Neural-Network Based b-Tagging in the CMS Level 1 Trigger System

The Phase II upgrade of the Compact Muon Solenoid (CMS) detector for the High Luminosity Large Hadron Collider will greatly expand the hardware capabilities of the Level 1 Trigger (L1T) system. With the advent of tracks in the L1T, these upgrades bring the idea of b jet identification within the L1T...

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Main Author: Chambers, Aidan D.
Other Authors: Harris, Philip C.
Format: Thesis
Published: Massachusetts Institute of Technology 2023
Online Access:https://hdl.handle.net/1721.1/151433
https://orcid.org/0000-0003-2780-030X
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author Chambers, Aidan D.
author2 Harris, Philip C.
author_facet Harris, Philip C.
Chambers, Aidan D.
author_sort Chambers, Aidan D.
collection MIT
description The Phase II upgrade of the Compact Muon Solenoid (CMS) detector for the High Luminosity Large Hadron Collider will greatly expand the hardware capabilities of the Level 1 Trigger (L1T) system. With the advent of tracks in the L1T, these upgrades bring the idea of b jet identification within the L1T environment into the realm of feasibility for the first time at CMS. This thesis focuses upon the development of a neural network-based algorithm for the identification of jets originating from bottom quarks in the CMS detector. The algorithm is designed for the timing constraints of the L1T, using seeded cone jet reconstruction of PUPPI algorithm objects as inputs. We present the input data, architecture, and training of the network with performance on simulated 𝑡𝑡¯ events. We then focus on the application of the network towards the 𝐻𝐻 → 𝑏𝑏𝑏𝑏 decay channel, where our neural network-based trigger displays a 12% increase in trigger efficiency for events useful for measuring Higgs self coupling. Finally results are presented for the ongoing progress on implementations of this b-tagging algorithm onto Field Programmable Gate Arrays suitable for the L1T environment. From these results we conclude that b-tagging is possible in the Phase II L1T, a novel achievement that opens the chance to study numerous new physics processes with the first instance of L1T heavy flavor tagging at the LHC.
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spelling mit-1721.1/1514332023-08-01T03:43:59Z Neural-Network Based b-Tagging in the CMS Level 1 Trigger System Chambers, Aidan D. Harris, Philip C. Rankin, Dylan S. Massachusetts Institute of Technology. Department of Physics The Phase II upgrade of the Compact Muon Solenoid (CMS) detector for the High Luminosity Large Hadron Collider will greatly expand the hardware capabilities of the Level 1 Trigger (L1T) system. With the advent of tracks in the L1T, these upgrades bring the idea of b jet identification within the L1T environment into the realm of feasibility for the first time at CMS. This thesis focuses upon the development of a neural network-based algorithm for the identification of jets originating from bottom quarks in the CMS detector. The algorithm is designed for the timing constraints of the L1T, using seeded cone jet reconstruction of PUPPI algorithm objects as inputs. We present the input data, architecture, and training of the network with performance on simulated 𝑡𝑡¯ events. We then focus on the application of the network towards the 𝐻𝐻 → 𝑏𝑏𝑏𝑏 decay channel, where our neural network-based trigger displays a 12% increase in trigger efficiency for events useful for measuring Higgs self coupling. Finally results are presented for the ongoing progress on implementations of this b-tagging algorithm onto Field Programmable Gate Arrays suitable for the L1T environment. From these results we conclude that b-tagging is possible in the Phase II L1T, a novel achievement that opens the chance to study numerous new physics processes with the first instance of L1T heavy flavor tagging at the LHC. S.B. 2023-07-31T19:39:23Z 2023-07-31T19:39:23Z 2023-06 2023-05-18T20:01:29.086Z Thesis https://hdl.handle.net/1721.1/151433 https://orcid.org/0000-0003-2780-030X In Copyright - Educational Use Permitted Copyright retained by author(s) https://rightsstatements.org/page/InC-EDU/1.0/ application/pdf Massachusetts Institute of Technology
spellingShingle Chambers, Aidan D.
Neural-Network Based b-Tagging in the CMS Level 1 Trigger System
title Neural-Network Based b-Tagging in the CMS Level 1 Trigger System
title_full Neural-Network Based b-Tagging in the CMS Level 1 Trigger System
title_fullStr Neural-Network Based b-Tagging in the CMS Level 1 Trigger System
title_full_unstemmed Neural-Network Based b-Tagging in the CMS Level 1 Trigger System
title_short Neural-Network Based b-Tagging in the CMS Level 1 Trigger System
title_sort neural network based b tagging in the cms level 1 trigger system
url https://hdl.handle.net/1721.1/151433
https://orcid.org/0000-0003-2780-030X
work_keys_str_mv AT chambersaidand neuralnetworkbasedbtagginginthecmslevel1triggersystem