For understanding the hierarchies of fermion masses and mixing,we extend the Standard Model(SM)gauge group with U(1)_(X) and Z_(2) symmetry.The field content of the SM is augmented by three heavy right-handed neutrino...For understanding the hierarchies of fermion masses and mixing,we extend the Standard Model(SM)gauge group with U(1)_(X) and Z_(2) symmetry.The field content of the SM is augmented by three heavy right-handed neutrinos,two new scalar singlets,and a scalar doublet.U(1)_(X) charges of different fields are determined after satisfying anomaly cancellation conditions.In this scenario,the fermion masses are generated through higher-dimensional effective operators with O(1)Yukawa couplings.The small neutrino masses are obtained through type-1 seesaw mechanism using the heavy right-handed neutrino fields,whose masses are generated by the new scalar fields.We discuss the flavour-changing neutral current processes that arise due to the sequential nature of U(1)_(X) symmetry.We have written effective higher-dimensional operators in terms of renormalizable dimension-four operators by introducing vector-like fermions.展开更多
基金ARS thanks the Ministry of Minority Affairs,Government of India,for financial support through Maulana Azad National Fellowship under Grant No.F.82-27/2019(SA-Ⅲ).
文摘For understanding the hierarchies of fermion masses and mixing,we extend the Standard Model(SM)gauge group with U(1)_(X) and Z_(2) symmetry.The field content of the SM is augmented by three heavy right-handed neutrinos,two new scalar singlets,and a scalar doublet.U(1)_(X) charges of different fields are determined after satisfying anomaly cancellation conditions.In this scenario,the fermion masses are generated through higher-dimensional effective operators with O(1)Yukawa couplings.The small neutrino masses are obtained through type-1 seesaw mechanism using the heavy right-handed neutrino fields,whose masses are generated by the new scalar fields.We discuss the flavour-changing neutral current processes that arise due to the sequential nature of U(1)_(X) symmetry.We have written effective higher-dimensional operators in terms of renormalizable dimension-four operators by introducing vector-like fermions.
