Probing the contents of the early Universe with ALICE

The ALICE collaboration at CERN has measured the flow of bottomonium particles for the first time, shedding more light on the Quark-Gluon Plasma that filled the universe in its first moments.

The ALICE detector at CERN is investigating the conditions in the early universe by creating quark-gluon plasma and studying the particles which emerge. (Author’s own)

In a paper presented at the European Physical Society's conference on high-energy physics, the ‘A Large Ion Collider Experiment’ (ALICE) collaboration has documented the first-ever measurement of the flow of a heavy meson particle — bottomonium.

The measurement of particles like bottomonium — a type of upsilon particle — helps the researchers understand the Quark-Gluon Plasma (QGP) that filled the hot, dense early universe — up to 10 millionths of a second after the Big Bang.

By observing pairs of ‘heavy electrons’ — known as muons — produced by the decay of bottomonium, the team discovered bottomonium particles have small values of elliptic flow — a measure of how uniform energy and momentum is distributed across the particles when viewed from the beamline.

This is quite unexpected as all other hadrons investigated thus far have exhibited significant elliptic flow.