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FIELD Phys:Particle Physics
DATE January 19 (Tue), 2021
TIME 10:00-12:00
PLACE Online
SPEAKER Alves , Daniele S. M.
HOST Kang, Dong Woo
INSTITUTE Los Alamos National Laboratory
TITLE Signals of the QCD axion with mass of 17 MeV
ABSTRACT The PQ mechanism was conceived to address a problem intrinsic to the nonperturbative dynamics of QCD. Yet, presently, the prevalent view is that PQ symmetry breaking should take place at scales separated from ΛQCD by at least 10 orders of magnitude. Such wide separation of scales makes the PQ cancellation of the strong CP phase vulnerable to spoiling effects. In this talk, I will discuss an alternative implementation of the PQ mechanism at low scales O(1 GeV), which would imply a QCD axion with mass O(10 MeV), and the conditions for its experimental viability. Remarkably, these conditions are precisely the ones required to explain recently observed anomalies in nuclear de-excitations, to wit: the e+e- emission spectra of isoscalar magnetic transitions of 8Be and 4He nuclei showed a “bump-like” feature peaked at an e+e- invariant mass of 17 MeV, which could be an indication of on-shell emission of a 17 MeV QCD axion. I will also present estimations of various axionic signatures in rare light meson decays, which could be probed in the near future in Eta and Kaon factories.
FILE 861551611022913729_1.pdf
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