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.

Scientists on Large Hadron Collider experiments can learn about subatomic matter by peering into the collisions and asking: What exactly is doing the colliding? When the answer to that question involves rarely seen, massive particles, it gives scientists a unique way to study the Higgs boson. They can study rare, one-in-a-trillion heavy-boson collisions happening inside the LHC.