ournal of C osmology and A stroparticle hysics J The Sommerfeld enhancement for dark matter with an excited state
ournal of C osmology and A stroparticle hysics J The Sommerfeld enhancement for dark matter with an excited state
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DOI：
10.1088/1475-7516/2010/02/028
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发表时间：
2009-10
影响因子：
6.4
通讯作者：
中科院分区：
文献类型：
--
作者：
我们提出了一个分析的索末菲增强暗物质湮灭的激发态的存在下，其中诱导增强的相互作用是纯粹的非对角，如在模型中的兴奋或非弹性的暗物质。我们导出了一个简单而精确的s波增强的半解析近似，只要基态和激发态之间的质量分裂不太大，这种近似是有效的，并讨论了大质量分裂时s波增强的截止。我们重现以前得到的结果在适当的限制，并表现出良好的协议与数值计算的增强。我们表明，激发态的存在下，导致一般较大的值的索末菲增强，较大的共振，并转移的共振较低的调解人群众。此外，在质量分裂的存在下，增强不再是速度的单调函数：动能接近激发更高状态所需的动能时的增强可以高达零速度时增强的两倍。
We present an analysis of the Sommerfeld enhancement to dark matter annihilation in the presence of an excited state, where the interaction inducing the enhancement is purely off-diagonal, such as in models of exciting or inelastic dark matter. We derive a simple and accurate semi-analytic approximation for the s-wave enhancement, which is valid provided the mass splitting between the ground and excited states is not too large, and discuss the cutoff of the enhancement for large mass splittings. We reproduce previously derived results in the appropriate limits, and demonstrate excellent agreement with numerical calculations of the enhancement. We show that the presence of an excited state leads to generically larger values of the Sommerfeld enhancement, larger resonances, and shifting of the resonances to lower mediator masses. Furthermore, in the presence of a mass splitting the enhancement is no longer a monotonic function of velocity: the enhancement where the kinetic energy is close to that required to excite the higher state can be up to twice as large as the enhancement at zero velocity.