Protons, once thought to be fundamental particles, have been known since 1968 to instead be composed of quarks. Some quarks are actually heavier than protons, but this wasn’t considered a problem because protons were thought to be made up purely of light quarks – two up and one down quark to be precise. However, new research shows protons also contain charm quarks, which are indeed heavier than protons, like a pot holding a bigger pot inside it.
“That goes against all common sense,” said Dr Juan Rojo of Vrije Universiteit Amsterdam in a statement. “It’s like buying a one-kilogram pack of salt, which then comes out two kilograms of sand.”
However, anyone highly attached to common sense dropped out of quantum mechanics courses in the first six weeks, so Rojo and co-authors were undeterred. In Nature they have revealed that less than one percent of the proton’s mass comes from quarks heavier than the proton.
