Generic dark matter signature for gamma-ray telescopes

by Prof. Wai Yee Keung (University o Illinois)

Friday Apr 15, 2011, 3:00 PM → 4:30 PM Pacific/Honolulu

417 (Watanabe Hall)

SPECIAL HIGH ENERGY PHYSICS SEMINAR We describe a characteristic signature of dark matter (DM) annihilation or decay into gamma-rays. We show that if the total angular momentum of the initial DM particle(s) vanishes, and helicity suppression operates to prevent annihilation/decay into light fermion pairs, then the amplitude for the dominant 3-body final state e+e- gamma has a unique form dictated by gauge invariance. This amplitude and the corresponding energy spectra hold for annihilation of DM Majorana fermions or self-conjugate scalars, and for decay of DM scalars, thus encompassing a variety of possibilities. Within this scenario, we analyze Fermi LAT, PAMELA and HESS data, and predict a hint in future Fermi gamma-ray data that portends a striking signal at atmospheric Cherenkov telescopes (ACTs). In charge: Xerxes Tata