Constraints on the masses of fourth generation quarks

TL;DR

This paper investigates how the electric dipole moment of the top quark constrains the masses of hypothetical fourth-generation quarks, providing new bounds based on one-loop contributions and existing experimental limits.

Contribution

It introduces a method to derive bounds on fourth-generation quark masses using top quark electric dipole moment measurements and theoretical mass ratios.

Findings

Limits on the down-type fourth-generation quark mass (b')

Constraints on the up-type fourth-generation quark mass (t')

Enhanced understanding of fourth-generation quark properties

Abstract

We study the one-loop contribution of the down-type quark of the standard model-like fourth generation (b') on the top quark electric dipole moment. Using the known limits on the top quark electric dipole moments, we place limits on the b' mass. Then, from the estimated ratio for the masses of the fourth generation of quarks from other studies and the achieved bound from top quark electric dipole moments on mb', we obtain a limit for the up-type quark of fourth generation (t') mass.