Relic density of neutralino dark matter in the MSSM withCPviolation

Abstract

We calculate the relic density of dark matter in the MSSM with CP violation. We analyze various scenarios of neutralino annihilation: the cases of a b-ino, b-ino-W-ino and b-ino-Higgsino LSP, annihilation through Higgs, as well as sfermion coannihilation scenarios. Large phase effects are found-on the one hand, due to shifts in the masses; on the other hand, due to modifications of the couplings. Taking special care to disentangle the effects in masses and couplings, we demonstrate that the presence of CP phases can have a significant influence on the neutralino relic abundance. Typical variations in h 2 solely from modifications in the couplings are O (10%-100%), but can reach an order of magnitude in some cases.

ATLAS on-Z excess via gluino-Higgsino-singlino decay chains in the NMSSM

“…The overabundance is, however, avoided when the heavy Higgs masses are about twice of the mass of the singlino dark matter. Such a mass spectrum can be achieved by tuning the parameter A λ [50]. With this tuning, the singlino-like neutralino annihilates resonantly via the s-channel heavy Higgs boson exchange, which significantly enhances the annihilation cross section.…”

“…In addition, sizable κ can also enhance the annihilation cross section. It is because that contributions of diagrams of s-cannel a s boson exchange into fermions [53] and t-channelχ 0 1 exchange into h s + a s [50] become efficient when κ is sizable, where both a s and h s are the singlet-like scalar bosons. In fact, at the large λ benchmark point, the contribution of a processχ 0 1χ 0 1 → tt to the annihilation cross section is 79 %, andχ 0 1χ 0 1 → h 2 a 1 is 15 %, where a dominant decay channel of a 1 is tt.…”

Detecting the dark matter annihilation at the ground EAS detectors

“…The cosmological constraints on the supersymmetric (SUSY) parameter space have been extensively studied in the literature [3].…”

Top and bottom squarks decays under cosmological bounds

“…In the numerical calculations, although the SUSY parameters µ, M 1 , M 2 , and A f are in general complex, we assume that µ, M 2 , A t and A b are real, but M 1 and its phase ϕ U (1) take values on the WMAP-allowed bands given in Ref. [5]. These bands also satisfy the EDM bounds [7].…”

“…Recently, in the light of this cosmological constraint, an extensive analysis of the neutralino relic density in the presence of CP phases has been given by Bélanger et al. [5].…”