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Updated: Apr 15, 2026

Setting Limits on Supersymmetry Using Simplified Models
Published on: November 15, 2013
The extent of the stop coannihilation strip
John Ellis1, Keith A Olive2, Jiaming Zheng3
1Theoretical Particle Physics and Cosmology Group, Department of Physics, King's College London, London, WC2R 2LS UK ; Theory Division, CERN, 1211 Geneva 23, Switzerland.
Abstract:
Many supersymmetric models such as the constrained minimal supersymmetric extension of the Standard Model (CMSSM) feature a strip in parameter space where the lightest neutralino [Formula: see text] is identified as the lightest supersymmetric particle, the lighter stop squark [Formula: see text] is the next-to-lightest supersymmetric particle (NLSP), and the relic [Formula: see text] cold dark matter density is brought into the range allowed by astrophysics and cosmology by coannihilation with the lighter stop squark [Formula: see text] NLSP. We calculate the stop coannihilation strip in the CMSSM, incorporating Sommerfeld enhancement effects, and we explore the relevant phenomenological constraints and phenomenological signatures. In particular, we show that the [Formula: see text] may weigh several TeV, and its lifetime may be in the nanosecond range, features that are more general than the specific CMSSM scenarios that we study in this paper.
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