Logo
ScienceStack
Table of Contents
Fetching ...
Sign In

Constraints on WIMP Dark Matter from the High Energy PAMELA $\bar{p}/p$ data

F. Donato, D. Maurin, P. Brun, T. Delahaye, P. Salati

Abstract

A new calculation of the $\bar{p}/p$ ratio in cosmic rays is compared to the recent PAMELA data. The good match up to 100 GeV allows to set constraints on exotic contributions from thermal WIMP dark matter candidates. We derive stringent limits on possible enhancements of the WIMP \pbar flux: a $m_{\rm WIMP}$=100 GeV (1 TeV) signal cannot be increased by more than a factor 6 (40) without overrunning PAMELA data. Annihilation through the $W^+W^-$ channel is also inspected and cross-checked with $e^+/(e^-+e^+)$ data. This scenario is strongly disfavored as it fails to simultaneously reproduce positron and antiproton measurements.

Constraints on WIMP Dark Matter from the High Energy PAMELA $\bar{p}/p$ data

Abstract

A new calculation of the ratio in cosmic rays is compared to the recent PAMELA data. The good match up to 100 GeV allows to set constraints on exotic contributions from thermal WIMP dark matter candidates. We derive stringent limits on possible enhancements of the WIMP \pbar flux: a =100 GeV (1 TeV) signal cannot be increased by more than a factor 6 (40) without overrunning PAMELA data. Annihilation through the channel is also inspected and cross-checked with data. This scenario is strongly disfavored as it fails to simultaneously reproduce positron and antiproton measurements.

Paper Structure

This paper contains 1 equation, 3 figures.

Figures (3)

  • Figure 1: Left panel: IS antiproton flux for the B/C best fit model and two parameterizations of the production cross section. Right panel: propagation uncertainty envelopes of the IS $\overline{p}$$/p$ ratio for the same production cross sections as in the left panel. All data are demodulated using the force-field approximation: AMS 98 2002PhR...366..331A, IMAX 92 1996PhRvL..76.3057M, CAPRICE 94 1997ApJ...487..415B, WIZARD-MASS 91 1999ICRC....3...77B, CAPRICE 98 2001ApJ...561..787B, BESS93 1997ApJ...474..479M, BESS 95+97 2000PhRvL..84.1078O, BESS 98 2001APh....16..121M, BESS 99 and 2000 2002PhRvL..88e1101A, BESS 2002 2005ICRC....3...13H, BESS Polar 2008arXiv0805.1754A, WIZARD-MASS 1 1996ApJ...467L..33H, HEAT-$\bar{p}$2001PhRvL..87A1101B, and PAMELA PAMELA_PRL.
  • Figure 2: Upper limits on the enhancement factor to the primary $\overline{p}$ flux as a function of the WIMP mass, derived from a comparison with PAMELA high energy data. Each curve is labelled according to the corresponding PAMELA energy bin.
  • Figure 3: The fiducial case of a 1 TeV LSP annihilating into a $W^{+} W^{-}$ pair is featured. In the left panel, the positron signal which this DM species yields has been increased by a factor of 400, hence the solid curve and a marginal agreement with the PAMELA data. Positron fraction data are from HEAT 1997ApJ...482L.191B, AMS-01 Aguilar:2007yfAlcaraz:2000bf and PAMELA PAMELA_frac. If the so--called Sommerfeld effect Hisano:2003ec is invoked to explain such a large enhancement of the annihilation cross section, the same boost applies to antiprotons and leads to an unacceptable distortion of their spectrum as indicated by the red solid line of the right panel.