The Higgs-like boson spin from the center–edge asymmetry in the diphoton channel at the LHC

We discuss the discrimination of the 125 GeV spin-parity \(0^+\) Higgs-like boson observed at the LHC, decaying into two photons, \(H\rightarrow \gamma \gamma \), against the hypothesis of a minimally coupled \(J^{P}=2^+\) narrow diphoton resonance with the same mass and giving the same total number of signal events under the peak. We apply, as the basic observable of the analysis, the center–edge asymmetry \(A_\mathrm{CE}\) of the cosine of the polar angle of the produced photons in the diphoton rest frame to distinguish between the tested spin hypotheses. We show that the center–edge asymmetry \(A_\mathrm{CE}\) should provide a strong discrimination between the possibilities of spin-0 and spin-2 with graviton-like couplings, depending on the fraction of \(q\bar{q}\) production of the spin-2 signal, reaching \(\text {CL}_s<10^{-6}\) for \(f_{qq}=0\). Indeed, the \(A_\mathrm{CE}\) has the potential to do better than existing analyses for \(f_{qq}<0.4\).