Double Cover of Modular $S_4$ for Flavour Model Building

P. P. Novichkov, J. T. Penedo, S. T. Petcov

We develop the formalism of the finite modular group ${\Gamma }_4^{\prime }\equiv S_4^{\prime }$, a double cover of the modular permutation group ${\Gamma }_4\simeq S_4$, for theories of flavour. The integer weig…