Physicists report strongest evidence yet for the gluon-only glueball
A BESIII collaboration study analyzing about ten billion J/psi decays presents strong evidence that the X(2370) meson is predominantly a glueball—a bound state of gluons predicted by quantum chromodynamics. A 2024 spin-parity measurement (0−+) aligned with glueball predictions strengthens the case, though no single smoking-gun proof exists. If confirmed, this would demonstrate gluons interacting with themselves and shed light on the origin of mass in protons.