Particle.news
Download on the App Store

CMS Spots Quark Wakes, Directly Showing the Primordial Plasma Behaves Like a Liquid

A Z-boson tagging technique isolated a single quark’s disturbance to enable precise study of the plasma’s properties.

Overview

  • CMS analysts mined about 13 billion heavy-ion collisions at the LHC and identified roughly 2,000 rare events with a Z boson paired with a quark.
  • The quark left a measurable wake in the quark–gluon plasma, providing direct evidence that the medium flows and responds like a liquid.
  • The observed patterns match long-standing theoretical predictions, including Krishna Rajagopal’s hybrid model of jet–medium interactions.
  • Independent experts described the measurement as the first clean, unambiguous evidence of quark-induced wakes in this extreme state of matter.
  • The peer-reviewed results, published in Physics Letters B, establish a method that can now be used to extract transport properties such as viscosity and energy loss.