Ellis John, Olive Keith A, Zheng Jiaming
Theoretical Particle Physics and Cosmology Group, Department of Physics, King's College London, London, WC2R 2LS UK ; Theory Division, CERN, 1211 Geneva 23, Switzerland.
School of Physics and Astronomy, University of Minnesota, Minneapolis, MN 55455 USA ; William I. Fine Theoretical Physics Institute, School of Physics and Astronomy, University of Minnesota, Minneapolis, MN 55455 USA.
Eur Phys J C Part Fields. 2014;74(7):2947. doi: 10.1140/epjc/s10052-014-2947-7. Epub 2014 Jul 9.
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.
许多超对称模型，如标准模型的约束最小超对称扩展（CMSSM），在参数空间中有一个条带区域，其中最轻的中性伴随子[公式：见正文]被认定为最轻的超对称粒子，较轻的顶夸克超对称伙伴[公式：见正文]是次最轻的超对称粒子（NLSP），并且遗迹[公式：见正文]冷暗物质密度通过与较轻的顶夸克超对称伙伴[公式：见正文]NLSP的共湮灭被带入天体物理学和宇宙学所允许的范围。我们在CMSSM中计算顶夸克超对称伙伴共湮灭条带，纳入索末菲增强效应，并探索相关的现象学约束和现象学特征。特别是，我们表明[公式：见正文]可能重达数太电子伏特，其寿命可能在纳秒范围内，这些特征比我们在本文中研究的特定CMSSM情景更具普遍性。
