在SuperCDMS中通过轫致辐射和Migdal效应搜寻低质量暗物质

A Search for Low-mass Dark Matter via Bremsstrahlung Radiation and the Migdal Effect in SuperCDMS

In this paper, we present a re-analysis of SuperCDMS data using a profile likelihood approach to search for sub-GeV dark matter particles (DM) through two inelastic scattering channels: bremsstrahlung radiation and the Migdal effect. By considering possible inelastic scattering channels, experimental sensitivity can be extended to DM masses that would otherwise be undetectable through the DM-nucleon elastic scattering channel, given the energy threshold of current experiments. We exclude DM masses down to $220~\textrm{MeV}/c^2$ at $2.7 \times 10^{-30}~\textrm{cm}^2$ via the bremsstrahlung chan…

The Migdal effect in semiconductors

When a nucleus in an atom undergoes a collision, there is a small probability to inelastically excite an electron as a result of the Migdal effect. In this Letter, we present a first complete derivation of the Migdal effect from dark matter-nucleus scattering in semiconductors, which also accounts for multiphonon production. The rate can be expressed in terms of the energy loss function of the material, which we calculate with density functional theory (DFT) methods. Because of the smaller gap for electron excitations, we find that the rate for the Migdal effect is much higher in semiconductor…

Migdal effect and photon Bremsstrahlung: improving the sensitivity to light dark matter of liquid argon experiments

The search for dark matter weakly interacting massive particles with noble liquids has probed masses down and below a GeV/c^2. The ultimate limit is represented by the experimental threshold on the energy transfer to the nuclear recoil. Currently, the experimental sensitivity has reached a threshold equivalent to a few ionization electrons. In these conditions, the contribution of a Bremsstrahlung photon or a so-called Migdal electron due to the sudden acceleration of a nucleus after a collision might be sizable. In the present work, we use a Bayesian approach to study how these effects can be…

利用 Migdal 效应将 WIMP–夸克和 WIMP–胶子有效相互作用的直接探测限制扩展至低质量区

Low-mass extension of direct detection bounds on WIMP-quark and WIMP-gluon effective interactions using the Migdal effect

本文利用 Migdal 效应并结合 XENON1T 等四项实验数据，将 WIMP–夸克/胶子 EFT 高至维数 7 算符的直接探测限制扩展到约 20 MeV，同时指出高维算符约束的 EFT 自洽性问题。

利用米格达尔效应得到的非弹性散射WIMP有效模型的低质量约束

Low-mass constraints on WIMP effective models of inelastic scattering using the Migdal effect

本研究利用Migdal效应拓展了非弹性散射WIMP有效场论耦合的低质量约束，系统对比了Migdal效应与核反冲搜索在$m_χ-δ$参数空间的约束，明确了不同实验在不同参数区间的约束强度差异。

低Z靶Landau-Pomeranchuk-Migdal效应的实验研究

Experimental investigation of the Landau-Pomeranchuk-Migdal effect in low-Z targets

在CERN NA 63合作中，我们通过测量20和178 GeV电子在100 MeV - 4 GeV范围内的光子发射，在低密度聚乙烯（LDPE），C，Al，Ti，Fe，Cu，Mo的目标中，以及作为参考目标的Ta，解决了Landau-Pomeranchuk-Migdal（LPM）效应的常用Migdal公式的潜在不足问题。对于每个目标和能量，基于非相干韧致辐射的LPM抑制的模拟值之间的比较示出，考虑到多光子效应。对于这些目标和能量，我们发现，Migdal的理论公式是足够的精度优于约5%，无论目标物质。