Quark flavor phenomenology of the QCD axion

Jorge Martin Camalich, Maxim Pospelov, Pham Ngoc Hoa Vuong, Robert Ziegler, Jure Zupan

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17 Scopus citations


Axion models with generation-dependent Peccei-Quinn charges can lead to flavor-changing neutral currents, thus motivating QCD axion searches at precision flavor experiments. We rigorously derive limits on the most general effective flavor-violating couplings from current measurements and assess their discovery potential. For two-body decays, we use available experimental data to derive limits on q→q′a decay rates for all flavor transitions. Axion contributions to neutral-meson mixing are calculated in a systematic way using chiral perturbation theory and operator product expansion. We also discuss in detail baryonic decays and three-body meson decays, which can lead to the best search strategies for some of the couplings. For instance, a strong limit on the Λ→na transition can be derived from the supernova SN 1987A. In the near future, dedicated searches for q→q′a decays at ongoing experiments could potentially test Peccei-Quinn breaking scales up to 1012 GeV at NA62 or KOTO and up to 109 GeV at Belle II or BES III.

Original languageEnglish (US)
Article number015023
JournalPhysical Review D
Issue number1
StatePublished - Jul 1 2020

Bibliographical note

Funding Information:
We thank Daniel Craik, Marko Gersabeck, Pablo Goldenzweig, Aida El-Khadra, Martin Heeck, Phil Ilten, Alex Kagan, Hajime Muramatsu, Uli Nierste, Steven Robertson, Giuseppe Ruggiero, Luca Silvestrini, Abner Soffer, Emmanuel Stamou, Sheldon Stone, Olcyr Sumensari, Shiro Suzuki, and Javier Virto for useful discussions. J. M. C. acknowledges support from the Spanish MINECO through the “Ramón y Cajal” Program No. RYC-2016-20672 and Grant No. PGC2018-102016-A-I00. J. Z. acknowledges support in part by the DOE Grant No. DE-SC0011784. P. N. H. V. acknowledges support from the Non-Member State CERN Summer Student Programme.

Publisher Copyright:
© 2020 authors. Published by the American Physical Society.


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