RG-improved Prediction for 750 GeV Resonance Production at the LHC

We present a renormalization-group (RG) improved prediction for $750$ GeV heavy state production recently seen as the diphoton excess at the LHC. Due to the universality of QCD feature in the threshold region, our result provides reasonable estimate of the K-factor for most existing leading order predictions, independent of the specific nature of the resonance. We consider specifically the spin-$2$ warped Kaluza-Klein graviton model to highlight our calculation. We performed soft gluon resummation near threshold at next-to-next-to-leading logarithmic (NNLL) accuracy together with resumming enhanced corrections from a towers of $\pi^2$ due to analytic continuation. We find the resummation effects are significant. When matching our resummed result to next-to-leading order calculation, we find our improved predictions exceed the leading fixed-order results by about $56\%$ ($K=1.56$) for the LHC energies at 13 TeV and 14 TeV, and about $63\%$ ($K=1.63$) for 8 TeV.