{"paper":{"title":"Improved exclusion limit for light dark matter from $e^+e^-$ annihilation in NA64","license":"http://creativecommons.org/licenses/by/4.0/","headline":"","cross_cats":["hep-ph"],"primary_cat":"hep-ex","authors_text":"A. Celentano, A. Chumakov, A. Dermenev, A. Feshchenko, A. Gardikiotis, A. Karneyeu, A. Rubbia, A. Toropin, A. Trifonov, B. Ketzer, B. Radics, B. Vasilishin, D. Banerjee, D. Cooke, D. Kirpichnikov, D. Peshekhonov, D. Shchukin, E. Depero, G. Kekelidze, G. Vasquez, H. Sieber, I. Konorov, I. Tlisova, J. Bernhard, L. Kravchuk, L. Marsicano, L. Molina, M. Bondi, M. Hoesgen, M. Jeckel, M. Kirsanov, N. Charitonidis, N. Krasnikov, P. Crivelli, P. Ulloa, P. Volkov, R. Dusaev, R. Rojas, S. Donskov, S. Gerassimov, S. Gninenko, S. Kovalenko, S. Kuleshov, T. Enik, V. Burtsev, V. Frolov, V. Kachanov, V. Kolosov, V. Kramarenko, V. Lysan, V. Lyubovitskij, V. Matveev, V. Polyakov, V. Samoylenko, V. Tikhomirov, V. Volkov, Yu. Andreev, Yu. Mikhailov","submitted_at":"2021-08-09T17:35:42Z","abstract_excerpt":"The current most stringent constraints for the existence of sub-GeV dark matter coupling to Standard Model via a massive vector boson $A^\\prime$ were set by the NA64 experiment for the mass region $m_{A^\\prime}\\lesssim 250$ MeV, by analyzing data from the interaction of $2.84\\cdot10^{11}$ 100-GeV electrons with an active thick target and searching for missing-energy events. In this work, by including $A^\\prime$ production via secondary positron annihilation with atomic electrons, we extend these limits in the $200$-$300$ MeV region by almost an order of magnitude, touching for the first time t"},"claims":{"count":0,"items":[],"snapshot_sha256":"258153158e38e3291e3d48162225fcdb2d5a3ed65a07baac614ab91432fd4f57"},"source":{"id":"2108.04195","kind":"arxiv","version":2},"verdict":{"id":null,"model_set":{},"created_at":null,"strongest_claim":"","one_line_summary":"","pipeline_version":null,"weakest_assumption":"","pith_extraction_headline":""},"integrity":{"clean":true,"summary":{"advisory":0,"critical":0,"by_detector":{},"informational":0},"endpoint":"/pith/2108.04195/integrity.json","findings":[],"available":true,"detectors_run":[],"snapshot_sha256":"c28c3603d3b5d939e8dc4c7e95fa8dfce3d595e45f758748cecf8e644a296938"},"references":{"count":0,"sample":[],"resolved_work":0,"snapshot_sha256":"258153158e38e3291e3d48162225fcdb2d5a3ed65a07baac614ab91432fd4f57","internal_anchors":0},"formal_canon":{"evidence_count":0,"snapshot_sha256":"258153158e38e3291e3d48162225fcdb2d5a3ed65a07baac614ab91432fd4f57"},"author_claims":{"count":0,"strong_count":0,"snapshot_sha256":"258153158e38e3291e3d48162225fcdb2d5a3ed65a07baac614ab91432fd4f57"},"builder_version":"pith-number-builder-2026-05-17-v1"}