New results from the STAR detector at the Relativistic Heavy Ion Collider (RHIC) suggest that gluons, the gluelike particles that hold quarks together inside protons, play a central role in the conservation of baryon number, an essential part of a particle’s quantum identity. The findings, published in the journal Science, suggest that baryon number is carried by a Y-shaped “junction” of gluons connecting the proton’s three main quarks, challenging a long-held view that baryon number is solely carried by those three quarks…

“Since the big bang, the number of protons and neutrons all together never changes as a function of time,” Lewis said. “The reasons for this conservation are not well understood. It’s one of the mysteries of the universe, related to why we have more matter than antimatter.” …

According to the STAR team’s study, when the protons that make up nuclei collide at RHIC, the quark-connecting “gluon junction” or “baryon junction” can be stopped much more easily than the three quarks; all its energy is transformed into new baryons that spray out in perpendicular directions while the quarks it usually connects continue to fly down the beampipe…