Operation of the new CGEM Inner Tracker for the Upgrade of the BESIII Experiment

Abstract

A ten years extension of the data taking of BESIII experiment, recently approved, motivated an upgrade program both for the leptonic collider BEPCII and for some of the sub-detectors of the spectrometer. In particular, the current inner drift chamber is suffering from aging and the proposal is to replace it with a detector based on cylindrical GEM technology. The CGEM detector is made of three coaxial layers of triple GEM. The tracker is expected to restore the efficiency, to improve the z determination and the secondary vertex position reconstruction with respect to the current inner tracker, with a resolution of 130 µm in xy plane and better than 350 µm along the beam direction. A cosmic telescope instrumented with two out of three layers is in operation in Beijing since January 2020, remotely controlled by Italian groups due to the pandemic situation. In this presentation, the general status of the project will be presented with a particular focus on the preliminary results from the cosmic data taking and future plans.