# Discriminating leptonic Yukawa interactions with doubly charged scalar at the ILC

## TL;DR

This paper proposes a method to distinguish two types of leptonic Yukawa interactions involving doubly charged scalars at the ILC by analyzing scattering asymmetries and combining collider and lepton flavor violation constraints.

## Contribution

It introduces a novel approach to differentiate leptonic Yukawa interactions using angular asymmetries and combined experimental constraints at future colliders.

## Key findings

- Sensitivity estimates for Yukawa interaction discrimination at the ILC.
- Upper bounds on Yukawa couplings from collider and lepton flavor violation data.
- Feasibility of distinguishing scalar interaction types with polarized beams.

## Abstract

We explore discrimination of two types of leptonic Yukawa interactions associated with Higgs triplet, $\bar L^c_L \Delta L_L$, and with $SU(2)$ singlet doubly charged scalar, $\bar e_R^c k^{++} e_R$. These interactions can be distinguished by measuring the effects of doubly charged scalar boson exchange in the $e^+ e^- \to \ell^+ ell^-$ processes at polarized electron-positron colliders. We study a forward-backward asymmetry of scattering angular distribution to estimate the sensitivity for these effects at the ILC. In addition, we investigate prospects of upper bounds on the Yukawa couplings by combining the constraints of lepton flavor violation processes and the $e^+ e^- \to \ell^+ \ell^-$ processes at the LEP and the ILC.