Strong CP problem: Difference between revisions

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The '''strong CP problem''' is a question in [[particle physics]], which brings up the following quandary: why does [[quantum chromodynamics]] (QCD) seem to preserve [[CP violation#CP-symmetry|CP-symmetry]]?

In particle physics, '''CP''' stands for the combination of [[C-symmetry]] ([[charge conjugation symmetry]] (Csymmetry) and [[P-symmetry]] ([[Parity (physics)|parity]] symmetry (P). According to the current mathematical formulation of quantum chromodynamics, a [[CP violation|violation of CP-symmetry]] in [[strong interaction]]s could occur. However, no violation of the CP-symmetry has ever been seen in any experiment involving only the strong interaction. As there is no known reason in QCD for it to necessarily be conserved, this is a "[[Fine-tuning (physics)|fine tuning]]" problem known as the '''strong CP problem'''.

The strong CP problem is sometimes regarded as an [[List of unsolved problems in physics|unsolved problem in physics]], and has been referred to as "the most underrated puzzle in all of physics."<ref>{{cite conference |first=T. |last=Mannel |title=Theory and Phenomenology of CP Violation |book-title=Nuclear Physics B