Nuclear physics input to charged lepton flavor violation (ℓ → ℓ′ conversion in nuclei)

Lepton flavor violation (LFV) has only been observed so far through neutrino oscillations, implying tiny but non-vanishing neutrino masses. The discovery of this violation in the charged lepton sector (cLFV), so far elusive, would have tremendous implications for the mechanism generating neutrino masses and possibly for understanding the universe matter-antimatter asymmetry, at energy scales prone to grand unification. In the near future, the best bounds on muon-to-electron transitions will be obtained from their conversions in nuclei, highlighting the importance of the overlap integrals between the lepton wave functions under the nucleus Coulomb potential and the nucleon densities. The electron/muon-to-tau conversion searches (which will start soon) will benefit from improved nuclear parton distribution functions (NPDFs).