Hadronic top quark polarimetry with ParticleNet

Precision studies for top quark physics are a cornerstone of the Large Hadron Collider program. Polarization, probed through decay kinematics, provides a unique tool to scrutinize the top quark across its various production modes and to explore potential new physics effects. However, the top quark m...

Full description

Saved in:
Bibliographic Details
Main Authors: Zhongtian Dong, Dorival Gonçalves, Kyoungchul Kong, Andrew J. Larkoski, Alberto Navarro
Format: Article
Language:English
Published: Elsevier 2025-03-01
Series:Physics Letters B
Online Access:http://www.sciencedirect.com/science/article/pii/S0370269325000747
Tags: Add Tag
No Tags, Be the first to tag this record!
Description
Summary:Precision studies for top quark physics are a cornerstone of the Large Hadron Collider program. Polarization, probed through decay kinematics, provides a unique tool to scrutinize the top quark across its various production modes and to explore potential new physics effects. However, the top quark most often decays hadronically, for which unambiguous identification of its decay products sensitive to top quark polarization is not possible. In this Letter, we introduce a jet flavor tagging method to significantly improve spin analyzing power in hadronic decays, going beyond exclusive kinematic information employed in previous studies. We provide parametric estimates of the improvement from flavor tagging with any set of measured observables and demonstrate this in practice on simulated data using a Graph Neural Network (GNN). We find that the spin analyzing power in hadronic decays can improve by approximately 20% (40%) compared to the kinematic approach, assuming an efficiency of 0.5 (0.2) for the network.
ISSN:0370-2693