Precision tools and models to narrow in on the 750 GeV diphoton resonance

TL;DR

This paper develops precise computational tools and models to analyze the 750 GeV diphoton resonance, addressing previous oversights and enabling detailed numerical studies of potential explanations within various theoretical frameworks.

Contribution

It introduces a collection of model files for SARAH, extends spectrum generators with higher order corrections, and demonstrates their application through a new supersymmetric model for the diphoton excess.

Findings

Created 40 model files for SARAH to study the resonance.

Extended spectrum generators to include higher order decay corrections.

Demonstrated the setup with a supersymmetric model fitting the excess.

Abstract

The hints for a new resonance at 750 GeV from ATLAS and CMS have triggered a significant amount of attention. Since the simplest extensions of the standard model cannot accommodate the observation, many alternatives have been considered to explain the excess. Here we focus on several proposed renormalisable weakly-coupled models and revisit results given in the literature. We point out that physically important subtleties are often missed or neglected. To facilitate the study of the excess we have created a collection of 40 model files, selected from recent literature, for the Mathematica package SARAH. With SARAH one can generate files to perform numerical studies using the tailor-made spectrum generators FlexibleSUSY and SPheno. These have been extended to automatically include crucial higher order corrections to the diphoton and digluon decay rates for both CP-even and CP-odd scalars. Additionally, we have extended the UFO and CalcHep interfaces of SARAH, to pass the precise information about the effective vertices from the spectrum generator to a Monte-Carlo tool. Finally, as an example to demonstrate the power of the entire setup, we present a new supersymmetric model that accommodates the diphoton excess, explicitly demonstrating how a large width can be obtained. We explicitly show several steps in detail to elucidate the use of these public tools in the precision study of this model.