Citation:
Del Amo Sanchez P, Lees J P, Poireau V, Prencipe E, Tisserand V, Garra Tico J, Grauges E, Martinelli M, Milanes D A, Palano A, et al. Search for Production of Invisible Final States in Single-Photon Decays of \ensuremath\Upsilon(1S). \prl. 2011;107 (2) :021804.