Many members of the MITHIG group attended the Initial Stages 2016 conference in Lisbon, Portugal. There were two plenary talks and two parallel talks given by the MITHIG group members. Between enjoying the Portuguese seafood and Fado music, they presented exciting new results coming from the data that was gathered in the fall of 2015.
Kaya Tatar presented a new measurement of jet quenching in PbPb which uses events where a high energy jet is emitted along with a Z boson. This is the first time that a significant modification of Z+jet correlation, which is consistent with jet quenching, was observed. Austin Baty showed a measurement of the PbPb charged particle nuclear modification factor up to 400 GeV/c, significantly increasing the high pt reach of previous measurements. The nuclear modification factors extracted from Austin’s studies were found to be increasing as a function of charged particle transverse momentum, reaching a value very close to 1.
Dr. Gian Michele Innocenti presented a new measurement of the supression of D0 meson production in PbPb collisions in his plenary talk, elucidating the behavior of heavy flavor quarks in the medium. This is the widest D0 meson kinematics range ever measured in PbPb collisions. Surprisingly, the D0 nuclear modification factors wer found to be similar to the ones from charged particles. All three measurements were the first measurements performed with PbPb collision data at 5 TeV, significantly improved the statstical reach of previous measurements at lower energies, and will help elucidate the behavior of high momentum particles traversing the quark gluon plasma.
Prof. Yen-Jie Lee was also invited to give a plentary talk discussing the current status of nuclear parton distribution function measurements, their parameterizations and their importance for looking at small systems. It was shown in the talk that measurements of electroweak bosons and high pt jets, which could be performed with high accuracy, will be able to further improve our understanding of nuclear parton distribution functions. Studies of various processes will also help to verify the factorization assumptions and the universality of the nuclear parton distribution functions.