Bounds on Cross-sections and Lifetimes for Dark Matter Annihilation and Decay into Charged Leptons from Gamma-ray Observations of Dwarf Galaxies

Journal Article · Fri Jun 19 04:00:00 EDT 2009 · Physical Review D

DOI:https://doi.org/10.1103/PhysRevD.80.023506· OSTI ID:957433

Essig, Rouven; Sehgal, Neelima; Strigari, Louis E

We provide conservative bounds on the dark matter cross-section and lifetime from final state radiation produced by annihilation or decay into charged leptons, either directly or via an intermediate particle {phi}. Our analysis utilizes the experimental gamma-ray flux upper limits from four Milky Way dwarf satellites: HESS observations of Sagittarius and VERITAS observations of Draco, Ursa Minor, and Willman 1. Using 90% confidence level lower limits on the integrals over the dark matter distributions, we find that these constraints are largely unable to rule out dark matter annihilations or decays as an explanation of the PAMELA and ATIC/PPB-BETS excesses. However, if there is an additional Sommerfeld enhancement in dwarfs, which have a velocity dispersion {approx} 10 to 20 times lower than that of the local Galactic halo, then the cross-sections for dark matter annihilating through {phi}'s required to explain the excesses are very close to the cross-section upper bounds from Willman 1. Dark matter annihilation directly into {tau}'s is also marginally ruled out by Willman 1 as an explanation of the excesses, and the required cross-section is only a factor of a few below the upper bound from Draco. Finally, we make predictions for the gamma-ray flux expected from the dwarf galaxy Segue 1 for the Fermi Gamma-ray Space Telescope. We find that for a sizeable fraction of the parameter space in which dark matter annihilation into charged leptons explains the PAMELA excess, Fermi has good prospects for detecting a gamma-ray signal from Segue 1 after one year of observation.

• Research Organization: Stanford Linear Accelerator Center (SLAC)
• Sponsoring Organization: USDOE
• DOE Contract Number: AC02-76SF00515
• OSTI ID: 957433
• Report Number(s): SLAC-PUB-13548; arXiv:0902.4750
• Journal Information: Physical Review D, Journal Name: Physical Review D; ISSN PRVDAQ; ISSN 1550-7998
• Country of Publication: United States
• Language: English

Related Subjects

71 CLASSICAL AND QUANTUM MECHANICS
GENERAL PHYSICS
72 PHYSICS OF ELEMENTARY PARTICLES AND FIELDS
73 NUCLEAR PHYSICS AND RADIATION PHYSICS
ANNIHILATION
CROSS SECTIONS
DECAY
GALAXIES
LEPTONS
LIFETIME
MILKY WAY
NONLUMINOUS MATTER
Phenomenology-HEP
ASTRO
HEPPH
RADIATIONS
SATELLITES
VELOCITY