Spin identification of the mono-Z$^{\prime}$ resonance in muon-pair production at the ILC with simulated electron-positron collisions at $\sqrt{s}$ = 500 GeV

TL;DR

This study analyzes the angular distribution of muon pairs at the ILC to identify potential signals of a new spin-1 Z' boson, setting limits on its mass in the absence of new physics discoveries.

Contribution

It introduces a method to distinguish Z' signals from Standard Model background using angular distributions in simulated electron-positron collisions.

Findings

No new physics observed; limits set on Z' and dark matter particle masses.

Angular distribution analysis can effectively differentiate between Standard Model and beyond Standard Model scenarios.

Abstract

In this analysis, we examine the angular distribution of low-mass dimuon pairs produced in simulated electron-positron collisions at the proposed International Linear Collider (ILC), which operates at a center-of-mass energy of 500 GeV and has an integrated luminosity of 4 ab\(^{-1}\). Our focus is on the cos\(\theta_{\text{CS}}\) variable, which is defined in the Collins-Soper frame. In the Standard Model, the production of low-mass dimuon pairs is primarily driven by the Drell-Yan process, which exhibits a notable forward-backward asymmetry. However, many scenarios beyond the Standard Model predict different shapes for the cos\(\theta_{\text{CS}}\) distribution. This angular distribution can be valuable for distinguishing between these models, especially in the event of observing excesses beyond the Standard Model expectations. We utilized the mono-Z\(^{\prime}\) model to interpret the simulated data. In the absence of any discoveries of new physics, we establish upper limits at the 95\% confidence level on the masses of various particles in the model, which includes the spin-1 \(Z^{\prime}\) boson and fermionic dark matter.