Sound Science Bite: February 18. What are Little Nucleons Made Of? (It's not sugar and spice.)
It was reported in the 23 Jan 2015 issue of Science that the Continuous Electron Beam Accelerator Facility (CEBAF) at Thomas Jefferson National Accelerator Facility in Newport News, Virginia, is gearing up to find out what's inside protons and neutrons, the two particles, along with electrons, that make up all matter the vast majority of us are familiar with. Protons and neutrons make up the nuclei of atoms, positively charged due to the protons. Negative electrons "swarm" about the nuclei, forming atoms. The electrons are responsible for the chemical properties of atoms, which are the basic elements from hydrogen to carbon to oxygen to ununoctium that combine into molecules that make up all "ordinary" matter.
You may have learned in school science class that protons and neutrons are both made up of three quarks: two up quarks and one down quark for the proton, two down quarks and one up quark for the neutron. These quarks are held together by the "strong" force (clever name) that is mediated by other particles called gluons. However, this picture is far too simple. The nucleons are apparently a mess with so-called "virtual" particles and antiparticles coming into and out of existence all the time as a result of Heisenberg's Uncertainty Principle in addition to the original three quarks.
Making the task of figuring out nucleons more difficult is the apparent fact that you can't isolate a single quark due to the properties of the strong force. This was satirized by the late physics Nobel Laureate Mohammad Abdus Salam, who tongue-in-cheek founded the "Quark Liberation Front" or QLF. CEBAF has been looking at nucleons for years but are now doubling the energy they use to smash electrons into various targets to see what clues come out of the debris. The higher the energy, the deeper you can probe into the nucleons. It will be interesting to see what they come up with.