Quantum chromodynamics

Quarks, gluons, hadrons and the collective behavior of strongly interacting matter.

A few problems to explore

7 total

Strong CP problem

The theory of the strong nuclear force permits a kind of asymmetry that experiments find to be extraordinarily small. Why is nature so close to the symmetric case?

QCD critical point

Does hot, baryon-rich nuclear matter have a critical endpoint where the character of its phase transition changes?

EMC effect

Quark distributions change when protons and neutrons are bound in nuclei. What physical mechanism causes those changes?

Proton spin

A proton’s total spin is known. How is it shared among quark spin, gluon spin and their orbital motion?

Hadronic vacuum polarization

Different methods still disagree on parts of the hadronic contribution to the muon’s magnetic moment. Which data or corrections explain the differences?

Browse all 7 problems