Search for the Standard Model Higgs boson produced in association with a pair of top quarks and decaying into a bb-pair in the single lepton channel at √s
Search for the Standard Model Higgs boson produced in association with a pair of top quarks and decaying into a bb-pair in the single lepton channel at √s

Author: Matteo Mantoani

Publisher:

Published: 2017

Total Pages:

ISBN-13:

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This thesis presents a search for Standard Model Higgs boson produced in association with top quark pairs, ttH. The analysis uses 13.2 fb-1 of pp collision data at √s = 13 TeV collected in 2015 and 2016 with the ATLAS detector at the LHC. The considered decay mode for the Higgs boson is H->bb and the single lepton decay channel (electron or muon) for the tt pair. The sensitivity of this channel is improved by an event categorisation according to the jet multiplicity and the number of jets containing a b-hadron decay. Multivariate techniques are used to distinguish the signa...

Artificial Intelligence For High Energy Physics
Artificial Intelligence For High Energy Physics

Author: Paolo Calafiura

Publisher: World Scientific

Published: 2022-01-05

Total Pages: 829

ISBN-13: 9811234043

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The Higgs boson discovery at the Large Hadron Collider in 2012 relied on boosted decision trees. Since then, high energy physics (HEP) has applied modern machine learning (ML) techniques to all stages of the data analysis pipeline, from raw data processing to statistical analysis. The unique requirements of HEP data analysis, the availability of high-quality simulators, the complexity of the data structures (which rarely are image-like), the control of uncertainties expected from scientific measurements, and the exabyte-scale datasets require the development of HEP-specific ML techniques. While these developments proceed at full speed along many paths, the nineteen reviews in this book offer a self-contained, pedagogical introduction to ML models' real-life applications in HEP, written by some of the foremost experts in their area.

Search for the Standard Model Higgs Boson Decaying Into $ B\overline{b} $ Produced in Association with Top Quarks Decaying Hadronically in Pp Collisions at $ \sqrt{s}
Search for the Standard Model Higgs Boson Decaying Into $ B\overline{b} $ Produced in Association with Top Quarks Decaying Hadronically in Pp Collisions at $ \sqrt{s}

Author:

Publisher:

Published: 2016

Total Pages: 51

ISBN-13:

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In this paper, a search for Higgs boson production in association with a pair of top quarks ($ t\overline{t} $H) is performed, where the Higgs boson decays to $ b\overline{b} $ , and both top quarks decay hadronically. The data used correspond to an integrated luminosity of 20.3 fb -1 of pp collisions at √s = 8 TeV collected with the ATLAS detector at the Large Hadron Collider. The search selects events with at least six energetic jets and uses a boosted decision tree algorithm to discriminate between signal and Standard Model background. The dominant multijet background is estimated using a dedicated data-driven technique. For a Higgs boson mass of 125 GeV, an upper limit of 6.4 (5.4) times the Standard Model cross section is observed (expected) at 95% confidence level. The best-fit value for the signal strength is [mu] = 1.6 ± 2.6 times the Standard Model expectation for mH = 125 GeV. Combining all $ t\overline{t}$H searches carried out by ATLAS at √s = 8 and 7 TeV, an observed (expected) upper limit of 3.1 (1.4) times the Standard Model expectation is obtained at 95% confidence level, with a signal strength [mu] = 1.7 ± 0.8.

Search for the Standard Model Higgs Boson Produced in Association with a Vector Boson and Decaying Into a Tau Pair in Pp Collisions at S
Search for the Standard Model Higgs Boson Produced in Association with a Vector Boson and Decaying Into a Tau Pair in Pp Collisions at S

Author:

Publisher:

Published: 2016

Total Pages:

ISBN-13:

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A search for the standard model Higgs boson produced in association with a vector boson with the decay H → ?? is presented. The data correspond to 20.3 fb-1 of integrated luminosity from proton-proton collisions at √s=8 TeV recorded by the ATLAS experiment at the LHC during 2012. The data agree with the background expectation, and 95% confidence-level upper limits are placed on the cross section of this process. The observed (expected) limit, expressed in terms of the signal strength ? = ?/?SM for mH = 125 GeV, is ?

Search for the Standard Model Higgs Boson Produced in Association with Tt and Decaying Into Bb at 8 TeV with the ATLAS Detector Using the Matrix Element Method
Search for the Standard Model Higgs Boson Produced in Association with Tt and Decaying Into Bb at 8 TeV with the ATLAS Detector Using the Matrix Element Method

Author:

Publisher:

Published: 2015

Total Pages:

ISBN-13:

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A search for the Standard Model Higgs boson produced in association with a pair of top quarks (ttH) is presented. The analysis uses 20.3 fb-1 of pp collision data at √s = 8 TeV, collected with the ATLAS detector at the Large Hadron Collider during 2012. The search is designed for the H → bb decay mode and is performed in the single lepton (electrons or muons) decay channel of the top quark pair. In order to improve the sensitivity of the search, events are categorised according to their jet and b-tagged jet multiplicities into nine different analysis regions. A matrix element method is deve...