An improved measurement of the mass of the Higgs boson is derived from a combined fit to the reconstructed invariant mass spectra of the decay channels H→γγ and H→ZZ*→4ℓ. The analysis uses the pp collision data sample recorded by the ATLAS experiment at the CERN Large Hadron Collider at center-of-mass energies of 7 TeV and 8 TeV, corresponding to an integrated luminosity of 25 fb−1. The measured value of the Higgs boson mass is mH = 125.36 ± 0.37(stat) ± 0.18(syst) GeV. Detailed measurements of Higgs' boson properties are a part of strategy that will determine whether this recently discovered particle fits in the Standard Model of particle physics or represents a hint of new physics beyond this model.
Institute of Physics is a co-founder of the ATLAS experiment. Our staff has participated on development, construction and operation of path detectors and calorimeter. Both devices have played an important part in the Higgs boson discovery and are essential for detailed measurement of its parameters.