# Comments on the diphoton excess: critical reappraisal of effective field theory interpretations

## Abstract

We consider the diphoton excess observed by ATLAS and CMS using the most up-to-date data and estimate the preferred enhancement in the production rate between 8 TeV and 13 TeV. Within the framework of effective field theory (EFT), we then show that for both spin-0 and spin-2 Standard Model (SM) gauge-singlet resonances, two of the three processes *S* → *ZZ*, *S* → *Z*γ, and *S* → *W W* must occur with a non-zero rate. Moreover, we demonstrate that these branching ratios are highly correlated in the EFT. Couplings of *S* to additional SM states may be constrained and differentiated by comparing the *S* production rates with and without the vector-boson fusion (VBF) cuts. We find that for a given VBF to inclusive production ratio there is maximum rate of *S* to gauge bosons, \( b\overline{b} \), and lighter quark anti-quark pairs. Simultaneous measurements of the width and the VBF ratio may be able to point towards the existence of hidden decays.

### Keywords

Beyond Standard Model Effective field theories### References

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