Protons’ antimatter is even more lopsided than we thought
Protons are built from three quarks — two “up” quarks and one “down” quark. But they also contain a roiling sea of transient quarks and antiquarks that fluctuate into existence before swiftly annihilating one another. At the Fermilab-hosted SeaQuest experiment, researchers report that that lopsidedness persists in a realm of previously unexplored quark momenta.