Proton-Proton Collisions (IMAGE) University of the Witwatersrand Caption Real CMS proton-proton collisions events in which 2 high energy electrons and two high energy muons are observed. Credit Taylor L; McCauley T/CERN Usage Restrictions None License Licensed content Disclaimer: AAAS and EurekAlert! are not responsible for the accuracy of news releases posted to EurekAlert! by contributing institutions or for the use of any information through the EurekAlert system.