Search for Dark Matter Produced in Association with a Higgs Boson Decaying to Two Bottom Quarks at ATLAS

Search for Dark Matter Produced in Association with a Higgs Boson Decaying to Two Bottom Quarks at ATLAS

Author: Yangyang Cheng

Publisher: Springer

Published: 2016-09-29

Total Pages: 183

ISBN-13: 331944218X

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This thesis reports on the search for dark matter in data taken with the ATLAS detector at CERN’s Large Hadron Collider (LHC). The identification of dark matter and the determination of its properties are among the highest priorities in elementary particle physics and cosmology. The most likely candidate, a weakly interacting massive particle, could be produced in the high energy proton-proton collisions at the LHC. The analysis presented here is unique in looking for dark matter produced together with a Higgs boson that decays into its dominant decay mode, a pair of b quarks. If dark matter were seen in this mode, we would learn directly about the production mechanism because of the presence of the Higgs boson. This thesis develops the search technique and presents the most stringent production limit to date.


Book Synopsis Search for Dark Matter Produced in Association with a Higgs Boson Decaying to Two Bottom Quarks at ATLAS by : Yangyang Cheng

Download or read book Search for Dark Matter Produced in Association with a Higgs Boson Decaying to Two Bottom Quarks at ATLAS written by Yangyang Cheng and published by Springer. This book was released on 2016-09-29 with total page 183 pages. Available in PDF, EPUB and Kindle. Book excerpt: This thesis reports on the search for dark matter in data taken with the ATLAS detector at CERN’s Large Hadron Collider (LHC). The identification of dark matter and the determination of its properties are among the highest priorities in elementary particle physics and cosmology. The most likely candidate, a weakly interacting massive particle, could be produced in the high energy proton-proton collisions at the LHC. The analysis presented here is unique in looking for dark matter produced together with a Higgs boson that decays into its dominant decay mode, a pair of b quarks. If dark matter were seen in this mode, we would learn directly about the production mechanism because of the presence of the Higgs boson. This thesis develops the search technique and presents the most stringent production limit to date.

Search for Dark Matter Produced in Association with a Higgs Boson Decaying to Two Bottom Quarks in Pp Collisions at S

Search for Dark Matter Produced in Association with a Higgs Boson Decaying to Two Bottom Quarks in Pp Collisions at S

Author:

Publisher:

Published: 2016

Total Pages:

ISBN-13:

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This study reports on a search for dark matter pair production in association with a Higgs boson decaying to a pair of bottom quarks, using data from 20.3 fb–1 of pp collisions at a center-of-mass energy of 8 TeV collected by the ATLAS detector at the LHC. The decay of the Higgs boson is reconstructed as a high-momentum bb¯ system with either a pair of small-radius jets, or a single large-radius jet with substructure. The observed data are found to be consistent with the expected Standard Model backgrounds. Model-independent upper limits are placed on the visible cross sections for events with a Higgs boson decaying into bb¯ and large missing transverse momentum with thresholds ranging from 150 to 400 GeV. Results are interpreted using a simplified model with a Z' gauge boson decaying into different Higgs bosons predicted in a two-Higgs-doublet model, of which the heavy pseudoscalar Higgs decays into a pair of dark matter particles. Exclusion limits are also presented for the mass scales of various effective field theory operators that describe the interaction between dark matter particles and the Higgs boson.


Book Synopsis Search for Dark Matter Produced in Association with a Higgs Boson Decaying to Two Bottom Quarks in Pp Collisions at S by :

Download or read book Search for Dark Matter Produced in Association with a Higgs Boson Decaying to Two Bottom Quarks in Pp Collisions at S written by and published by . This book was released on 2016 with total page pages. Available in PDF, EPUB and Kindle. Book excerpt: This study reports on a search for dark matter pair production in association with a Higgs boson decaying to a pair of bottom quarks, using data from 20.3 fb–1 of pp collisions at a center-of-mass energy of 8 TeV collected by the ATLAS detector at the LHC. The decay of the Higgs boson is reconstructed as a high-momentum bb¯ system with either a pair of small-radius jets, or a single large-radius jet with substructure. The observed data are found to be consistent with the expected Standard Model backgrounds. Model-independent upper limits are placed on the visible cross sections for events with a Higgs boson decaying into bb¯ and large missing transverse momentum with thresholds ranging from 150 to 400 GeV. Results are interpreted using a simplified model with a Z' gauge boson decaying into different Higgs bosons predicted in a two-Higgs-doublet model, of which the heavy pseudoscalar Higgs decays into a pair of dark matter particles. Exclusion limits are also presented for the mass scales of various effective field theory operators that describe the interaction between dark matter particles and the Higgs boson.

Search for Dark Matter Produced in Association with a Higgs Boson Decaying to Two Bottom Quarks in [math Display

Search for Dark Matter Produced in Association with a Higgs Boson Decaying to Two Bottom Quarks in [math Display

Author:

Publisher:

Published: 2016

Total Pages:

ISBN-13:

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Book Synopsis Search for Dark Matter Produced in Association with a Higgs Boson Decaying to Two Bottom Quarks in [math Display by :

Download or read book Search for Dark Matter Produced in Association with a Higgs Boson Decaying to Two Bottom Quarks in [math Display written by and published by . This book was released on 2016 with total page pages. Available in PDF, EPUB and Kindle. Book excerpt:

Search for Dark Matter Produced in Association with a Standard Model Higgs Boson Decaying Into B-quarks Using the Full Run 2 Dataset from the ATLAS Detector

Search for Dark Matter Produced in Association with a Standard Model Higgs Boson Decaying Into B-quarks Using the Full Run 2 Dataset from the ATLAS Detector

Author: ATLAS Collaboration CERN

Publisher:

Published: 2021

Total Pages: 0

ISBN-13:

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Book Synopsis Search for Dark Matter Produced in Association with a Standard Model Higgs Boson Decaying Into B-quarks Using the Full Run 2 Dataset from the ATLAS Detector by : ATLAS Collaboration CERN

Download or read book Search for Dark Matter Produced in Association with a Standard Model Higgs Boson Decaying Into B-quarks Using the Full Run 2 Dataset from the ATLAS Detector written by ATLAS Collaboration CERN and published by . This book was released on 2021 with total page 0 pages. Available in PDF, EPUB and Kindle. Book excerpt:

Search for Associated Production of Dark Matter with a Higgs Boson Decaying to $b\bar{b}$ Or $\gamma\gamma$ at $\sqrt{s}$

Search for Associated Production of Dark Matter with a Higgs Boson Decaying to $b\bar{b}$ Or $\gamma\gamma$ at $\sqrt{s}$

Author:

Publisher:

Published: 2017

Total Pages:

ISBN-13:

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A search for dark matter is performed using events with large missing transverse momentum and a Higgs boson decaying either to a pair of bottom quarks or to a pair of photons. The data from proton-proton collisions at a center-of-mass energy of 13 TeV, collected with the CMS detector at the LHC, correspond to an integrated luminosity of 2.3 inverse-femtobarns. Results are interpreted in the context of a Z'-two-Higgs-doublet model, where a high-mass resonance Z' decays into a pseudoscalar boson A and a CP-even scalar Higgs boson, and the A decays to a pair of dark matter particles. No significant excesses are observed over the background prediction. Combining results from the two decay channels yields exclusion limits in the signal cross section in the m[Z']-m[A] phase space. The observed data exclude, for Z' coupling strength g[Z'] = 0.8 and m[A] = 300 GeV for example, the Z' mass range of 600 to 1860 GeV. This is the first result on a search for dark matter produced in association with a Higgs boson that includes constraints on h to gamma-gamma obtained at sqrt(s) = 13 TeV.


Book Synopsis Search for Associated Production of Dark Matter with a Higgs Boson Decaying to $b\bar{b}$ Or $\gamma\gamma$ at $\sqrt{s}$ by :

Download or read book Search for Associated Production of Dark Matter with a Higgs Boson Decaying to $b\bar{b}$ Or $\gamma\gamma$ at $\sqrt{s}$ written by and published by . This book was released on 2017 with total page pages. Available in PDF, EPUB and Kindle. Book excerpt: A search for dark matter is performed using events with large missing transverse momentum and a Higgs boson decaying either to a pair of bottom quarks or to a pair of photons. The data from proton-proton collisions at a center-of-mass energy of 13 TeV, collected with the CMS detector at the LHC, correspond to an integrated luminosity of 2.3 inverse-femtobarns. Results are interpreted in the context of a Z'-two-Higgs-doublet model, where a high-mass resonance Z' decays into a pseudoscalar boson A and a CP-even scalar Higgs boson, and the A decays to a pair of dark matter particles. No significant excesses are observed over the background prediction. Combining results from the two decay channels yields exclusion limits in the signal cross section in the m[Z']-m[A] phase space. The observed data exclude, for Z' coupling strength g[Z'] = 0.8 and m[A] = 300 GeV for example, the Z' mass range of 600 to 1860 GeV. This is the first result on a search for dark matter produced in association with a Higgs boson that includes constraints on h to gamma-gamma obtained at sqrt(s) = 13 TeV.

Advances in Jet Substructure at the LHC

Advances in Jet Substructure at the LHC

Author: Roman Kogler

Publisher: Springer Nature

Published: 2021-05-10

Total Pages: 287

ISBN-13: 3030728587

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This book introduces the reader to the field of jet substructure, starting from the basic considerations for capturing decays of boosted particles in individual jets, to explaining state-of-the-art techniques. Jet substructure methods have become ubiquitous in data analyses at the LHC, with diverse applications stemming from the abundance of jets in proton-proton collisions, the presence of pileup and multiple interactions, and the need to reconstruct and identify decays of highly-Lorentz boosted particles. The last decade has seen a vast increase in our knowledge of all aspects of the field, with a proliferation of new jet substructure algorithms, calculations and measurements which are presented in this book. Recent developments and algorithms are described and put into the larger experimental context. Their usefulness and application are shown in many demonstrative examples and the phenomenological and experimental effects influencing their performance are discussed. A comprehensive overview is given of measurements and searches for new phenomena performed by the ATLAS and CMS Collaborations. This book shows the impressive versatility of jet substructure methods at the LHC.


Book Synopsis Advances in Jet Substructure at the LHC by : Roman Kogler

Download or read book Advances in Jet Substructure at the LHC written by Roman Kogler and published by Springer Nature. This book was released on 2021-05-10 with total page 287 pages. Available in PDF, EPUB and Kindle. Book excerpt: This book introduces the reader to the field of jet substructure, starting from the basic considerations for capturing decays of boosted particles in individual jets, to explaining state-of-the-art techniques. Jet substructure methods have become ubiquitous in data analyses at the LHC, with diverse applications stemming from the abundance of jets in proton-proton collisions, the presence of pileup and multiple interactions, and the need to reconstruct and identify decays of highly-Lorentz boosted particles. The last decade has seen a vast increase in our knowledge of all aspects of the field, with a proliferation of new jet substructure algorithms, calculations and measurements which are presented in this book. Recent developments and algorithms are described and put into the larger experimental context. Their usefulness and application are shown in many demonstrative examples and the phenomenological and experimental effects influencing their performance are discussed. A comprehensive overview is given of measurements and searches for new phenomena performed by the ATLAS and CMS Collaborations. This book shows the impressive versatility of jet substructure methods at the LHC.

Higgs, Supersymmetry and Dark Matter After Run I of the LHC

Higgs, Supersymmetry and Dark Matter After Run I of the LHC

Author: Béranger Dumont

Publisher: Springer

Published: 2016-09-21

Total Pages: 271

ISBN-13: 3319449567

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This work was nominated as an outstanding PhD thesis by the LPSC, Université Grenoble Alpes, France. The LHC Run 1 was a milestone in particle physics, leading to the discovery of the Higgs boson, the last missing piece of the so-called "Standard Model" (SM), and to important constraints on new physics, which challenge popular theories like weak-scale supersymmetry. This thesis provides a detailed account of the legacy of the LHC Run 1 ≤¥regarding these aspects. First, the SM and the need for its extension are presented in a concise yet revealing way. Subsequently, the impact of the LHC Higgs results on scenarios of new physics is assessed in detail, including a careful discussion of the relevant uncertainties. Two approaches are considered: generic modifications of the Higgs couplings, possibly arising from extended Higgs sectors or higher-dimensional operators; and tests of specific new physics models. Lastly, the implications of the null results of the searches for new physics are discussed with a particular focus on supersymmetric dark matter candidates. Here as well, two approaches are presented: the "simplified models" approach, and recasting by event simulation. This thesis stands out for its educational approach, its clear language and the depth of the physics discussion. The methods and tools presented offer readers essential practical tools for future research.


Book Synopsis Higgs, Supersymmetry and Dark Matter After Run I of the LHC by : Béranger Dumont

Download or read book Higgs, Supersymmetry and Dark Matter After Run I of the LHC written by Béranger Dumont and published by Springer. This book was released on 2016-09-21 with total page 271 pages. Available in PDF, EPUB and Kindle. Book excerpt: This work was nominated as an outstanding PhD thesis by the LPSC, Université Grenoble Alpes, France. The LHC Run 1 was a milestone in particle physics, leading to the discovery of the Higgs boson, the last missing piece of the so-called "Standard Model" (SM), and to important constraints on new physics, which challenge popular theories like weak-scale supersymmetry. This thesis provides a detailed account of the legacy of the LHC Run 1 ≤¥regarding these aspects. First, the SM and the need for its extension are presented in a concise yet revealing way. Subsequently, the impact of the LHC Higgs results on scenarios of new physics is assessed in detail, including a careful discussion of the relevant uncertainties. Two approaches are considered: generic modifications of the Higgs couplings, possibly arising from extended Higgs sectors or higher-dimensional operators; and tests of specific new physics models. Lastly, the implications of the null results of the searches for new physics are discussed with a particular focus on supersymmetric dark matter candidates. Here as well, two approaches are presented: the "simplified models" approach, and recasting by event simulation. This thesis stands out for its educational approach, its clear language and the depth of the physics discussion. The methods and tools presented offer readers essential practical tools for future research.

Search for Dark Matter Produced in Association with a Higgs Boson Decaying to a Pair of Bottom Quarks in Proton-proton Collisions at $\sqrt˜s}

Search for Dark Matter Produced in Association with a Higgs Boson Decaying to a Pair of Bottom Quarks in Proton-proton Collisions at $\sqrt˜s}

Author: Albert M. Sirunyan

Publisher:

Published: 2018

Total Pages:

ISBN-13:

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Book Synopsis Search for Dark Matter Produced in Association with a Higgs Boson Decaying to a Pair of Bottom Quarks in Proton-proton Collisions at $\sqrt˜s} by : Albert M. Sirunyan

Download or read book Search for Dark Matter Produced in Association with a Higgs Boson Decaying to a Pair of Bottom Quarks in Proton-proton Collisions at $\sqrt˜s} written by Albert M. Sirunyan and published by . This book was released on 2018 with total page pages. Available in PDF, EPUB and Kindle. Book excerpt:

Aspects of WIMP Dark Matter Searches at Colliders and Other Probes

Aspects of WIMP Dark Matter Searches at Colliders and Other Probes

Author: Enrico Morgante

Publisher: Springer

Published: 2017-10-05

Total Pages: 212

ISBN-13: 3319676067

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This thesis covers several theoretical aspects of WIMP (weakly interacting massive particles) dark matter searches, with a particular emphasis on colliders. It mainly focuses on the use of effective field theories as a tool for Large Hadron Collider (LHC) searches, discussing in detail the issue of their validity, and on simplified dark matter models, which are receiving a growing attention from the physics community. It highlights the theoretical consistency of simplified models, which is essential in order to correctly exploit their potential and for them to be a common reference when comparing results from different experiments. This thesis is of interest to researchers (both theorists and experimentalists) in the field of dark matter searches, and offers a comprehensive introduction to dark matter and to WIMP searches for students and non-experts.


Book Synopsis Aspects of WIMP Dark Matter Searches at Colliders and Other Probes by : Enrico Morgante

Download or read book Aspects of WIMP Dark Matter Searches at Colliders and Other Probes written by Enrico Morgante and published by Springer. This book was released on 2017-10-05 with total page 212 pages. Available in PDF, EPUB and Kindle. Book excerpt: This thesis covers several theoretical aspects of WIMP (weakly interacting massive particles) dark matter searches, with a particular emphasis on colliders. It mainly focuses on the use of effective field theories as a tool for Large Hadron Collider (LHC) searches, discussing in detail the issue of their validity, and on simplified dark matter models, which are receiving a growing attention from the physics community. It highlights the theoretical consistency of simplified models, which is essential in order to correctly exploit their potential and for them to be a common reference when comparing results from different experiments. This thesis is of interest to researchers (both theorists and experimentalists) in the field of dark matter searches, and offers a comprehensive introduction to dark matter and to WIMP searches for students and non-experts.

Search for Production of Dark Matter in Association with a Higgs Boson Decaying to Bb with the ATLAS Detector

Search for Production of Dark Matter in Association with a Higgs Boson Decaying to Bb with the ATLAS Detector

Author: Matthew Baca

Publisher:

Published: 2018

Total Pages: 0

ISBN-13:

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Using 3.2 fb^-1 of sqrt(s) =13TeV proton-proton data collected in 2015 with the ATLAS detector at the Large Hadron Collider, new limits were imposed on the associated production of Dark Matter with a 125GeV Higgs boson which decays into a pair of b-quarks. The final state of the signal is a pair of b-quark jets and large Missing Transverse Momentum attributed to the DM escaping the detector. The dominant backgrounds were simulated. These were subject to selection requirements to increase signal to background ratio. Three regions were designated based on the number of leptons in the event. 0 lepton events made up the signal region. Events with 1 and 2 leptons were control regions. Similar selection requirements were applied to the control regions as in the signal region, in order to examine a similar phase space. A blinding region was established in the 0 lepton region over the mbb distribution to mask where a reconstructed 125GeV Higgs boson would appear. The control regions and the side bands in the signal region were then fit to the mbb data distribution. Unblinding of the signal region did not result in the discovery of the decay channel, but allowed limits to be imposed.


Book Synopsis Search for Production of Dark Matter in Association with a Higgs Boson Decaying to Bb with the ATLAS Detector by : Matthew Baca

Download or read book Search for Production of Dark Matter in Association with a Higgs Boson Decaying to Bb with the ATLAS Detector written by Matthew Baca and published by . This book was released on 2018 with total page 0 pages. Available in PDF, EPUB and Kindle. Book excerpt: Using 3.2 fb^-1 of sqrt(s) =13TeV proton-proton data collected in 2015 with the ATLAS detector at the Large Hadron Collider, new limits were imposed on the associated production of Dark Matter with a 125GeV Higgs boson which decays into a pair of b-quarks. The final state of the signal is a pair of b-quark jets and large Missing Transverse Momentum attributed to the DM escaping the detector. The dominant backgrounds were simulated. These were subject to selection requirements to increase signal to background ratio. Three regions were designated based on the number of leptons in the event. 0 lepton events made up the signal region. Events with 1 and 2 leptons were control regions. Similar selection requirements were applied to the control regions as in the signal region, in order to examine a similar phase space. A blinding region was established in the 0 lepton region over the mbb distribution to mask where a reconstructed 125GeV Higgs boson would appear. The control regions and the side bands in the signal region were then fit to the mbb data distribution. Unblinding of the signal region did not result in the discovery of the decay channel, but allowed limits to be imposed.