The ATLAS and CMS collaborations, involving teams from CEA/IRFU and CNRS/IN2P3, announced on 4 June 2018 at the LHCP conference the direct observation of the coupling of the quark top to the Higgs boson. Studying the interaction between the Higgs boson and the heaviest elementary particle we know, the quark top, is a way of researching the effects of new physics, which must take over from the standard model.
The results of the analyses, orchestrated by IRFU/DPHP physicists, led to the observation of this rare process and are in agreement with the predictions of the standard model. In the coming years, both experiments will collect much more data and improve the accuracy of their measurements, which could update a deviation from the prediction of the standard model.
Values obtained on the mu_ttH parameter data (observed ttH production rate compared to the expected rate in the standard model), with uncertainties at 1 and 2 sigmas, for the decay channels used as well as for the combination of the results of the CMS experiment. The expected value in the standard model, 1, is represented by the dotted vertical line.
Spectrum of the reconstructed mass of photon pairs after event selection by a multivariate method in the ttH(photon photon) analysis of ATLAS. The peak at 125 GeV corresponds to the signal ttH.
Last update : 06/19 2018 (4464)