Multistate dark matter ( DM ) models with small mass splittings and couplings to light hidden sector bosons have been proposed as an explanation for the PAMELA/Fermi/H.E.S.S .
high-energy lepton excesses .
We investigate this proposal over a wide range of DM density profiles , in the framework of concrete models with doublet or triplet dark matter and a hidden SU ( 2 ) gauge sector that mixes with standard model hypercharge .
The gauge coupling is bounded from below by the DM relic density , and the Sommerfeld enhancement factor is explicitly computable for given values of the DM and gauge boson masses M , \mu and the ( largest ) dark matter mass splitting \delta M _ { 12 } .
Sommerfeld enhancement is stronger at the galactic center than near the Sun because of the radial dependence of the DM velocity profile , which strengthens the inverse Compton ( IC ) gamma ray constraints relative to usual assumptions .
We find that the PAMELA/Fermi/H.E.S.S .
lepton excesses are marginally compatible with the model predictions , and with CMB and Fermi gamma ray constraints , for M \cong 800 GeV , \mu \mbox { \raisebox { -2.58 pt } { ~ { } $ \stackrel { < } { \sim } $~ { } } } 200 MeV , and a dark matter profile with noncuspy Einasto parameters \alpha \mbox { \raisebox { -2.58 pt } { ~ { } $ \stackrel { > } { \sim } $~ { } } } 0.20 , r _ { s } \sim 30 kpc .
We also find that the annihilating DM must provide only a subdominant ( \mbox { \raisebox { -2.58 pt } { ~ { } $ \stackrel { < } { \sim } $~ { } } } 0.4 ) component of the total DM mass density , since otherwise the boost factor due to Sommerfeld enhancement is too large .