Gluon Junction Could Carry Baryon Number, Redefining Matter's Identity
New results from the STAR detector at RHIC suggest that baryon number—the quantum identity of matter—may be carried by a gluon junction inside protons rather than solely by valence quarks. This Y-shaped gluon configuration can be stopped during collisions to form new baryons, explaining an excess of baryons perpendicular to the collision axis and challenging decades of textbook assumptions about baryon-number conservation and proton stability. The finding, reported in Science, relies on electric-charge tests that compare stopped quarks with produced baryons, indicating gluons may play a larger role in defining matter's identity than previously thought.
