Searches for the Violation of Pauli Exclusion Principle at LNGS in   VIP(-2) experiment
  The VIP (Violation of Pauli exclusion principle) experiment and its follow-up experiment VIP-2 at the Laboratori Nazionali del Gran Sasso (LNGS) search for X-rays from Cu atomic states that are prohibited by the Pauli Exclusion Principle (PEP). The candidate events, if they exist, will originate from the transition of a $2p$ orbit electron to the ground state which is already occupied by two electrons. The present limit on the probability for PEP violation for electron is 4.7 $\times10^{-29}$ set by the VIP experiment. With upgraded detectors for high precision X-ray spectroscopy, the VIP-2 experiment will improve the sensitivity by two orders of magnitude. 
H Shi, S. Bartalucci, S. Bertolucci, C. Berucci, A. M. Bragadireanu,   M. Cargnelli, A. Clozza, C. Curceanu, L. De Paolis, S...
physics.ins-det quant-ph