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Physics Letters, Section B: Nuclear, Elementary Particle and High-Energy Physics


Department of Physics and Astronomy


We explore the possibility of probing flavor violations in the charged-lepton sector by means of high-luminosity lepton-photon and electron-muon collisions, by inverting initial and final states in a variety of decay channels presently used to bound such violations. In particular, we analyze the resonant lepton, γℓ→ℓ′, and neutral-meson, e−μ+→ϕ,η,π0, scattering channels, whose cross sections are critically dependent on the colliding-beams energy spread, being particularly demanding in the case of leptonic processes. For these processes, we compute upper bounds to the cross-section corresponding to present limits on the inverse decay channel rates. In order to circumvent the beam energy spread limitations we extend the analysis to processes in which a photon accompanies the resonance in the final state, compensating the off-shellness effects by radiative return. These processes might be studied at future facilities with moderate energies, in case lepton-photon and electron-muon collisions with sufficiently high luminosity will be available.



Original Citation

Gabrielli, E., Mele, B., & Onofrio, R. (2021). Bounds on charged-lepton flavor violations via resonant scattering. Physics Letters B, 822, 136656.