Progress in the development of Neganov-Trofimov-Luke assisted light detectors for the CUPID experiment.

CUPID (Cuore Upgrade with Particle IDentification), the successor of CUORE, is a next-generation experiment aiming to investigate the Majorana nature of the neutrino. It will search for neutrinoless double beta decays (0ν2β) of ¹⁰⁰Mo embedded inside Li₂MoO₄ scintillating crystals operated at mK temperatures and coupled to thin Ge bolometric light detectors. This configuration permits simultaneous detection of the heat and the light produced by an energy deposition in the crystal, which provides an efficient way to discriminate the alpha background. This presentation will focus on the recent developments of enhanced light detectors using the so-called Neganov-Trofimov-Luke (NTL) effect to amplify the light signal. They are the key to rejecting the contribution to the background from the pile-up events, which is expected to dominate the CUPID background due to the slow bolometric signal and the relatively fast ¹⁰⁰Mo 2ν2β. The NTL light detector technology has recently been integrated into the CUPID baseline design, and numerous developments are ongoing within the collaboration to optimize their performance and demonstrate their suitability for the project. The most recent progress will be presented.