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Towards An Accurate Calculation of the Neutralino Relic Density

Takeshi Nihei·Leszek Roszkowski·Roberto Ruiz de Austri
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Abstract

We compute the neutralino relic density in the minimal supersymmetric standard model by using exact expressions for the neutralino annihilation cross section into all tree-level final states, including all contributions and interference terms. We find that several final states may give comparable contributions to the relic density, which illustrates the importance of performing a complete calculation. We compare the exact results with those of the usual expansion method and demonstrate a sizeable discrepancy (of more than 10%) over a significant range of the neutralino mass of up to several tens of GeV which is caused by the presence of resonances and new final-state thresholds. We perform several related checks and comparisons. In particular, we find that the often employed approximate iterative procedure of computing the neutralino freeze-out temperature gives generally very accurate results, except when the expansion method is used near resonances and thresholds.

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Takeshi Nihei, Leszek Roszkowski, Roberto Ruiz de Austri. 2001-02-25. Towards An Accurate Calculation of the Neutralino Relic Density. https://doi.org/10.1088/1126-6708%2F2001%2F05%2F063

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