Four LHC collaborations — ALICE, ATLAS, CMS and LHCb — all reported fresh signs that quark-gluon plasma formed in oxygen-oxygen and oxygen-neon collisions, extending evidence beyond the heavy-ion systems once thought necessary.
ATLAS and CMS tied that signal to parton energy loss: ATLAS saw growing jet and photon-recoil imbalances in more central collisions, while CMS found charged-particle suppression versus proton-proton collisions.
LHCb said suppression was stronger in heavier neon collisions for charm-containing particles, and ALICE used neutral-pion comparisons in oxygen-oxygen and proton-oxygen data to rule out alternative causes.
CMS and LHCb also found quarkonium suppression patterns, while ALICE reported preliminary anisotropic-flow evidence in baryons versus mesons — additional signatures consistent with quark-gluon plasma.
The result matters because quark-gluon plasma is thought to mirror matter in the first millionths of a second after the Big Bang, and these lighter-ion collisions could broaden how physicists study the early universe.