Search for spontaneous muon emission from lead nuclei
  We describe a possible search for muonic radioactivity from lead nuclei using the base elements ("bricks" composed by lead and nuclear emulsion sheets) of the long-baseline OPERA neutrino experiment. We present the results of a Monte Carlo simulation concerning the expected event topologies and estimates of the background events. Using few bricks, we could reach a good sensitivity level. 
L. Arrabito, D. Autiero, E. Barbuto, C. Bozza, S. Cecchini, L.   Consiglio, M. Cozzi, N. D'Ambrosio, Y. Declais, G. De Lelli...