# Reconstruction of top quark pair dilepton decays in electron-positron collisions

## TL;DR

This paper introduces a novel algorithm for reconstructing top quark pair dilepton decays at future electron-positron colliders, accurately determining neutrino momenta using kinematic constraints and likelihood methods.

## Contribution

The paper presents a new numerical algorithm employing multiple kinematic conditions and likelihood discrimination for full event reconstruction in top quark pair dilepton decays.

## Key findings

- Effective reconstruction of neutrino momenta using the proposed method
- Accurate determination of top and W boson kinematic properties
- Validation with generator-level simulation data

## Abstract

A new algorithm is presented to perform the full kinematic reconstruction of top quark pair events produced at future electron-positron colliders in the case of dilepton decays of the $W$ bosons to electrons or muons. The momentum components of the undetected neutrino and anti-neutrino in the event are reconstructed by employing several kinematic conditions comprising a non-linear system of six equations. This system is solved numerically using two independent methods and the selection of the best candidate real solution for each event is determined by a likelihood discriminant. Results are presented for several reconstructed kinematic properties of the $W^\pm$ bosons, top (and anti-top) quarks using generator level information produced at leading order.