Reconstruction of Chargino Decays to $\tau H$ with Missing Transverse Momentum

Tau lepton ($\tau$) is usually the least investigated of all lepton flavors, due to its large missing transverse momentum caused by the undetected tau neutrino in the decay of $\tau$, which makes accurate reconstruction of $\tau$ challenging. Since some R-parity violating supersymmetry models hint at a preference for $\tau$ flavor in lepton decays from charginos, it may be helpful to special accommodate this $\tau$ preference. As part of the ATLAS experiment at the CERN Large Hadron Collider, this research investigates the reconstruction of chargino pairs with R-parity violating decays to $\tau \tau H H$ ($H$ refers to Higgs boson) with special consideration of the missing transverse momentum. This research improves the reconstruction of charginos by separating the missing transverse momentum vector into two components and reverse projecting them onto the directions of the visible particles from $\tau$ decays. This improved reconstruction method leads to an improvement of about 15% in pairing accuracy is achieved across chargino masses from 250 GeV to 1500 GeV using truth-level simulations, and the reconstructed chargino mass peaks closer to the expected mass. Using reconstructed simulations, this method shows improvements in pairing efficiency of about 30% on average, also with the shift in the peak. Cuts are also optimized for this reconstruction method.