Sneutrino dark matter and the observed anomalies in cosmic rays

We revisit sneutrino dark matter in light of the recent results from the PAMELA and ATIC experiments. In the U(1)(B-L) extension of the minimal supersymmetric standard model the right-handed sneutrino is a natural candidate for thermal dark matter. Sneutrino annihilation at the present time can be considerably enhanced due to the exchange of the lightest field in the Higgs sector that breaks U(1)(B-L). The annihilation mainly produces taus (or muons) by the virtue of B - L charges. A sneutrino mass in the 1-2 TeV range provides a good fit to the PAMELA data and a reasonable fit to the ATIC data. Within this mass range the sneutrino-nucleon elastic scattering cross section is 10(-11)-10(-9) pb, which might be probed by upcoming and future direct detection experiments. In addition, if (at least) one of the neutrinos is dominantly a Dirac fermion, the sneutrino can provide a unified Picture of dark matter and inflation. (C) 2009 Elsevier B.V. All rights reserved.