After barely a year of pp and a month of PbPb collisions, several exciting new results emerged from analyses led by our group. From the first 7 TeV pp collisions two summers ago novel correlations were seen in collisions producing the highest number of particles. These were never before seen in pp collisions nor were they predicted by any of the existing Monte Carlo models. This was the first manifestation of unexpected physics at the LHC which has gathered significant interest in both the media and the pp and heavy ion community.
From the start of the PbPb run we saw striking evidence in some of the first event displays of a phenomenon called jet quenching, where a colored quark or gluon passing through the QGP loses a significant fraction of its energy by interacting with the medium. While jet quenching has been observed before, the LHC was the first time you could really see it “with the naked eye”. A closer investigation of these types of collisions revealed that we may need to rethink how colored partons really interact with the QGP, since it turns out a quenched jet looks no different than a lower energy jet produced in a vacuum.
These are just a small fraction of the new and exciting discoveries and measurements being performed by the MIT group at the LHC. In less than two months a new PbPb run is coming up with an order of magnitude more collisions than last year, giving access to more precise measurements, rarer events, and potentially new discoveries.