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Axion protection from flavor

Cheung, Clifford (2010) Axion protection from flavor. Journal of High Energy Physics, 2010 (6). Art. No. 74. ISSN 1029-8479.

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The QCD axion fails to solve the strong CP problem unless all explicit PQ violating, Planck-suppressed, dimension n < 10 operators are forbidden or have exponentially small coefficients. We show that all theories with a QCD axion contain an irreducible source of explicit PQ violation which is proportional to the determinant of the Yukawa interaction matrix of colored fermions. Generically, this contribution is of low operator dimension and will drastically destabilize the axion potential, so its suppression is a necessary condition for solving the strong CP problem. We propose a mechanism whereby the PQ symmetry is kept exact up to n = 12 with the help of the very same flavor symmetries which generate the hierarchical quark masses and mixings of the SM. This “axion flavor protection” is straightforwardly realized in theories which employ radiative fermion mass generation and grand unification. A universal feature of this construction is that the heavy quark Yukawa couplings are generated at the PQ breaking scale.

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Additional Information:This article is distributed under the terms of the Creative Commons Attribution Noncommercial License which permits any noncommercial use, distribution, and reproduction in any medium, provided the original author(s) and source are credited Received: May 20, 2010. Accepted: June 6, 2010. Published: June 21, 2010. It is a pleasure to thank M. Dine and K. S. Babu for helpful discussions and comments on the draft. We especially thank J. Thaler for many helpful discussions and comments, as well as collaboration at the early stages of this work. The work of C.C. was supported by the National Science Foundation under grant PHY-0555661.
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Subject Keywords:Gauge Symmetry, Global Symmetries, Quark Masses and SM Parameters, QCD
Issue or Number:6
Record Number:CaltechAUTHORS:20190619-094159141
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Official Citation:Cheung, C. J. High Energ. Phys. (2010) 2010: 74.
Usage Policy:No commercial reproduction, distribution, display or performance rights in this work are provided.
ID Code:96537
Deposited By: George Porter
Deposited On:19 Jun 2019 22:51
Last Modified:03 Oct 2019 21:23

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