Is the PAMELA positron excess winos?

Journal Article · Sun Feb 15 04:00:00 EST 2009 · Physical Review. D, Particles Fields

DOI:https://doi.org/10.1103/PHYSREVD.79.043506· OSTI ID:21259989

Grajek, Phill; Kane, Gordon L; Phalen, Daniel J; Pierce, Aaron; Watson, Scott ^[1]

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1. Michigan Center for Theoretical Physics, University of Michigan, Ann Arbor, Michigan 48109 (United States)

Recently the PAMELA satellite-based experiment reported an excess of galactic positrons that could be a signal of annihilating dark matter. The PAMELA data may admit an interpretation as a signal from a winolike lightest supersymmetric particle of mass about 200 GeV, normalized to the local relic density, and annihilating mainly into W bosons. This possibility requires the current conventional estimate for the energy loss rate of positrons to be too large by roughly a factor of 5. Data from antiprotons and gamma rays also provide tension with this interpretation, but there are significant astrophysical uncertainties associated with their propagation. It is not unreasonable to take this well-motivated candidate seriously, at present, in part because it can be tested in several ways soon. The forthcoming PAMELA data on higher energy positrons and the Fermi Gamma-ray Space Telescope (formerly the Gamma-ray Large Area Space Telescope) data should provide important clues as to whether this scenario is correct. If correct, the wino interpretation implies a cosmological history in which the dark matter does not originate in thermal equilibrium.

• OSTI ID: 21259989
• Journal Information: Physical Review. D, Particles Fields, Journal Name: Physical Review. D, Particles Fields Journal Issue: 4 Vol. 79; ISSN PRVDAQ; ISSN 0556-2821
• Country of Publication: United States
• Language: English

Related Subjects

72 PHYSICS OF ELEMENTARY PARTICLES AND FIELDS
ANTIPROTONS
ASTROPHYSICS
DENSITY
ENERGY LOSSES
GAMMA DETECTION
GAMMA RADIATION
GEV RANGE 100-1000
MASS
NONLUMINOUS MATTER
POSITRONS
SATELLITES
SPACE
SPARTICLES
THERMAL EQUILIBRIUM
W MINUS BOSONS
W PLUS BOSONS