Constraints on WIMP Dark Matter from the High Energy PAMELAp¯/pData

A new calculation of the $\overline{p}/p$ ratio in cosmic rays is compared to the recent PAMELA data. The good match up to 100 GeV allows us to set constraints on exotic contributions from thermal weakly interacting massive particle (WIMP) dark matter candidates. We derive stringent limits on possible enhancements of the WIMP $\overline{p}$ flux: a $m_{\mathrm{WIMP}}=100\mathrm{GeV}$ (1 TeV) signal cannot be increased by more than a factor of 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.