ICHEP 2022

The search of the X17 particle with the MEG-II detector

7 Jul 2022, 10:15

15m

Room 10 (Magenta B)

Parallel Talk Beyond the Standard Model Beyond the Standard Model

Speaker

Hicham Benmansour (University and INFN, Pisa)

Description

A resonant structure has been observed at ATOMKI in the invariant mass of electron-positron pairs, produced after excitation of nuclei such as ${}^8$Be and ${}^4$He by means of proton beams. Such a resonant structure can be interpreted as the production of an hypothetical particle (X17) whose mass is around 17 MeV.
The MEG-II experiment at the Paul Scherrer Institut whose primary physics goal is the search for the charged lepton violation process $\mu \to e\gamma$ is in the position to confirm and study this observation. MEG-II employs a source of protons able to accelerate them up to a kinetic energy of about 1 MeV. This protons are absorbed on a thin target where they excite nuclear transitions to produce photons for the Xenon calorimeter calibration of the MEG-II detector.
By using a new thinner target containing $Li$ atoms the ${}^7$Li(p,e${}^{+}$e${}^{-}$)${}^8$Be process is being studied with a magnetic spectrometer including a cylindrical drift chamber and a system of fast scintillators. This aims to reach a better invariant resolution of previous experiments and to study the production of the X17.
A first dedicated data-taking period in 2022 was conducted where the first internal pair creation events were observed. We report about the first results of the study of the X17 particle.

Presentation materials

ICHEP2022_Benmansour_0707.pdf