A threshold-improved narrow-width approximation for BSM physics

TL;DR

This paper introduces a refined narrow-width approximation method that improves the accuracy of predictions for resonant particle decays, especially relevant for BSM physics searches.

Contribution

It proposes a modified narrow-width approximation that achieves O(Gamma/M) accuracy, enhancing predictions for resonant processes in BSM scenarios.

Findings

Demonstrates the method's application to MSSM processes.

Shows improved prediction accuracy for resonant decays.

Highlights significance for BSM particle searches.

Abstract

A modified narrow-width approximation that allows for O(Gamma/M)-accurate predictions for resonant particle decay with similar intermediate masses is proposed and applied to MSSM processes to demonstrate its importance for searches for particle physics beyond the Standard Model.