PT Journal
AU Feruglio, F
   Gherardi, V
   Romanino, A
   Titov, A
TI Modular invariant dynamics and fermion mass hierarchies around tau = i
SO Journal of High Energy Physics
JI J. High Energy Phys.
PY 2021
BP 242
EP 26pp
VL 05
IS 5
DI 10.1007/JHEP05(2021)242
LA English
DE Beyond Standard Model; Neutrino Physics; Supersymmetric Standard Model; Compactification and String Models
AB We discuss fermion mass hierarchies within modular invariant flavour models. We analyse the neighbourhood of the self-dual point tau = i, where modular invariant theories possess a residual Z(4) invariance. In this region the breaking of Z(4) can be fully described by the spurion epsilon approximate to tau – i, that flips its sign under Z(4). Degeneracies or vanishing eigenvalues of fermion mass matrices, forced by the Z(4) symmetry at tau = i, are removed by slightly deviating from the self-dual point. Relevant mass ratios are controlled by powers of vertical bar epsilon vertical bar. We present examples where this mechanism is a key ingredient to successfully implement an hierarchical spectrum in the lepton sector, even in the presence of a non-minimal Kahler potential.
ER