SENSEI: Direct-Detection Results on sub-GeV Dark Matter from a New Skipper-CCD

Single-electron and single-photon sensitivity with a silicon Skipper CCD

We have developed a non-destructive readout system that uses a floating-gate amplifier on a thick, fully depleted charge coupled device (CCD) to achieve ultra-low readout noise of 0.068 e- rms/pix. This is the first time that discrete sub-electron readout noise has been achieved reproducibly over millions of pixels on a stable, large-area detector. This allows the precise counting of the number of electrons in each pixel, ranging from pixels with 0 electrons to more than 1500 electrons. The resulting CCD detector is thus an ultra-sensitive calorimeter. It is also capable of counting single pho…

The low-energy spectrum in DAMIC at SNOLAB

The DAMIC experiment employs large-area, thick charge-coupled devices (CCDs) to search for the interactions of low-mass dark matter particles in the galactic halo with silicon atoms in the CCD target. From 2017 to 2019, DAMIC collected data with a seven-CCD array (40-gram target) installed in the SNOLAB underground laboratory. We report dark-matter search results, including a conspicuous excess of events above the background model below 200 eV$_{\rm ee}$, whose origin remains unknown. We present details of the published spectral analysis, and update on the deployment of skipper CCDs to perform…

SENSEI在SNOLAB：单电子事件率及对暗物质的意义

SENSEI at SNOLAB: Single-Electron Event Rate and Implications for Dark Matter

SENSEI实验在SNOLAB取得单电子事件率新成果，通过升级设备提升性能，为暗物质研究提供关键数据。

Direct Detection of Strongly Interacting Sub-GeV Dark Matter via Electron Recoils

We consider direct-detection searches for sub-GeV dark matter via electron scatterings in the presence of large interactions between dark and ordinary matter. Scatterings both on electrons and nuclei in the Earth's crust, atmosphere, and shielding material attenuate the expected local dark matter flux at a terrestrial detector, so that such experiments lose sensitivity to dark matter above some critical cross section. We study various models, including dark matter interacting with a heavy and ultralight dark photon, through an electric dipole moment, and exclusively with electrons. For a dark-…

DAMIC-M低本底腔室

The DAMIC-M Low Background Chamber

本文介绍DAMIC-M暗物质实验的低本底腔室（LBC）原型机，该装置自2022年起在法国莫达讷地下实验室运行，用于表征skipper CCD、研究暗电流、测量材料放射性纯度并测试各子系统，为千克级轻暗物质探测奠定基础。

Sources of Low-Energy Events in Low-Threshold Dark Matter and Neutrino Detectors

We discuss several low-energy backgrounds to sub-GeV dark matter searches, which arise from high-energy particles of cosmic or radioactive origin that interact with detector materials. We focus in particular on Cherenkov radiation, transition radiation, and luminescence or phonons from electron-hole pair recombination, and show that these processes are an important source of backgrounds at both current and planned detectors. We perform detailed analyses of these backgrounds at several existing and proposed experiments based on a wide variety of detection strategies and levels of shielding. We …

将量子点探测器作为暗物质相互作用的条形码

Towards Quantum-Dot Detectors as Barcodes for Dark Matter Interactions

该研究提出用量子点探测器阵列的响应作为“条形码”，通过从头计算暗物质与量子点束缚电子的散射，可区分暗物质相互作用算子和媒介子类型，并量化了其区分能力与读出噪声、曝光量的关系。

利用DAMIC-M探测隐藏区暗物质的基准模型

Probing Benchmark Models of Hidden-Sector Dark Matter with DAMIC-M

本研究利用DAMIC-M原型探测器开展亚GeV暗物质搜寻，通过更低本底、更高曝光的数据，对1-1000 MeV/$c^2$质量范围的电子相互作用暗物质施加了严格约束，排除了部分隐藏区暗物质的理论基准场景。