Two dark matter components in N_{DM}MSSM and dark matter extension of the minimal supersymmetric standard model and the high energy positron spectrum in PAMELA/HEAT data

Abstract

We present the dark matter (DM) extension (by N) of the minimal supersymmetric standard model to give the recent trend of the high energy positron spectrum of the PAMELA/HEAT experiments. If the trend survives by future experiments, the MSSM needs to be extended. Here, we minimally extend the MSSM with one more DM component N together with a heavy lepton E, and introduce the coupling e_R E_R^c N_R. This coupling naturally appears in the flipped SU(5) GUT models. This N_{DM}MSSM contains the discrete symmetry Z_6, and for some parameter ranges there result two DM components. For the MSSM fields, the conventional R-parity, which is a subgroup of Z_6, is preserved. We also present the needed parameter ranges of these additional particles.

Figures (4)

• Figure 1: The bino-like neutralino annihilation. (a) The bullet carries an $SU(2)_W$ quantum number. (b) Here, the bullet can carry angular momentum 1. The helicities of electrons and positrons are shown by thick arrow lines.
• Figure 2: A typical diagram for a bibo $\chi$ annihilation. $N_RN_R^c$ annihilation to $e^+e^-$ is also possible.
• Figure 3: In the $M_{\chi}-m_E$ plane, the kinematically allowed mass region is shaded for a typical mass value of $m_N$. For $M_{\tilde{N}}>2m_N$, $\tilde{N}\to NN$ decay is possible. For $M_\chi>3m_N$, the decay $\chi\to 3N^ce^+e^-$ is possible.
• Figure 4: The positron fraction from our model with $M_\chi=200$ GeV, $m_N=80$ GeV, $m_E=200$ GeV, $M_{\tilde{E}}= 400$ GeV and $M_{\tilde{e}}=220$ GeV (thick green line) and $B=7$. $M_{\tilde{e}}$ for 250 GeV (blue dash line) and 280 GeV (brown dash line) are also shown. The pink band is the positron fraction coming from $\chi N$ and $NN$ annihilations and the green band is this positron excess on top of the astrophysical background (the thick darkblue dash line) Delahaye08Baltz98. The width of the band shows the uncertainty from the positron propagation model. The PAMELA data are the red dots PAMELAexp, and the various small dots represent the observed positron cosmic ray data Grimani02AMS01CAPRICE94HEAT95.