Hangout with CERN: Reaching the Public with the Collaborative Tools of Social Media

On 4 July 2012, particle physics became a celebrity. Around 1,000,000,000 people (yes, 1 billion) [1] saw rebroadcasts of two technical presentations announcing the discovery of a new boson. The occasion was a joint seminar of the CMS [2] and ATLAS [3] collaborations, and the target audience were particle physicists. Yet the world ate it up like a sporting event. Roughly two days later, in a parallel session of ICHEP in Melbourne, Australia [4], a group of physicists decided to explain the significance of this discovery to the public. They used a tool called 'Hangout', part of the relatively new Google+ social media platform [5], to converse directly with the public via a webcast videoconference. The demand to join this Hangout [6] overloaded the server several times. In the end, a compromise involving Q&A; via comments was set up, and the conversation was underway. We present a new project born shortly after this experience called Hangout with CERN [7], and discuss its success in creating an effective conversational channel between the public and particle physicists. We review earlier efforts by both CMS and ATLAS contributing to this development, and then describe the current programme, involving nearly all aspects of CERN, and some topics that go well beyond that. We conclude by discussing the potential of the programme both to improve our accountability to the public and to train our community for public communication.