New-physics signatures via CP violation in η (0) → π 0µ +µ − and η 0 → ηµ+µ − decays

In this work we investigate the prospect of observing new-physics signatures via CP violation in eta((')) -> pi(0) mu(+) mu(-) and eta'-> eta mu(+) mu(-) decays at the REDTOP experiment. We make use of the SMEFT to parametrise the new-physics CP-violating effects and find that the projected REDTOP statistics are not competitive with respect to nEDM experiments. This reasserts the eta -> mu(+) mu(-) process as the most promising channel to find CP-violation at this experimental facility.