With preparations for the upcoming LHC heavy ion Run 2 in full swing, the heavy ion community took a brief break to review exciting new results from Run 1 data at Quark Matter XXV. This year’s conference was held on Rokk? Island in Kobe, Japan, from September 27 to October 3.
Members of the MIT Heavy Ion Group were in attendance, with everyone contributing to the proceedings. Gunther Roland gave a lecture on hard probes of the Quark Gluon Plasma (QGP) to many bright-eyed graduate students and postdocs at the preparatory student day. The next day, Yen-Jie Lee successfully managed to summarize all the new CMS results in only five minutes during his ‘teaser talk.’ Yen-Jie also presented an impressive poster detailing CMS’s ability to reconstruct D mesons in PbPb events.
Austin Baty presented an important measurement of jet fragmentation functions in pPb events, exploring the relationship between jets and the charged particles they produce. The result indicates that the fragmentation function modification previously observed by the MIT group in PbPb events (see the June 4, 2014 entry on this page) is indeed a signature of the QGP and not due cold nuclear effects. Finally, Chris McGinn showed a large update of the ‘missing pt’ measurement previously shown at Quark Matter 2014. In particular he emphasized nontrivial dijet structures present in both PbPb and (perhaps surprisingly) pp collisions caused by the existence of three or more jets in the event. The result is now submitted to JHEP and is available at arXiv:1509.09029.
CMS also presented multiple exciting new results on collective behavior in small systems – a topic which was heavily discussed and debated at the conference. The group is now working hard to ensure Run 2 goes smoothly this November.
