Measurement of at the 250 GeV ILC

The  process with the subsequent decay of the Higgs boson is studied, where both Z bosons are reconstructed in the final states with two jets. The analysis is performed using Monte Carlo data samples obtained with detailed ILD detector simulation assuming an integrated luminosity of 2 ab–1, beam polarizations of 
, and center-of-mass energy of  GeV for the electron–positron International Linear Collider being currently designed. The analysis is repeated for the case of two 0.9 ab–1 data samples with polarizations . Contributions of the potential background processes are studied using all available ILD MC event samples. The largest background comes from the  process supplemented by an energetic photon produced by initial state radiation. To suppress this background, we require that at least one of the Z bosons decays to b-jets. To reduce the jet reconstruction uncertainties the  variable is used, where  GeV. The  distributions are obtained for the studied signal and backgrounds to estimate the expected accuracy of the  measurement. The accuracy is 22% for the option of the single polarization sample described above and deteriorate to 24% in case of the sample with two polarizations. The proposed method can be applied at any future  collider.