Speaker
Description
The measurement of Higgs coupling constants is one of the most important goals for Higgs factories. While the couplings of the Higgs boson to the top and bottom quarks have been experimentally confirmed, the coupling to the lighter quark like strange has not yet been observed due to its small decay branching ratio.
We evaluated the measurement accuracy of the Higgs couplings using simulated data based on the ILD detector concept for the International Linear Collider. The analysis focuses on the process $e^+e^- \to Z(\bar{q}q)H$ at a center-of-mass energy of 250 GeV, where we attempt to simultaneously determine the couplings for $H \to b\bar{b}/c\bar{c}/gg/s\bar{s}$ decay modes.To distinguish these processes, we explored two approaches: one primarily utilizing a multi-class deep neural network and the other based on template fitting. In our study, flavor tagging is performed using a Particle Transformer (ParT), which identifies hadrons taking dE/dx and 100 ps time-of-flight as input variables and enables strange tagging. The analysis can be divided into three channels according to Z boson decay modes (neutrino / charged lepton / hadron channel), and we focus on hadron channel in this talk.