Study of the spin of the new boson with up to 25~fb$^{-1}$ of ATLAS data

This note presents a combined study of the spin of the Higgs boson candidate with a mass around 126 GeV which was observed in proton-proton collision data collected at the LHC with the ATLAS detector. Spin studies in the $H \rightarrow \gamma\gamma$, $H \rightarrow WW^\star\rightarrow \ell \nu \ell \nu$ and $H \rightarrow ZZ^\star \rightarrow 4\ell$ decays are combined to discriminate between the Standard Model assignment of $J^P=0^+$ and a specific model of $J^P=2^+$. The dataset corresponds to an integrated luminosity of 20.7 fb$^{-1}$ collected at a centre-of-mass energy of $\sqrt{s} = 8$ TeV. For the $H \rightarrow ZZ^\star \rightarrow 4\ell$ decay mode an additional dataset corresponding to an integrated luminosity of 4.8 fb$^{-1}$ collected at $\sqrt{s} = 7$ TeV is added. The data strongly favour the $J^P=0^+$ hypothesis. The specific $J^P=2^+$ hypothesis is excluded with a confidence level above 99.9%, independently of the assumed contributions of gluon fusion and quark-antiquark annihilation processes in the production of the spin-2 particle.