Why PQ?

Abstract

I discuss how the solution of the $U(1{)}_A$ problem of QCD through the existence of the $\theta$-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: $U(1{)}_{PQ}$

Invited talk given at the Axion 2010 Conference, January 15-17, 2010, Univ. of Florida, Gainsville, FL

References in corpus (2)

• The $\eta$ and ${\eta }^{\prime }$ mesons from Lattice QCD
• MILC results for light pseudoscalars

Cited by in corpus (7)

• Midi-review: Status of weak scale supersymmetry after LHC Run 2 and ton-scale noble liquid WIMP searches
• Some necessary conditions for allowing the PQ scale as high as M_{GUT} in SUSY models with an axino or neutralino LSP
• Topology in the SU(Nf) chiral symmetry restored phase of unquenched QCD and axion cosmology
• Massive Schwinger model at finite $\theta$
• (Mainly) axion dark matter
• Phenomenological implications of $S$-duality symmetry
• An Analytic Treatment of Underdamped Axionic Blue Isocurvature Perturbations