Production of Single Heavy Charged Leptons at a Linear Collider

TL;DR

This paper investigates the production of heavy charged leptons at a linear collider, exploring one-loop processes and new physics models to assess detectability despite background challenges.

Contribution

It provides the first calculation of the e+e- -> L tau process at one-loop level and examines enhancements from two Higgs doublet and Randall-Sundrum models.

Findings

One-loop cross section for e+e- -> L tau may be detectable.

Two Higgs doublet and Randall-Sundrum models increase cross section.

Heavy charged leptons are difficult to detect at 500 GeV ILC.

Abstract

A sequential fourth generation of quarks and leptons is allowed by precision electroweak constraints if the mass splitting between the heavy quarks is between 50 and 80 GeV. Although heavy quarks can be easily detected at the LHC, it is very difficult to detect a sequential heavy charged lepton, L, due to large backgrounds. Should the L mass be above 250 GeV, it can not be pair-produced at a 500 GeV ILC. We calculate the cross section for the one-loop process e+e- -> L tau. Although the cross section is small, it may be detectable. We also consider contributions from the two Higgs doublet model and the Randall-Sundrum model, in which case the cross section can be substantially higher.