Alladi Ramakrishnan Hall

Jet Substructure Analysis for Distinguishing Left- and Right-Handed Couplings of Heavy Neutrino in W' Decay at the HL-LHC

Songshaptak De

Institute of Physics, Bhubaneswar

The search for heavy W' bosons in their decay modes to a lepton and a heavy neutrino offers a promising avenue for probing new physics beyond the Standard Model. This work focuses on such a signature with an energetic lepton plus a fat jet, originating from the heavy neutrino and containing a lepton. We have employed the jet substructure techniques to isolate the embedded lepton as a subjet of the fat jet. The Lepton Subjet Fraction (LSD) and Lepton Mass Drop (LMD) variables constructed from the lepton subjet help in separating the signal region from the background. We further study the polarization properties of the W' coupling to the lepton and heavy neutrino through the decay products of the neutrino. Instead of relying on a specific model, we employ generic couplings and explore the discrimination power. Jet substructure-based angular variables are combined to form BDT scores to obtain a better separation power between the left-chiral (V-A) and right-chiral (V+A) coupling configurations. By using CLs type profile likelihood estimator, we could achieve 1.6 sigma -- 2.8 sigma significance of excluding one coupling configuration in favour of the other.