LHC and ILC data and the Early Universe properties

Nuovo Cimento della Societa Italiana di Fisica C 02/2010; 33(2). DOI: 10.1393/ncc/i2010-10593-1
Source: arXiv


With the start-up of the LHC, we can hope to find evidences for new physics beyond the Standard Model, and particle candidates for dark matter. Determining the parameters of the full underlying theory will be a long process requiring the combination of LHC and ILC data, flavor physics constraints, and cosmological observations. However, the Very Early Universe properties, from which the relic particles originate, are poorly known, and the relic density calculation can be easily falsified by hidden processes. We consider supersymmetry and show that determining the underlying particle physics parameters will help understanding the Very Early Universe properties. Comment: 6 pages, 2 figures, contribution to the proceedings of the workshop "LC09: e+e- Physics at the TeV Scale and the Dark Matter Connection", Perugia, September 21 - 24, 2009, Italy. v2: reference added

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    • "The search for supersymmetry and its breaking, in addition to the direct searches at LEP, Bfactories , Tevatron and the Large Hadron Collider (LHC), is actively pursued using the WMAP limits on the relic density constraints. However the sensitivity of the lightest supersymmetric particle relic density calculation to the variation of the cosmological expansion rate before Big- Bang Nucleosynthesis (BBN), even if modest and with no consequences on the cosmological observations, can modify considerably the relic density, and therefore change the constraints on the supersymmetric parameter space [1] [2]. In the standard cosmology the dominant component before BBN is radiation, however energy density and entropy content can be modified. "
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    ABSTRACT: Anomaly mediation is a popular and well motivated supersymmetry breaking scenario. Different possible detailed realisations of this set-up are studied and actively searched for at colliders. Apart from limits coming from flavour, low energy physics and direct collider searches, these models are usually constrained by the requirement of reproducing the observations on dark matter density in the universe. We reanalyse these bounds and in particular we focus on the dark matter bounds both considering the standard cosmological model and alternative cosmological scenarios. These scenarios do not change the observable cosmology but relic dark matter density bounds strongly depend on them. We consider few benchmark points excluded by standard cosmology dark matter bounds and suggest that loosening the dark matter constraints is necessary in order to avoid a too strong (cosmological) model dependence in the limits that are obtained for these models. We also discuss briefly the implications for phenomenology and in particular at the Large Hadron Collider.
    Full-text · Article · Mar 2011 · Journal of High Energy Physics