Neutralino relic density in a Universe with a non-vanishing cosmological constant

TL;DR

This paper examines how a non-zero cosmological constant influences the relic density of the lightest supersymmetric particles within the CMSSM, considering recent cosmological and astrophysical data.

Contribution

It analyzes the impact of a non-vanishing cosmological constant on supersymmetric relic density calculations and explores parameter regions that satisfy observational constraints.

Findings

Constraints on supersymmetry breaking scale from cosmological data

Large tan β and positive μ can evade certain limits

Degeneracy between LSP and next-to-lightest supersymmetric particle

Abstract

We discuss the relic density of the lightest of the supersymmetric particles in view of new cosmological data, which favour the concept of an accelerating Universe with a non-vanishing cosmological constant. Recent astrophysical observations provide us with very precise values of the relevant cosmological parameters. Certain of these parameters have direct implications on particle physics, e.g., the value of matter density, which in conjunction with electroweak precision data put severe constraints on the supersymmetry breaking scale. In the context of the Constrained Minimal Supersymmetric Standard Model (CMSSM) such limits read as: $M_{1/2} \simeq 300 \GeV - 340 \GeV$, $m_0 \simeq 80 \GeV - 130 \GeV$. Within the context of the CMSSM a way to avoid these constraints is either to go to the large $\tan \beta$ and $\mu > 0$ region, or make ${\tilde \tau}_R$, the next to lightest supersymmetric particle (LSP), be almost degenerate in mass with LSP.