论文标题
在暗物质中散射与禁忌腐烂冻结
Scattering versus Forbidden Decay in Dark Matter Freeze-in
论文作者
论文摘要
通常认为，相对于两体衰减，两体散射被高阶弱耦合所抑制。我们表明，当禁止衰变在热等离子体中产生重粒子时，这并不总是存在，在热等离子度中，散射与衰减具有相同的耦合顺序。我们发现，禁忌衰变与相同阶散射之间存在一个简单而密切的关系。为了说明这一点，我们考虑通过轻标量调解器冻结重型暗物质的生产。我们指出的是，当使用Boltzmann（量子）统计数据时，禁止的衰减在5 $ \％$ \％$ -24 $ \％$（10 $ \％$ \％$ \％$ -39 \％$）的情况下，具有较弱的热耦合，而散射频道的贡献则比几个较小的量子均更大的量相结合。在其他血浆诱导的过程中，散射与禁止衰变之间的这种相对效应也可能存在，例如右手中微子暗物质的纯热产生，或诱导中的Lepton不对称性。
It is generically believed that the two-body scattering is suppressed by higher-order weak couplings with respect to the two-body decay. We show that this does not always hold when a heavy particle is produced by forbidden decay in a thermal plasma, where the scattering shares the same order of couplings with the decay. We find that there is a simple and close relation between the forbidden decay and the same-order scattering. To illustrate this point, we consider freeze-in production of heavy dark matter via a light scalar mediator. We point out that, when the Boltzmann (quantum) statistics is used, the forbidden decay can contribute to the dark matter relic density at 5$\%$-24$\%$ (10$\%$-$39\%$) with a weak thermal coupling, while the contribution from the scattering channel can be several orders of magnitude larger than from the forbidden decay if the thermal coupling is much smaller. Such a relative effect between the scattering and the forbidden decay could also exist in other plasma-induced processes, such as the purely thermal generation of the right-handed neutrino dark matter, or of the lepton asymmetry in leptogenesis.
