PAMELA/ATIC anomaly from the meta-stable extra dark matter component and the leptophilic Yukawa interaction

Understand

We present a supersymmetric model with two dark matter (DM) components explaining the galactic positron excess observed by PAMELA/HEAT and ATIC/PPB-BETS: One is the conventional (bino-like) lightest supersymmetric particle (LSP) \chi, and the other is a TeV scale meta-stable neutral singlet N_D, which is a Dirac fermion (N,N^c).

• In this model, N_D decays dominantly into \chi e^+e^- through an R parity preserving dimension 6 operator with the life time \tau_N\sim 10^{26} sec.
• We introduce a pair of vector-like superheavy SU(2) lepton doublets (L,L^c) and lepton singlets (E,E^c).
• The dimension 6 operator leading to the N_D decay is generated from the leptophilic Yukawa interactions by W\supset Ne^cE+Lh_dE^c+m_{3/2}l_1L^c with the dimensionless couplings of order unity, and the gauge interaction by {\cal L}\supset \sqrt{2} g'\tilde{e}^{c*}e^c\chi + h.c.