On the reinterpretation of non-resonant searches for Higgs boson pairs

The detection of production of a pair of Higgs bosons before the end of LHC operation would be a clear evidence of New Physics (NP). As searches for non-resonant production of Higgs pairs are being designed it is of particular importance to be able to conveniently present current experimental results in terms of limits in the most ‘model-independent’ fashion possible. To this end, in this article we provide an analytic parametrization of the differential Higgs-pair production at the LHC in the effective field theory (EFT) extension of the SM. It results from a fit to the theory prediction for the gg → hh cross section at the 13 TeV LHC. Subsequently the resulting formula is used for a reweighing technique that allows to recast exclusion bounds from ATLAS and CMS hh →$ \gamma \gamma b\overline{b} $ searches to any point of the considered EFT parameter space. We demonstrate with a fast simulation of the LHC detectors that with this approach it is possible to cover the continuous EFT parameter space, taking correctly into account the efficiencies of signal selections, without the necessity of rerunning a large number of full detector simulations. Finally, the resulting exclusion bounds are confronted with several explicit models, such as setups with additional scalars, including 2HDM, vector-like fermions, and minimal composite Higgs models, which are mapped to the EFT.