1999/05/12 by Chuan-Tsung Chan, Ernest M. Henley, Chan, Chuan-Tsung +4 · 1 citation
Physics and Astronomy · #FOS: Physical sciences #High Energy Physics - Phenomenology (hep-ph) #High-Energy Particle Collisions Research #Particle physics theoretical and experimental studies #Quantum Chromodynamics and Particle Interactions #hep-ph
paper · pdf · doi:10.48550/arxiv.hep-ph/9905317
This paper, together with hep-ph/9704427, are abridged versions of the Ph.D thesis of the first author
arxiv created 1999/05/12 · openalex publication_date 1999/05/12 · arxiv updated 2009/11/30 · openalex created_date 2025/10/10 · openalex updated_date 2026/07/28
The electric dipole moments of nucleons (NEDM, dN) are calculated using the method of QCD sum rules. Our calculations are based on the parity and time reversal violating parameter \thetabar in QCD and establish a functional dependence of the NEDM on \thetabar, without assuming a perturbative expansion of this symmetry breaking parameter. The results obtained from the QCD sum rules approach are shown to be consistent with the general symmetry constraints on CP violations in QCD, including the necessity of: (1) finite quark masses, (2) spontaneous chiral symmetry breaking, and (3) the UA(1) anomaly. Given the current experimental upper bound on the neutron electric dipole moment (nEDM), dn < 10^(-25) e-cm, we find | \thetabar | < 10^(-9). This result is compatible with previous calculations of nEDM using different techniques and excludes the possibility of solving the strong CP problem within QCD via a dynamical suppression mechanism.