Investigating kinematic fit to improve sensitivity to Di-Higgs searches with the ATLAS detector

A possibility of improving sensitivity to di-Higgs searches with kinematic fit is investigated using Monte Carlo samples at a centre-of-mass energy of 13 TeV. The decay mode investigated is $b\overline{b} {W} {W}^{*}$ with the final state $b\overline{b} l \nu qq$. An improvement in sensitivity of about 35% compared to the result published by the ATLAS collaboration is observed when a selection criterion on likelihood of $t\overline{t}$ is used. In addition, the hadronic top quark mass reconstruction is found to have better resolution when fitted quantities rather than the measured quantities are used.