A framework for finding anomalous objects at the LHC

Search for new physics events at the LHC mostly rely on the assumption that the events are characterized in terms of standard-reconstructed objects such as isolated photons, leptons, and jets initiated by QCD-partons. While such strategy works for a vast majority of physics beyond the standard model...

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Main Authors: Amit Chakraborty, Abhishek M. Iyer, Tuhin S. Roy
Format: Article
Language:English
Published: Elsevier 2018-07-01
Series:Nuclear Physics B
Online Access:http://www.sciencedirect.com/science/article/pii/S0550321318301433
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author Amit Chakraborty
Abhishek M. Iyer
Tuhin S. Roy
author_facet Amit Chakraborty
Abhishek M. Iyer
Tuhin S. Roy
author_sort Amit Chakraborty
collection DOAJ
description Search for new physics events at the LHC mostly rely on the assumption that the events are characterized in terms of standard-reconstructed objects such as isolated photons, leptons, and jets initiated by QCD-partons. While such strategy works for a vast majority of physics beyond the standard model scenarios, there are examples aplenty where new physics give rise to anomalous objects (such as collimated and equally energetic particles, decays due to long lived particles etc.) in the detectors, which can not be classified as any of the standard-objects. Varied methods and search strategies have been proposed, each of which is trained and optimized for specific models, topologies, and model parameters. Further, as LHC keeps excluding all expected candidates for new physics, the need for a generic method/tool that is capable of finding the unexpected can not be understated. In this paper, we propose one such method that relies on the philosophy that all anomalous objects are not standard-objects. The anomaly finder, we suggest, simply is a collection of vetoes that eliminate all standard-objects up to a pre-determined acceptance rate. Any event containing at least one anomalous object (that passes all these vetoes), can be identified as a candidate for new physics. Subsequent offline analyses can determine the nature of the anomalous object as well as of the event, paving a robust way to search for these new physics scenarios in a model-independent fashion. Further, since the method relies on learning only the standard-objects, for which control samples are readily available from data, one can build the analysis in an entirely data-driven way.
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spelling doaj.art-69607c5071204946ac69535d37f488ae2022-12-22T01:06:44ZengElsevierNuclear Physics B0550-32132018-07-01932439470A framework for finding anomalous objects at the LHCAmit Chakraborty0Abhishek M. Iyer1Tuhin S. Roy2Theory Center, Institute of Particle and Nuclear Studies, KEK, 1-1 Oho, Tsukuba, Ibaraki 305-0801, Japan; Corresponding author.INFN-Sezione di Napoli, Via Cintia, 80126 Napoli, Italy; Department of Theoretical Physics, Tata Institute of Fundamental Research, Homi Bhabha Road, Colaba, Mumbai 400 005, IndiaDepartment of Theoretical Physics, Tata Institute of Fundamental Research, Homi Bhabha Road, Colaba, Mumbai 400 005, India; Theory Division T-2, Los Alamos National laboratory, Los Alamos, NM 87545, USASearch for new physics events at the LHC mostly rely on the assumption that the events are characterized in terms of standard-reconstructed objects such as isolated photons, leptons, and jets initiated by QCD-partons. While such strategy works for a vast majority of physics beyond the standard model scenarios, there are examples aplenty where new physics give rise to anomalous objects (such as collimated and equally energetic particles, decays due to long lived particles etc.) in the detectors, which can not be classified as any of the standard-objects. Varied methods and search strategies have been proposed, each of which is trained and optimized for specific models, topologies, and model parameters. Further, as LHC keeps excluding all expected candidates for new physics, the need for a generic method/tool that is capable of finding the unexpected can not be understated. In this paper, we propose one such method that relies on the philosophy that all anomalous objects are not standard-objects. The anomaly finder, we suggest, simply is a collection of vetoes that eliminate all standard-objects up to a pre-determined acceptance rate. Any event containing at least one anomalous object (that passes all these vetoes), can be identified as a candidate for new physics. Subsequent offline analyses can determine the nature of the anomalous object as well as of the event, paving a robust way to search for these new physics scenarios in a model-independent fashion. Further, since the method relies on learning only the standard-objects, for which control samples are readily available from data, one can build the analysis in an entirely data-driven way.http://www.sciencedirect.com/science/article/pii/S0550321318301433
spellingShingle Amit Chakraborty
Abhishek M. Iyer
Tuhin S. Roy
A framework for finding anomalous objects at the LHC
Nuclear Physics B
title A framework for finding anomalous objects at the LHC
title_full A framework for finding anomalous objects at the LHC
title_fullStr A framework for finding anomalous objects at the LHC
title_full_unstemmed A framework for finding anomalous objects at the LHC
title_short A framework for finding anomalous objects at the LHC
title_sort framework for finding anomalous objects at the lhc
url http://www.sciencedirect.com/science/article/pii/S0550321318301433
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