New paper “Excluding MeV-scale QCD axions by K_L → π0 π0 a at KTeV” [arXiv:2602.15117]
Published:
Posted a new paper with colleagues at Osaka University: Takaya Iwai, Prof. Ryosuke Sato, and Takumu Yamanaka.
[arXiv:2602.15117] To be published in JHEP
A QCD axion with a mass near 10 MeV that couples to the up quark, down quark, and electron was proposed as a viable possibility. In this paper, we reexamine it with kaon decays.
- Analyze the K_L → π0 π0 e+ e- measurement of the KTeV experiment in detail.
- Reinterpret the K+ decay measurements at E949 and NA62 for the diphoton and effectively invisible decay modes of the axion.
- Find that the viable window is excluded, mainly by the KTeV bound, even after accounting for the uncertainties of the chiral Lagrangian.