X17 search project with EAR2 neutron beam

We present the state of the art of the n_TOF Collaboration Working Group activity dedicated to study how to solve the puzzle about the existence of the so called new particle X17, spotted for the first time few years ago by a team at ATOMKI in Hungary and since then never confirmed by other independent experimental collaborations but also never refuted. An ad hoc detection setup is under realization for this goal, in order to reach an angular resolution of the two emerging trajectories from the X17 decay and an energy resolution for the invariant mass reconstruction enough to cast light in a definitive way about this puzzle. To design the present detection setup we work in close contact with the Pisa Nuclear Theory team, that has deeply studied the implication of X17 existence and extracted by the ATOMKI results its eventual nature, kinematics and general properties.

Automated summary

We present the latest progress of the n_TOF Collaboration Working Group in solving the puzzle of the existence of the new particle X17, first observed by the ATOMKI team in Hungary a few years ago but not confirmed or refuted by other independent experimental collaborations. We are designing a detection setup to achieve sufficient angular and energy resolution for measuring the decay paths and properties of X17, in collaboration with the Pisa Nuclear Theory team who has extensively studied the implications and characteristics of X17 based on the ATOMKI results.