Strong CP problem

Strong CP problem: why does QCD not violate CP symmetry?

Quantum chromodynamics (QCD) theoretically allows for CP-symmetry violation in strong interactions, yet experiments show no such violation.

The strong CP problem arises because QCD does not have a known reason to conserve CP-symmetry, leading to a fine-tuning issue in particle physics.

Several solutions, including the Peccei–Quinn theory with axions, have been proposed to address this unsolved puzzle.

Example

No experimental evidence of CP-symmetry violation in strong interactions despite QCD's theoretical allowance.

Remember this

Understanding the strong CP problem is crucial for advancing theoretical physics and achieving a unified understanding of fundamental forces.

Text adapted from Wikipedia, licensed under CC BY-SA 4.0.

Related concepts

CP violation

CP violation discovered in 1964 neutral kaon decays

Physics beyond the Standard Model

Could the universe be hiding clues about its deepest secrets?

Mathematical formulation of the Standard Model

Ever wondered why particles behave so strangely?

CPT symmetry

CPT symmetry is conserved in all physical phenomena

Quark

Why can't you see tiny particles called quarks?

QCD (quantum chromodynamics) describes

Why can't you split up the strong force like you split up water?

Swipe through 100 ML concepts daily