The XXVII Quark Matter conference on ultrarelativistic heavy ion collisions was held recently in Venice, Italy from May 12 to May 19. The MIT Heavy Ion Group sent a 14-member delegation to the conference, and set a record with 8 parallel talks and 2 posters being accepted. Early on May 15, Austin Baty kicked off the proceedings with his talk on “Charged particle nuclear modification factors in pPb, PbPb and XeXe collisions with the CMS experiment“, showing for the first time, measurements of charged-hadron suppression in xenon-xenon collisions at the LHC.
He was followed by Jing Wang, who gave her talk on “D-meson production in jets in pp and PbPb collisions with the CMS detector“, an effort to better understand the production of heavy-flavor mesons. Kaya Tatar presented measurements of jet substructure in photon-tagged events, making use of the photon to trace the energy of jets back to the original hard scattering: “Jet fragmentation and shapes for inclusive, b-tagged, and photon-tagged jets in pp and PbPb collisions with the CMS detector“. To round up, Christopher McGinn presented various improvements to jet reconstruction techniques in the high-background environment found in heavy ion collisions: “Measurement of Jets in PbPb Collisions at 5.02 TeV with CMS“.
Professor Yen-Jie Lee gave a very interesting presentation on “Long-range angular correlations of charged particles in high multiplicity e+e- collisions using archived data from the ALEPH detector at LEP“, framed in the context of trying to understand the origin of flow in small systems. This measurement was also the subject of a poster by Anthony Badea, an undergraduate student in our group who made leading contributions to this analysis.
In the open heavy flavor sessions, Zhaozhong Shi presented results on measurements of D-mesons: “Measurements of D meson nuclear modification factors and of direct and elliptic flow of D0 mesons in pPb and PbPb collisions at 5.02 with CMS“. Ta-Wei Wang subsequently presented the first measurement of Bs mesons in heavy ion collisions “Measurements of strange and non strange beauty production in PbPb collisions at 5.02 TeV with the CMS detector“, helping to further the understanding of strangeness enhancement in heavy ion collisions. Last but not least, the measurements of charged-hadron multiplicities in xenon-xenon collisions was presentedby Ran Bi: “Multiplicity and transverse energy measurements from pp, pPb, PbPb and XeXe collisions with the CMS experiment“
The past year has been a fruitful one for the MIT heavy ion group, and also for the heavy ion community in general. Looking to the future, there will be a last round of heavy ion collisions before the LHC takes a break and shuts down for 3 years. We expect to collect 3-4 times the total amount of data we currently have, and we hope that the following years will be equally productive as the past few.