The “Glue” Inside Protons May Hold the Secret to Matter’s Identity

Key Points:

• New findings from the STAR detector at RHIC suggest that baryon number, a fundamental quantum property, may be carried by a Y-shaped gluon junction inside protons rather than solely by their three valence quarks, challenging a decades-old assumption.
• The research shows an excess of baryons produced perpendicular to collision beams that cannot be explained by quark behavior alone, indicating that gluon junctions may be easier to stop and convert into new baryons during high-energy nuclear collisions.
• This discovery has broad implications for understanding baryon number conservation, which is tied to the stability of protons, the matter-antimatter imbalance in the universe, and the fundamental structure of matter as described by quantum chromodynamics.
• By comparing baryon number production with electric charge redistribution in collisions, the STAR team provided strong evidence supporting the role of gluon junctions, reshaping the traditional textbook view that baryon number is divided among three quarks.
• The study, published in Science and supported by DOE and NSF, deepens knowledge of proton structure and the strong force, potentially impacting nuclear physics and cosmology by explaining how baryon number is preserved in the universe.