New-physics signatures via CP violation in η (′) → π 0 μ + μ − and η′ → ημ + μ − decays
Rafel Escribano (Institut de Física d’Altes Energies (IFAE), The Barcelona Institute of Science and Technology, Campus UAB, Bellaterra (Barcelona), 08193, Spain, Grup de Física Teòrica, Departament de Física, Universitat Autònoma de Barcelona, Bellaterra (Barcelona), 08193, Spain); Emilio Royo (Institut de Física d’Altes Energies (IFAE), The Barcelona Institute of Science and Technology, Campus UAB, Bellaterra (Barcelona), 08193, Spain, Grup de Física Teòrica, Departament de Física, Universitat Autònoma de Barcelona, Bellaterra (Barcelona), 08193, Spain); Pablo Sanchez-Puertas (Institut de Física d’Altes Energies (IFAE), The Barcelona Institute of Science and Technology, Campus UAB, Bellaterra (Barcelona), 08193, Spain)
In this work we investigate the prospect of observing new-physics signatures via CP violation in η (′) → π 0 μ + μ − and η′ → ημ + μ − 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 η → μ + μ − process as the most promising channel to find CP-violation at this experimental facility.
