Lepton flavor violation via four-Fermi contact interactions at the International Linear Collider

TL;DR

This paper investigates lepton flavor violation via four-Fermi contact interactions at the ILC, demonstrating improved sensitivity and tighter bounds on LFV couplings compared to previous experiments, especially with polarized beams.

Contribution

It presents a detailed analysis of LFV processes at the ILC, showing enhanced sensitivity and tighter bounds on LFV couplings using polarized beams and different collision energies.

Findings

ILC can detect smaller LFV couplings than B-factories.

Polarized beams significantly improve bounds on LFV couplings.

Higher collision energy further tightens the constraints.

Abstract

Lepton flavor violating (LFV) process $e^+ e^- \to e^+ \tau^-$ induced by the four-Fermi contact interactions at the International Linear Collider (ILC) is studied. Taking account of the event selection conditions, it is shown that the ILC is sensitive to smaller LFV couplings as compared to the measurement of $\tau\to 3e$ process at the B-factory experiment. The upper bounds on some of the LFV couplings are improved by several factors using polarized $e^-/e^+$ beams at $\sqrt{s}=250~\mathrm{GeV}$ and by an order of magnitude at $\sqrt{s}=1~\mathrm{TeV}$.