Description
The MEG II experiment at the Paul Scherrer Institute primarily aims to search for Physics beyond the Standard Model through the investigation of charged lepton flavor violation in the $\mu^+$ $\rightarrow$ $e^+ \gamma$ process.
However, it is also capable of searching for new particles.
We present a search for the X17, a hypothetical particle proposed to explain a resonant structure observed at ATOMKI in the opening angle of the electron-positron pairs, produced following the excitation of nuclei such as $^8$Be, $^4$He and $^{12}$C by proton beams.
MEG~II has a CW accelerator that delivers protons with a kinetic energy up to 1.1 MeV. These protons impinge on a Li-based target, inducing nuclear transitions that produce photons used for the calibration of the Xenon calorimeter in the MEG~II detector.
By using dedicated targets (with thicknesses up to several $\rm{\mu m}$) 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 achieve a higher resolution than previous experiments and to study X17 production with greater acceptance, thereby providing deeper insight into the nature of this observation.
The results of the first four-weeks data-taking run conducted in 2023 and future prospects will be presented.
