弱相互作用大质量粒子（Weakly Interactive Massive Particles，WIMPs）是冷暗物质（Cold Dark Matter，CDM）中研究最多的候选粒子。在最小宇宙学模型的框架下，普朗克合作组对宇宙微波背景辐射的详细测量将标度后的CDM遗迹密度修正为$Ω_{c}h^2=0.1193\pm0.0014$，误差小于1.5%。为了充分利用这种观测精度，理论计算应该有一个相当或更小的误差。本文利用最近的格点量子色动力学计算改进了对热等离子体的描述。这影响了预测的“热WIMP”的残余密度，这些残余密度曾经与标准模型粒子处于化学平衡。对于WIMP质量在3和15 GeV之间，QCD效应是最重要的，我们的预测不同于早期的结果高达9%（12%）的纯S波（P波）湮灭。我们使用这些结果来计算热平均的WIMP湮灭截面，再现正确的CDM遗物密度，WIMP质量在0.1 GeV和10 TeV之间。
英文摘要：
Weakly Interactive Massive Particles (WIMPs) are the most widely studied candidate particles forming the cold dark matter (CDM) whose existence can be inferred from a wealth of astrophysical and cosmological observations. In the framework of the minimal cosmological model detailed measurements on the cosmic microwave background by the PLANCK collaboration fix the scaled CDM relic density to $Ω_{c}h^2=0.1193\pm0.0014$, with an error of less than 1.5%. In order to fully exploit this observational precision, theoretical calculations should have a comparable or smaller error. In this paper we use recent lattice QCD calculations to improve the description of the thermal plasma. This affects the predicted relic density of "thermal WIMPs", which once were in chemical equilibrium with Standard Model particles. For WIMP masses between 3 and 15 GeV, where QCD effects are most important, our predictions differ from earlier results by up to 9% (12%) for pure S-wave (P-wave) annihilation. We use these results to compute the thermally averaged WIMP annihilation cross section that reproduces the correct CDM relic density, for WIMP masses between 0.1 GeV and 10 TeV.
We explore the simplest viable dark matter model with a real singlet scalar, vector-like singlet and doublet fermions. The Yukawa couplings associated with the fermion sector play a crucial role in getting the current relic density through Freeze-in and Freeze-out mechanism. We discuss the constraints from the recent muon anomalous magnetic moment experimental data and relic density. We also perform the collider analysis for the FIMP dark matter in the context of 14 TeV LHC experiments with the MATHUSLA100/200 detector. Our analysis shows that one can get enough events $>3$ for heavy charged f…
Precise Relic WIMP Abundance and its Impact on Searches for Dark Matter Annihilation
如果暗物质（DM）是一种弱相互作用大质量粒子（WIMP），是早期宇宙的热遗迹，那么它的总自湮灭截面可以通过它现在的质量密度来揭示。一般的WIMP的正则热平均截面通常表示为3*10^-26 cm ^3 s ^-1，不确定性没有具体说明，并且被认为与WIMP的质量无关。最近对DM湮没产物的搜索已经达到了排除100%分支比的正则截面的灵敏度，以确定最终状态和小WIMP质量。最终目标是探测所有运动学上允许的最终状态作为质量的函数，如果所有状态都被充分排除，则为WIMP质量设置下限。由于最近在直接和间接搜索中对轻WIMP的暗示，探测低质量区域的动机进一步增强。我们重新审视了一个通用的WIMP的热遗迹丰度计算，并表明所需的截面可以精确计算。当质量低于10 GeV时，它随质量变化很大，在质量约为0.3 GeV时达到最大值5.2*10^-26 cm ^3 s ^-1，当质量高于10 GeV时，它为2.2*10^-26 cm ^3 s ^-1，质量依赖性很弱。这些结果，显着不同的典型值，并没有考虑到在搜索湮灭产品从通用WIMPs，有一个显着的影响，从费米-LAT和WMAP+ACT目前的限制的解释。
Sterile neutrinos coupling only to third-generation fermions are attractive dark matter candidates. In an EFT approach we demonstrate that they can generate the observed relic density without violating constraints from direct and indirect detection. Such an EFT represents a gauged third-generation $B-L$ model, as well as third-generation scalar or vector leptoquarks. LHC measurements naturally distinguish the different underlying models.
We study a simple dark matter model given by two interacting real singlet scalars, with only one of them coupled to the Higgs. The model therefore presents a minimal assisted-freeze-out framework: both scalars contribute to the dark matter relic density, but only one of them takes part in the elastic scattering with nuclei. This reduces the expected interaction rate in direct detection experiments in such a way that the model in some regions of the parameter space may evade XENON1T constraints. We explore the model under theoretical (perturbativity, stability potential and unitarity) and exper…
We discuss the extent to which models of Weakly Interacting Massive Particle (WIMP) Dark Matter (DM) at and above the electroweak scale can be probed conclusively in future high energy and astroparticle physics experiments. We consider simplified models with bino-like dark matter and slepton-like coannihilation partners, and find that perturbative models yield the observed relic abundance up to at least 10 TeV. We emphasise that coannihilation can either increase or decrease the dark matter relic abundance. We compute the sensitivity of direct detection experiments to DM-nucleus scattering, co…
Electroweak Symmetry Breaking (EWSB) is known to produce a massive universe that we live in. However, it may also provide an important boundary for freeze-in or freeze-out of dark matter (DM) connected to Standard Model via Higgs portal as processes contributing to DM relic differ across the boundary. We explore such possibilities in a two-component DM framework, where a massive $U(1)_X$ gauge boson DM freezes-in and a scalar singlet DM freezes-out, that inherits the effect of EWSB for both the cases in a correlated way. Amongst different possibilities, we study two sample cases; first when on…
A dark matter (DM) having feeble interaction with the visible sector can thermalise via substantial interaction with a Weakly Interacting Massive Particle (WIMP). Such DM candidates are categorised as pseudo-FIMP (pFIMP). pFIMP can provide both direct and indirect search prospects via WIMP loop. This work focuses into such possibilities. We provide all such one loop graphs involving scalar, fermion and vector boson particles via which pFIMP can interact with the Standard Model assuming both of them are stabilised via $\mathbb{Z}_2\otimes \mathbb{Z}_2^{\prime}$ symmetries. We elaborate upon a m…
Producing an acceptable thermal relic abundance of dark matter with masses $\gg 10^2$ TeV is a challenge. We propose a novel mechanism where GeV-scale states establish a tiny thermal relic abundance for dark matter, which is later promoted to ultra massive status by a very light scalar. We refer to this dark matter as a THermal Ultra Massive Particle (THUMP). Direct detection of THUMPs can be naturally expected due to large scattering cross sections mediated by low mass states that couple THUMPs to the Standard Model. Our model generically leads to signals for the associated GeV-scale states a…
We consider multi-component dark matter in a model where one dark matter component is feebly interacting (FIMP) while the second is weakly interacting (WIMP). The model contains an inert scalar doublet and a complex scalar singlet and features a discrete $Z_4$ symmetry. We determine the parameter space that satisfies theoretical constraints, collider constraints, relic density as well as direct and indirect detection limits. We discuss the possibility to probe the model through collider and astrophysical searches. We find that it is possible that the FIMP forms the dominant DM component, in th…
Natural Phantom Crossing from Axion-WIMP Interactions
Laboratoire d’Annecy de Physique Théorique, CNRS–USMB（理论物理安纳西实验室，法国国家科学研究中心-萨瓦大学）；School of Physics, KIAS（韩国高等科学研究院物理学院）；Quantum Universe Center, KIAS（韩国高等科学研究院量子宇宙中心）；Department of Physics, LEPP, Cornell University（康奈尔大学应用和工程物理系）
Thermal freeze-out is a prominent example of dark matter (DM) production mechanism in the early Universe that can yield the correct relic density of stable weakly interacting massive particles (WIMPs). At the other end of the mass scale, many popular extensions of the Standard Model predict the existence of ultra-light scalar fields. These can be coupled to matter, preferentially in a universal and shift-symmetry-preserving way. We study the impact of such conformal and disformal couplings on the relic density of WIMPs, without introducing modifications to the thermal history of the Universe. …
