Status of charged lepton flavour violation search with MEG II experiment

The MEG II experiment searches for the Charged Lepton Flavour Violating (CLFV) decay $mu ightarrow e gamma$. This decay is foreseen by the Standard Model (SM) of Particle Physics at non observable rates through neutrino oscillation. Observing it would be a clear signal of new physics (e.g. SUSY-GUT). After publishing the current upper limit to the Branching Ratio (BR) of this decay in 2016, BR($mu^+ ightarrow e^+ gamma)<4.2 imes10^-13$, the MEG experiment started the upgrade of its detector in order to increase the sensitivity by a factor 10, starting the MEG II phase. The aim of this work is to report a description of the new detectors design and performances, to present the results obtained in the 2018 pre-engineering run with all the new MEG II detectors installed, and to report on the current status of the experiment and its future prospects.