Post · bonfire.cafe

@freyablekman@fediscience.org · 2 hours ago

This #CMSPaper measures for the first time the wake (yes, really, the wave created) from particles traversing the quark gluon plasma. The quark gluon plasma is a special form of matter (like gas, liquid, solid, etc. ), and it exists very shortly in the lead collisions of the LHC in heavy ion mode https://arxiv.org/abs/2602.19431

look at that wake! it doesn't agree much with the calculations btw

Observation of the jet diffusion wake using dijets in heavy ion collisions

Energetic quarks and gluons traversing a hot and dense quark-gluon plasma deposit energy and momentum into the medium before hadronizing to collimated sprays of particles, known as jets. This energy-momentum deposition is expected to produce medium responses, collectively known as jet wakes, with ``diffusion wake'' denoting a depletion of particles in the direction opposite to the propagating jet. These phenomena are studied by comparing dijet-hadron correlations measured in lead-lead (PbPb) and proton-proton (pp) collisions to assess jet-induced modifications of bulk particle production. The analysis uses PbPb and pp data recorded at a nucleon-nucleon center-of-mass energy $\sqrt{s_\mathrm{NN}}$ = 5.02 TeV with the CMS detector at the CERN LHC. By exploring how the dijet-hadron correlation distributions differ for various pseudorapidity separations of the two jets in the dijet, the presence of a jet diffusion wake is firmly established. The wake has a significance greater than 5 standard deviations for charged particles in the transverse momentum range 1 $\lt$ $p_\mathrm{T}$ $\lt$ 2 GeV. The measurements are compared with various model predictions with and without jet wake effects, providing new insights into quark-gluon plasma properties and the formation of jet-induced wakes.

1

@paulbalduf@mathstodon.xyz · 2 hours ago

@freyablekman What nice plots! This sounds interesting! How should I imagine this process? You are accelerating lead ions, but what is really colliding in the end? Is the entire nucleus squeezed together and turns into plasma? Or should I think of it as a cloud of nucleons far apart, some of which do hard collisions and the others do nothing?