Tagging a boosted top quark with a � final state

Chakraborty, A and De, A and Godbole, RM and Guchait, M (2023) Tagging a boosted top quark with a � final state. In: Physical Review D, 108 (3).

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Abstract

Boosted top quark tagging is one of the challenging, and at the same time exciting, tasks in high energy physics experiments, in particular in the exploration of new physics signals at the LHC. Several techniques have already been developed to tag a boosted top quark in its hadronic decay channel. Recently tagging the same in the semileptonic channel has begun to receive a lot of attention. In the current study, we develop a methodology to tag a boosted top quark (pT>200 GeV) in its semileptonic decay channel with a �-lepton in the final state. In this analysis, the constituents of the top fatjet are reclustered using jet substructure technique to obtain the subjets, and then b- and �- like subjets are identified by applying standard b- and �-jet identification algorithms. We show that the dominant QCD background can be rejected effectively using several kinematic variables of these subjects, such as energy sharing among the jets, invariant mass, transverse mass, N-subjettiness etc., leading to high signal tagging efficiencies. We further assess possible improvements in the results by employing multivariate analysis techniques. We find that using this proposed top-tagger, a signal efficiency of �77 against a background efficiency of �3 can be achieved. We also extend the proposed top-tagger to the case of polarized top quarks by introducing a few additional observables calculated in the rest frame of the b-� system. We comment on how the same methodology will be useful for tagging a boosted heavy BSM particle with a b and � in the final state. © 2023 authors. Published by the American Physical Society. Published by the American Physical Society under the terms of the "https://creativecommons.org/licenses/by/4.0/"Creative Commons Attribution 4.0 International license. Further distribution of this work must maintain attribution to the author(s) and the published article's title, journal citation, and DOI. Funded by SCOAP3.

Item Type:	Journal Article
Publication:	Physical Review D
Publisher:	American Physical Society
Additional Information:	The copyright for this article belongs to authors.
Department/Centre:	Division of Physical & Mathematical Sciences > Centre for High Energy Physics
Date Deposited:	16 Dec 2024 07:14
Last Modified:	16 Dec 2024 07:14
URI:	http://eprints.iisc.ac.in/id/eprint/85533

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