Abstract
We show that models in which the strong CP problem is solved by introducing an axion field with a mass enhanced by non-QCD UV dynamics at a scale ΛSI exhibit enhanced sensitivity to external sources of CP violation. In the presence of higher-dimensional CP-odd sources at a scale ΛCP, the same mechanisms that enhance the axion mass also modify the axion potential, shifting the potential minimum by a factor Lambda;SI2/ΛCP2. This phenomenon of CP-violation enhancement, which puts stringent constraints on the scale of new physics, is explicitly demonstrated within a broad class of "small instanton"models with CP-odd sources arising from the dimension-six Weinberg gluonic and four-fermion operators. We find that for heavy axion masses 100 MeV, arising from new dynamics at ΛSI 1010 GeV, CP violation generated up to the Planck scale can be probed by future electric dipole moment experiments.
| Original language | English (US) |
|---|---|
| Article number | 015030 |
| Journal | Physical Review D |
| Volume | 106 |
| Issue number | 1 |
| DOIs | |
| State | Published - Jul 1 2022 |
Bibliographical note
Funding Information:T. G. thanks Raymond Co and Keisuke Harigaya for useful discussions. This work is supported in part by the Department of Energy under Grant No. DE-SC0011842 at the University of Minnesota. T. G. is also supported by the Simons Foundation.
Publisher Copyright:
© 2022 authors. Published by the American Physical Society.