Radiative Origin of Fermion Mass Hierarchy in Left-Right Symmetric Theory

TL;DR

This paper presents a left-right symmetric model explaining the fermion mass hierarchy through a radiative rank mechanism, where masses are generated sequentially from tree level to two-loop corrections without extra symmetries or scalars.

Contribution

It introduces a novel radiative rank mechanism within a left-right symmetric framework, avoiding additional scalars and relying solely on gauge interactions to generate fermion mass hierarchy.

Findings

Third-generation masses from seesaw at tree level

Second and first generations from one-loop and two-loop corrections

Model does not require extra scalars or symmetries

Abstract

Despite the remarkable success of the Standard Model, the hierarchy and patterns of fermion masses and mixings remain a profound mystery. To address this, we propose a model employing the rank mechanism, where the originally massless quarks and leptons sequentially get masses. The third-generation masses originate from the seesaw mechanism at the tree level, while those of the second and first generations emerge from one-loop and two-loop radiative corrections, respectively, with a progressive increase in the rank of the mass matrix. This approach does not require new discrete or global symmetries. Unlike other theories of this type that require the introduction of additional scalars, we employ the double seesaw mechanism within a left-right symmetric framework, which allows us to realize this scenario solely through gauge interactions.