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arXiv · 1005.0643

Why PQ?

R. D. Peccei
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Abstract

I discuss how the solution of the $U(1)_A$ problem of QCD through the existence of the $θ$-vacuum gave rise to the strong CP problem. After examining various suggested solutions to this problem, I conclude that the only viable solution still is the one that involves the existence of a spontaneously broken chiral symmetry: $U(1)_{PQ}$

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R. D. Peccei. 2010-05-04. Why PQ?. https://doi.org/10.1063/1.3489562

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