New Physics at 1 TeV?

TL;DR

This paper explores potential new physics explanations for the 750 GeV diphoton excess at the LHC, focusing on heavy particle decays via gluon or photon fusion mechanisms within the Standard Model framework.

Contribution

It analyzes two scenarios involving heavy isosinglet quarks and leptons to account for the diphoton excess, highlighting the requirements for heavy leptons in the photon fusion case.

Findings

Gluon fusion via heavy quark loops can explain the excess within the Standard Model.

Photon fusion requires many heavy leptons or large electric charges to match observed data.

Both scenarios provide viable explanations for the 750 GeV diphoton excess.

Abstract

If decays of a heavy particle S are responsible for the diphoton excess with invariant mass 750 GeV observed at the 13 TeV LHC run, it can be easily accomodated in the Standard Model. Two scenarios are considered: production in gluon fusion through a loop of heavy isosinglet quark(s) and production in photon fusion through a loop of heavy isosinglet leptons. In the second case many heavy leptons are needed or/and they should have large electric charges in order to reproduce experimental data on $\sigma(pp \to SX) \cdot \mathrm{Br}(S \to \gamma \gamma)$.