For the month of November the LHC switched to colliding 2.76 TeV lead nuclei. The heavy ion group was heavily involved in the data taking which resulted in a very rich, high statistics dataset. This year’s recorded luminosity is 20 times higher than last year’s data giving us access to more precise measurements of known phenomena as well as new measurements and probes available for the first time ever in heavy ion physics.
In a little over two months after the end of data taking we published an updated dijet imbalance paper taking advantage of the full 2011 high statistics dataset. In addition to analyzing new 2011 data we finalized the measurements first shown at Quark Matter and published those in three new papers. The first paper of 2012 is the measurement of isolated photon production in pp and PbPb collisions at 2.76 TeV , where the transverse energy distributions are found to be in good agreement with next-to-leading-order perturbative QCD predictions and the ratio of PbPb to pp isolated photon ET-differential yields is consistent with unity for all PbPb centralities.
Next came the study of dihardon correlations and azimuthal anisotropy harmonics where we show the evolution of short (jet) and long range range correlations with increasing centrality and transverse momentum, as well as the single particle azimuthal harmonics up to fifth order from a Fourier analysis.
The most recent completed paper is the measurement of high transverse momentum charged particle suppression. We find the charged particle yield is suppresed by a factor of 5 compared to pp collisions in the transverse momentum range of 5-10 GeV/c and rises to a factor of 2 in the 40-100 GeV/c range.