1205.5826 (Nobuchika Okada)

SuperWIMP dark matter and 125 GeV Higgs boson in the minimal GMSB    [PDF]

Nobuchika Okada

Recently, both the ATLAS and CMS experiments have observed an excess of events that could be the first evidence for a 125 GeV Higgs boson. We investigate an implication of the CP-even Higgs boson with mass around 125 GeV in the context of the minimal gauge mediated supersymmetry breaking (mGMSB). In mGMSB, gravitino is the lightest sparticle (LSP) and hence the dark matter candidate. We consider the so-called superWIMP scenario where the dark matter gravitino is non-thermally produced by the decay of the next-to-LSP (NLSP) bino-like neutralino after its freeze-out. For a given $\tan \beta$ and the number of the messengers ($N_m$) fixed, we find that the rest of the mGMSB parameters, the SUSY breaking parameter and the messenger scale, are completely fixed by the conditions of simultaneously realizing the observed dark matter abundance and the 125 GeV Higgs boson mass, leading to the NLSP neutralino mass around 1.5-2 TeV and the gravitino mass around 3-7 GeV, depending on the values of $\tan \beta$ and $N_m$. The lifetime of the NLSP is found to be shorter than 1 sec, so that the success of the big bang nucleosynthesis remains intact. The non-thermally produced gravitino behaves as the warm dark matter with the free-streaming scale found to be $\lambda_{\rm FS} \simeq 0.1$ Mpc, whose value is reasonable for observations of the power spectrum on both large and sub-galactic scales in the Universe.

View original: http://arxiv.org/abs/1205.5826