for DMWG

1. GLEAM for DMWG Eduardo do Couto e Silva Oct 23 , 2002 SLAC

2. Main objective Develop a likelihood program to search for photons from neutralino annihilations using the new GLEAM Monte Carlo. This work leverages on the development of the data analysis infrastructure for LAT I&T maintained by Xin Chen, who was kind enough to provide us with his “nuggets of wisdom”

3. Shopping list… • Source flux for different MSSM models (e.g DarkSUSY). – See A. Morselli’s talk. • Background flux (e.g EGRET parametrization used in Bergstrom et al Astr. Phys 9 (1998), 137.) • Orbit model for GLAST – See T. Burnett’s talk. • Energy resolution – See CAL group report in LAT IDT meeting • PSF – See W. Atwood’s report in LAT IDT meeting • Likelihood program

4. The approach • Develop a simple likelihood program and interfaces the main ingredients described in the previous page • Develop software infrastructure for systematic studies • Implement a more sophisticated likelihood approach to maximize our sensitivity based on details of the LAT design.

5. Signal and Background Likelihood of event i to be a neutralino signal we assume s = b . Es Likelihood of event i to be a background (To be replaced by measured spectrum from GLEAM with including orbital effects and appropriate normalizations from DarkSUSY)

6. Extended Likelihood Fit parameters Nbg = number of expected background events Ns = number of expected photons a = power law coefficient Es = neutralino energy

9. An example of Fitted Parameters Input value = 60 Input value = 50 Input value = 1156 Input value = 2.2

10. LAT sensitivity Each point corresponds to 1000 MC experiments And assumes a 5 sigma detection threshold D E/E

11. Summary • We have developed a simple likelihood code and some infrastructure to run GLEAM • We have started to run GLEAM with the orbit corrections (not presented in this talk) • We are eager to work with the v3 release of GLEAM