Change search
ReferencesLink to record
Permanent link

Direct link
Fermi/LAT observations of dwarf galaxies highly constrain a dark matter interpretation of excess positrons seen in AMS-02, HEAT, and PAMELA
KTH, Centres, Nordic Institute for Theoretical Physics NORDITA.
2016 (English)In: Journal of Cosmology and Astroparticle Physics, ISSN 1475-7516, E-ISSN 1475-7516, Vol. 2016, no 3, 033Article in journal (Refereed) PublishedText
Abstract [en]

It is shown that a Weakly Interacting Massive dark matter Particle (WIMP) interpretation for the positron excess observed in a variety of experiments, HEAT, PAMELA, and AMS-02, is highly constrained by the Fermi/LAT observations of dwarf galaxies. In particular, this paper examines the annihilation channels that best fit the current AMS-02 data (Boudaud et al., 2014), specifically focusing on channels and parameter space not previously explored by the Fermi/LAT collaboration. The Fermi satellite has surveyed the γ-ray sky, and its observations of dwarf satellites are used to place strong bounds on the annihilation of WIMPs into a variety of channels. For the single channel case, we find that dark matter annihilation into {b,e+e-, μ+μ-, τ+τ-,4-e or 4-τ } is ruled out as an explanation of the AMS positron excess (here b quarks are a proxy for all quarks, gauge and Higgs bosons). In addition, we find that the Fermi/LAT 2σ upper limits, assuming the best-fit AMS-02 branching ratios, exclude multichannel combinations into b and leptons. The tension between the results might relax if the branching ratios are allowed to deviate from their best-fit values, though a substantial change would be required. Of all the channels we considered, the only viable channel that survives the Fermi/LAT constraint and produces a good fit to the AMS-02 data is annihilation (via a mediator) to 4-μ, or mainly to 4-μ in the case of multichannel combinations.

Place, publisher, year, edition, pages
Institute of Physics Publishing (IOPP), 2016. Vol. 2016, no 3, 033
Keyword [en]
cosmic ray experiments, dark matter experiments, gamma ray experiments
National Category
Physical Sciences
URN: urn:nbn:se:kth:diva-187220DOI: 10.1088/1475-7516/2016/03/033ScopusID: 2-s2.0-84961737527OAI: diva2:932350

QC 20160601

Available from: 2016-06-01 Created: 2016-05-18 Last updated: 2016-06-03Bibliographically approved

Open Access in DiVA

No full text

Other links

Publisher's full textScopus

Search in DiVA

By author/editor
Savage, Christopher
By organisation
Nordic Institute for Theoretical Physics NORDITA
In the same journal
Journal of Cosmology and Astroparticle Physics
Physical Sciences

Search outside of DiVA

GoogleGoogle Scholar
The number of downloads is the sum of all downloads of full texts. It may include eg previous versions that are now no longer available

Altmetric score

Total: 3 hits
ReferencesLink to record
Permanent link

Direct link