Neutralino Relic Density with a Cosmological Constant confronts Electroweak Precision Measurements

TL;DR

This paper examines how the relic density of the lightest supersymmetric particle aligns with cosmological data and electroweak measurements, constraining supersymmetry parameters and sparticle masses.

Contribution

It provides a combined analysis of cosmological and electroweak data to constrain supersymmetric models and sparticle mass ranges.

Findings

Cosmological data favors low supersymmetry breaking scales.

Electroweak measurements favor higher supersymmetry breaking scales.

Allowed parameter space includes specific ranges for m_0 and M_{1/2}.

Abstract

We discuss the relic density of the lightest of the supersymmetric particles ({\small LSP}) in view of new cosmological data, which favour the concept of an accelerating Universe with a non-vanishing cosmological constant. The new bound on the Cold Dark Matter density, $\Omega_{\mathrm{CDM}} h_0^2 \lesssim 0.22$, puts stringent constraints on supersymmetry preferring low supersymmetry breaking scales, in sharp contrast to electroweak precision measurements favouring large supersymmetry breaking scales. Supersymmetric predictions are in agreement with cosmological data and electroweak precision data in the window of the parameter space: $m_0<200\GeV$, $300\GeV<M_{1/2}<400\GeV$, putting bounds on sparticle masses, which may be evaded if $m_{LSP} <m_{{\tilde{\tau}}_R} \lesssim 1.2 m_{LSP}$.