A Running spectral index in supersymmetric dark-matter models with quasi-stable charged particles
Oct, 2004
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Abstract: (arXiv)
We show that charged-particles decaying in the early Universe can induce a scale-dependent or `running' spectral index in the small-scale linear and nonlinear matter power spectrum and discuss examples of this effect in minimal supersymmetric models in which the lightest neutralino is a viable cold-dark-matter candidate. We find configurations in which the neutralino relic density is set by coannihilations with a long-lived stau, and the late decay of staus partially suppresses the linear matter power spectrum. Nonlinear evolution on small scales then causes the modified linear power spectrum to evolve to a nonlinear power spectrum similar (but different in detail) to models parametrized by a constant running by redshifts of 2 to 4. Thus, Lyman- forest observations, which probe the matter power spectrum at these redshifts, might not discriminate between the two effects. However, a measurement of the angular power spectrum of primordial 21-cm radiation from redshift -- might distinguish between this charged-decay model and a primordial running spectral index. The direct production of a long-lived charged particle at future colliders is a dramatic prediction of this model.- 12.60.Jv
- 98.80.Es
- 98.80.Cq
- 95.35.+d
- dark matter
- supersymmetry
- charged particle: decay
- charged particle: lifetime
- cosmological model
- power spectrum
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