The origin of Dark Matter is one of the most pressing questions of physics. Despite overwhelming evidence of its existence since the first postulates around 100 years ago, its origin and interaction mechanism with visible matter have remained obscure. This has spurred a worldwide effort using a wide range of complementary techniques to probe Dark Matter models from the sub-eV to the multi-solar mass range with many interesting examples such as milli-charged particles, axion-like particles (ALPs), heavy neutral leptons (HNLs), Light Dark Matter (LDM) or Primordial Black Holes. Among these, LDM covers the eV to GeV range, defining a parameter space that is accessible in particle accelerator facilities.
NA64 is a fixed target experiment at the CERN SPS accelerator using complementary beams searching for Dark Sectors in the LDM mass range with the missing energy/momentum technique. In this seminar, I will focus on the program using the high intensity M2 muon beam line of the SPS. After the first results were obtained with $1.98\times10^{10}$ muons on target (MOT) collected in 2022, demonstrating the feasibility of the technique and published in Phys. Rev. Lett. 132, 211803 (2024) and Phys Rev. D 110, 112015 (2024), we have significantly improved the experimental setup and collected more data in 2023 and 2024. In this seminar, I will report the results based on the data collected in 2023 with $1.2\times10^{11}$ MOT. With a factor 6 more MOT than in 2022, I will present the experiment prospects in probing the parameter space of the well-motivated benchmark LDM models and other scenarios of New Physics below the electroweak scale.
Student Seminars