IFIC seminars: "Casting light on the X17 particle with the NA64 experiment at CERN"

por Dr. Luca Marsicano (INFN Genova)

martes 10 feb. 2026 12:00 → 13:30 Europe/Madrid

1001-Primera-1-1-1 - Paterna. Seminario (Universe)

The anomaly recently observed by the ATOMKI collaboration in the angular correlations of electron–positron pairs emitted in nuclear transitions of 8Be, 4He and 12C has attracted significant attention in the particle physics community. This effect can be interpreted as the emission of a bosonic particle with a mass of 17 MeV, commonly referred to as the X17 particle. If confirmed, such a particle would constitute clear evidence of physics beyond the Standard Model. After an introduction to the ATOMKI anomaly, including a summary of the experimental observations and theoretical interpretations, this seminar will cover the current status of the X17 searches at particle accelerators, highlighting results from several experiments, including MEG, PADME and NA64, emphasizing the complementary experimental strategies employed in this search. I will then focus on the NA64 experiment, which uses high-intensity electron and muon beams to search for feebly interacting particles at CERN SPS. Existing NA64 results in the X17 search will be discussed, followed by prospects for possible future measurements, aimed at providing a decisive test of the X17 explanation of the ATOMKI anomaly.