Evidence for the spin-0 nature of the Higgs boson using ATLAS data

ATLAS COLLABORATION, .... ELODIE TIOUCHICHINE

PHYSICS LETTERS B

ELSEVIER SCIENCE BV

Lugar: Amsterdam; Año: 2013 vol. 726 p. 120 - 144

0370-2693

Studies of the spin and parity quantum numbers of the Higgs boson are presented, based onproton?proton collision data collected by the ATLAS experiment at the LHC. The Standard Modelspin?parity J P = 0+ hypothesis is compared with alternative hypotheses using the Higgs boson decaysH→ γγ, H → ZZ ∗ → 4 and H→ WW ∗ → ν ν, as well as the combination of these channels. Theanalysed dataset corresponds to an integrated luminosity of 20.7 fb−1 collected at a centre?of?mass√energy of s = 8 TeV. For the H → ZZ ∗ → 4 decay mode the dataset corresponding to an integrated√luminosity of 4.6 fb−1 collected at s = 7 TeV is added. The data are compatible with the StandardModel J P = 0+ quantum numbers for the Higgs boson, whereas all alternative hypotheses studiedin this letter, namely some specific J P = 0− , 1+ , 1− , 2+ models, are excluded at confidence levelsabove 97.8%. This exclusion holds independently of the assumptions on the coupling strengths to theStandard Model particles and in the case of the J P = 2+ model, of the relative fractions of gluon?fusionand quark?antiquark production of the spin-2 particle. The data thus provide evidence for the spin-0nature of the Higgs boson, with positive parity being strongly preferred.