2924433 SzGeCERN 20250217092813.0 DOI SISSA 10.22323/1.476.0242 oai:cds.cern.ch:2924433 cerncds:FULLTEXT cerncds:CERN:FULLTEXT cerncds:CERN https://inspirehep.net/api/oai2d oai:inspirehep.net:2867763 2025-02-14T16:12:43Z 2025-02-15T05:02:59Z marcxml Inspire 2867763 eng Marini, Anna INFN, Genoa SISSA Dark Sector searches with electron and positron beams at NA64@CERN 2024 6 p SISSA Several astrophysical observations indicate that the majority of the mass of the Universe is made of a new type of matter, called Dark Matter, not interacting with light. DM may be composed of a dark sector of new particles, charged under a new U(1) gauge boson kinetically mixed with the ordinary photon, called dark photon. The NA64e experiment at CERN aims to produce and detect DS particles using a 100 GeV electron beam impinging on a thick active target (electromagnetic calorimeter). The detection of DS particles in NA64e occurs through the ``missing energy" technique. So far, NA64e sets the most competitive limits in the $1$ MeV $ < $ m$_\chi <$ $100$ MeV parametersspace, with an accumulated statistic of 9.37$\cdot 10^{11}$ electrons on target.In conjunction with the ERC-funded project POKER, from 2022 NA64e started collecting data also with positron beams, to exploit the DS production yield enhancement due to the positron resonant annihilation process. This work presents the latest results of the NA64e measurements, both with electron and positrons beams. CC-BY-NC-ND-4.0 SISSA https://creativecommons.org/licenses/by-nc-nd/4.0/ For annual report SzGeCERN Nuclear Physics - Experiment SzGeCERN Particle Physics - Experiment ARTICLE CERN CERN SPS NA64 NA64e Collaboration 242 PoS ICHEP2024 C24-07-17 2025 2714146 526476 http://cds.cern.ch/record/2924433/files/document.pdf Fulltext 13 2900723 242 prague20240718 ARTICLE ConferencePaper