5 Discoveries Made by the Large Hadron Collider (So Far)

Coordinated Motion
The soup du jour at CERN is a hearty quark-gluon plasma. Wavebreakmedia Ltd/Wavebreak Media/Thinkstock

When scientists calibrating LHC instruments skipped the usual proton-proton collisions and opted instead to ram protons into lead nuclei, they noted a surprising phenomenon: The random paths that the resulting subatomic shrapnel usually took had been replaced by an apparent coordination.

One theory advanced to explain the phenomenon says that the impact created an exotic state of matter called quark-gluon plasma (QGP), which flowed like liquid and produced coordinated particles as it cooled. Both Brookhaven National Laboratories and the LHC have previously created QGP -- the densest form of matter outside of a black hole -- by colliding heavy ions like lead and gold. If QGP from a proton-lead collision proves possible, it could significantly affect ideas how scientist view conditions immediately following the Big Bang, when QGP had its brief heyday. There's just one problem: The collision should not have had enough energy to churn out the hypothesized quark soup [sources: CERN; Grant; Roland and Nguyen; Than].

Although most physicists favor this idea despite its problems, some have argued for a second explanation involving a theoretical field created by gluons, the particles that mediate strong force and paste quarks and antiquarks into protons and neutrons. The hypothesis says that gluons zipping along at near light speed form fields that cause them to interact. If correct, this model could provide valuable insights into proton structure and interaction [sources: Grant].