A highlight was Leprince-Ringuet's declaration in his closing talk that: "...in the future we must use particle accelerators." With the 3 GeV Cosmotron already in operation at Brookhaven National Laboratory, this declaration reflected a consensus among the participants. As a result, Rossi's group began to wind down their cloud chamber experiments. However, in 1954, Bridge, Hans Courant, Herbert DeStaebler, Jr. and Rossi reported on an unusual event in which a stopping singly charged particle decayed into three photons whose energies totaled more than the proton rest energy. This is the signature of an antiproton annihilation. The next year, a group led by Owen Chamberlain and Emilio Segrè detected antiprotons, for which they were awarded Nobel Prize in Physics in 1960.