Brookhaven physicists find evidence a gluon 'junction', not the three quarks alone, carries a proton's baryon number
A new STAR detector study at Brookhaven National Laboratory's RHIC collider, published in the journal Science, finds evidence that a Y-shaped junction of gluons - not a proton's three individual quarks - may be the primary carrier of baryon number, the property that keeps protons stable. Per Brookhaven National Laboratory and Rice University.
Physicists on the STAR collaboration at Brookhaven National Laboratory's Relativistic Heavy Ion Collider report evidence that baryon number, the quantum property responsible for a proton's stability, may be carried primarily by a Y-shaped 'junction' of gluons connecting its three quarks rather than by the quarks themselves, the traditional textbook view under which each of the three valence quarks was assumed to carry one third of the baryon number. The team compared baryon counts to electric-charge measurements from RHIC nuclear collisions and found roughly twice as many baryons emerging perpendicular to the beamline as the quark-only model predicts, evidence they say supports the decades-old gluon junction idea first proposed in the 1970s and refined by theorist Dmitri Kharzeev in 1996. Baryon number conservation is also why physicists believe a proton's lifetime exceeds the age of the universe. The study, 'Tracking the baryon number with nuclear collisions,' was published in Science. Sources: Brookhaven National Laboratory, Rice University, ScienceDaily.