NEWS-G, Light dark matter search with a Spherical Proportional Counter, First results and Future prospects

Search for light dark matter with NEWS-G

The NEWS-G collaboration is searching for light dark matter candidates using a spherical proportional counter. Light gases, such as hydrogen, helium, and neon, are used as targets, providing access in the 0.1-10 GeV mass range. First results obtained with SEDINE, a 60 cm in diameter detector, in the Underground Laboratory of Modane yielded a 90% confidence level upper limit of 4.4x 10^{37} cm^2 on the nucleon-dark matter interaction cross-section for a candidate with 0.5 GeV mass. Recent developments in several aspects of the detector instrumentation are presented, along with the construction …

Recent advancements of the NEWS-G experiment

NEWS-G (New Experiments With Spheres-Gas) is an experiment aiming to shine a light on the dark matter conundrum with a novel gaseous detector, the spherical proportional counter. It uses light gases, such as hydrogen, helium, and neon, as targets to expand dark matter searches to the sub-GeV/c$^{2}$ mass region. NEWS-G produced its first results with a 60 cm in diameter detector installed at LSM (France), excluding at 90% C.L. cross-sections above $4.4\cdot{10}^{37}$ cm$^{2}$ for dark matter candidates of 0.5 GeV/c$^{2}$ mass. Currently, a 140 cm in diameter detector is being built at LSM and …

Status and prospects for BESIII

In this paper the status and prospects for BESIII is presented.The BEPCII machine is in good status and recently reached its highest luminosity of 7.08*10^32cm^-2s^-1. The BESIII detectors have been running stably since 2009. Upgrade plans for its sub-detectors have been proposed and the upgrade is undergoing. The major upgrade comes from the drift chamber and the time of of flight counter. The other sub-detectors show good status and no upgrade are needed. Given the current status and upgrade plan of the BESIII detectors, it's foreseen that the BESIII is able to work for 8 to 10 years from no…

MEG II experiment status and prospect

The MEG II experiment at Paul Scherrer Institute (PSI) in Switzerland aims to achieve a sensitivity of $6\times10^{-14}$ on the charged lepton flavor violating decay $μ^+\to e^+γ$. The current upper limit on this decay is $4.2\times10^{-13}$ at 90% Confidence Level (CL), set by the first phase of MEG. This result was achieved using the PSI muon beam at a reduced intensity, $3\times10^7~μ^+/$s, to keep the background at a manageable level. The upgraded detectors in MEG~II can cope with a higher intensity, thus the experiment is expected to run at a $7\times10^7~μ^+/$s intensity. The new low mas…

利用甲烷靶在莫达讷地下实验室用NEWS-G搜寻轻暗物质

Search for Light Dark Matter with NEWS-G at the Laboratoire Souterrain de Modane Using a Methane Target

NEWS-G实验利用莫达讷地下实验室中直径135 cm、以114 g甲烷为靶的球形比例计数器进行10天运行，在0.17–1.2 GeV/c²质量范围内给出轻暗物质自旋相关耦合的新限制，0.76 GeV/c²处90%置信水平截面上限为30.9 pb。

Copper electroplating for background suppression in the NEWS-G experiment

New Experiments with Spheres-Gas (NEWS-G) is a dark matter direct detection experiment that will operate at SNOLAB (Canada). Similar to other rare-event searches, the materials used in the detector construction are subject to stringent radiopurity requirements. The detector features a 140-cm diameter proportional counter comprising two hemispheres made from commercially sourced 99.99% pure copper. Such copper is widely used in rare-event searches because it is readily available, there are no long-lived Cu radioisotopes, and levels of non-Cu radiocontaminants are generally low. However, measure…