Jet Substructure and Multivariate Analysis Aid in Polarization Study of Boosted, Hadronic $W$ Fatjet at the LHC

TL;DR

This paper employs jet substructure techniques and multivariate analysis to determine the polarization states of boosted, hadronic W bosons at the LHC, enhancing the precision of polarization measurements in collider experiments.

Contribution

It introduces a novel approach combining N-subjettiness and Soft Drop methods with template fitting to analyze W boson polarization in boosted jets.

Findings

Successfully distinguished longitudinal and transverse W polarization fractions.

Achieved good accuracy in polarization fraction determination.

Demonstrated effectiveness of jet substructure techniques in polarization studies.

Abstract

Study of polarization of heavy particles is an important branch of research in today's collider studies. The massive $W$ boson has two types of polarization states, which usually are studied via the angular distribution of its decay products. We have studied polarization of hadronic and boosted $W$ boson using jet substructure technique at 14 TeV LHC. Two different methods, viz. N-subjettiness and Soft Drop, were used to find the subjets, which are approximately considered to be the two hadronic decay products of $W$, inside boosted $W$ jets. These subjets were then used to find the distribution of $p_\theta$ and $z_j$ to prepare the templates of longitudinally and transversely polarized $W$. We then used these templates to find the fractions of different $W$ polarization in a mixed sample to a relatively good accuracy.