Search For The Production Of Dark Matter In Association With Top Quark Pairs In The Single Lepton Final State In Proton Proton Collisions At Sqrt S
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Lepton Photon Interactions At High Energies Lepton Photon 2017 Proceedings Of The 28th International Symposium
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Author : Wei Wang
language : en
Publisher: World Scientific
Release Date : 2020-02-27
Lepton Photon Interactions At High Energies Lepton Photon 2017 Proceedings Of The 28th International Symposium written by Wei Wang and has been published by World Scientific this book supported file pdf, txt, epub, kindle and other format this book has been release on 2020-02-27 with Science categories.
The latest of the 'Lepton Photon' symposium, one of the well-established series of meetings in the high-energy physics community, was successfully organized at the South Campus of Sun Yat-sen University, Guangzhou, China, from August 7-12, 2017, where physicists around the world gathered to discuss the latest advancements in the research field.This proceedings volume of the Lepton Photon 2017 collects contributions by the plenary session speakers and the posters' presenters, which cover the latest results in particle physics, nuclear physics, astrophysics, cosmology, and plans for future facilities.
The Physics Associated With Neutrino Masses
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Author : Diego Aristizabal Sierra
language : en
Publisher: Frontiers Media SA
Release Date : 2020-01-13
The Physics Associated With Neutrino Masses written by Diego Aristizabal Sierra and has been published by Frontiers Media SA this book supported file pdf, txt, epub, kindle and other format this book has been release on 2020-01-13 with categories.
This eBook is a collection of articles from a Frontiers Research Topic. Frontiers Research Topics are very popular trademarks of the Frontiers Journals Series: they are collections of at least ten articles, all centered on a particular subject. With their unique mix of varied contributions from Original Research to Review Articles, Frontiers Research Topics unify the most influential researchers, the latest key findings and historical advances in a hot research area! Find out more on how to host your own Frontiers Research Topic or contribute to one as an author by contacting the Frontiers Editorial Office: frontiersin.org/about/contact.
Search For The Production Of Dark Matter In Association With Top Quark Pairs In The Single Lepton Final State In Proton Proton Collisions At Sqrt S
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Author :
language : en
Publisher:
Release Date : 2015
Search For The Production Of Dark Matter In Association With Top Quark Pairs In The Single Lepton Final State In Proton Proton Collisions At Sqrt S written by and has been published by this book supported file pdf, txt, epub, kindle and other format this book has been release on 2015 with categories.
A search is presented for particle dark matter produced in association with a pair of top quarks in pp collisions at a centre-of-mass energy of s√=8 TeV. The data were collected with the CMS detector at the LHC and correspond to an integrated luminosity of 19.7 fb-1. This search requires the presence of one lepton, multiple jets, and large missing transverse energy. No excess of events is found above the SM expectation, and upper limits are derived on the production cross section. Interpreting the findings in the context of a scalar contact interaction between fermionic dark matter particles and top quarks, lower limits on the interaction scale are set. These limits are also interpreted in terms of the dark matter-nucleon scattering cross sections for the spin-independent scalar operator and they complement direct searches for dark matter particles in the low mass region.
Search For Dark Matter Produced In Association With Top Quarks At The Compact Muon Solenoid
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Author : Victor Shang
language : en
Publisher:
Release Date : 2024
Search For Dark Matter Produced In Association With Top Quarks At The Compact Muon Solenoid written by Victor Shang and has been published by this book supported file pdf, txt, epub, kindle and other format this book has been release on 2024 with categories.
One of the fundamental open questions that cannot be currently explained by the Standard Model is the particle nature of dark matter. Though astrophysical observations provide indirect evidence of its existence, dark matter has not been directly measured so far. However, under certain assumptions, dark matter may be possible to produce and detect at high energy particle colliders like the LHC. This thesis presents a search for dark matter produced in association with top quarks in data collected by the CMS detector at the LHC, corresponding to 138 fb$^{-1}$ of proton-proton collisions at a center-of-mass energy of 13 TeV. Production of dark matter particles in association with both a single top quark and a pair of top quarks are considered. The search is performed in three separate channels depending on the number of leptons in the final state, which include the all hadronic, single lepton, and dileptonic final states. The primary strategy of the search is to look for an excess of events with respect to the background-only prediction in events with a large imbalance in the transverse momentum. The results are interpreted in the context of a simplified model in which either a scalar or pseudoscalar mediator couples to top quarks and to dark matter fermions. Future prospects for improving the search are also discussed.
Search For A Dark Matter Candidate Produced In Association With A Single Top Quark In P Bar P Collisions At Sqrt S
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Author :
language : en
Publisher:
Release Date : 2012
Search For A Dark Matter Candidate Produced In Association With A Single Top Quark In P Bar P Collisions At Sqrt S written by and has been published by this book supported file pdf, txt, epub, kindle and other format this book has been release on 2012 with categories.
We report a new search for dark matter in a data sample of an integrated luminosity of 7.7 fb−1 of Tevatron p{bar p} collisions at √s = 1.96 TeV, collected by the CDF II detector. We search for production of a dark matter candidate, D, in association with a single top quark. We consider the hadronic decay mode of the top quark exclusively, yielding a final state of three jets with missing transverse energy. The data are consistent with the standard model; we thus set 95% confidence level upper limits on the cross section of the process p{bar p} → t + D as a function of the mass of the dark-matter candidate. The limits are approximately 0.5 pb for a dark-matter particle with mass in the range of 0 - 150 GeV/c2.
Search For Dark Matter In Events With Heavy Quarks And Missing Transverse Momentum In Pp Collisions With The Atlas Detector
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Author :
language : en
Publisher:
Release Date : 2015
Search For Dark Matter In Events With Heavy Quarks And Missing Transverse Momentum In Pp Collisions With The Atlas Detector written by and has been published by this book supported file pdf, txt, epub, kindle and other format this book has been release on 2015 with categories.
This article reports on a search for dark matter pair production in association with bottom or top quarks in 20.3 fb-1 of pp collisions collected at √s = 8 TeV by the ATLAS detector at the LHC. Events with large missing transverse momentum are selected when produced in association with high-momentum jets of which one or more are identified as jets containing b-quarks. Final states with top quarks are selected by requiring a high jet multiplicity and in some cases a single lepton. The data are found to be consistent with the Standard Model expectations and limits are set on the mass scale of effective field theories that describe scalar and tensor interactions between dark matter and Standard Model particles. Limits on the dark-matter-nucleon cross-section for spin-independent and spin-dependent interactions are also provided. These limits are particularly strong for low-mass dark matter. Using a simplified model, constraints are set on the mass of dark matter and of a colored mediator suitable to explain a possible signal of annihilating dark matter.
Search For Dark Matter Produced In Association With A Higgs Boson Decaying To Two Bottom Quarks At Atlas
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Author : Yangyang Cheng
language : en
Publisher: Springer
Release Date : 2016-09-29
Search For Dark Matter Produced In Association With A Higgs Boson Decaying To Two Bottom Quarks At Atlas written by Yangyang Cheng and has been published by Springer this book supported file pdf, txt, epub, kindle and other format this book has been release on 2016-09-29 with Science categories.
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.
The Search For The Dark Matter Signature In The Lepton Jet Final State At Sqrt S
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Author : Sergei V. Gleyzer
language : en
Publisher:
Release Date : 2011
The Search For The Dark Matter Signature In The Lepton Jet Final State At Sqrt S written by Sergei V. Gleyzer and has been published by this book supported file pdf, txt, epub, kindle and other format this book has been release on 2011 with categories.
ABSTRACT: The Large Hadron Collider is pushing high energy physics in to a brand new territory. This extraordinary era may bring discoveries of unprecedented magnitude, delivering validation or extreme dissappointment to the physics theories of the previous decades. By colliding particles at more than 3.5 times the center of mass energy of the Tevatron accelerator at the Fermilab National Accelerator Laboratory, the CERN Large Hadron Collider aims to produce particles in the mass range above those that are already known. At the same time, there are exciting possibilities for new physics in the low-mass range that may have gone unnoticed until now. An example of this is a GeV-scale dark sector with a colorful spectrum of new particles. This physics model produces unique signatures of collimated leptons at the Large Hadron Collider energies. In the first part of this work, we describe the interesting astrophysical evidence that motivates a search for lepton jets and focus our attention on a minimal supersymmetric standard model with a GeV-scale dark sector that produces this exciting signature. In the next part of the thesis, we describe a search using the Compact Muon Solenoid (CMS) detector for evidence of dark matter in events containing muonic lepton-jets produced in 7 TeV proton-proton collisions at the Large Hadron Collider. We employ a novel lepton jet algorithm and find no evidence of an excess of such events with respect to the rate predicted by the Standard Model and interpret the null result in terms of a recently developed supersymmetric theory of dark matter. In doing so, we severely constrain the theoretical model and its parameters with the actual data from the Large Hadron Collider. In addition, we report the first observation of double J/Psi production, a new physical process discovery at the next energy frontier.
Search For Production Of Dark Matter In Association With A Higgs Boson Decaying To Bb With The Atlas Detector
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Author : Matthew Baca
language : en
Publisher:
Release Date : 2018
Search For Production Of Dark Matter In Association With A Higgs Boson Decaying To Bb With The Atlas Detector written by Matthew Baca and has been published by this book supported file pdf, txt, epub, kindle and other format this book has been release on 2018 with categories.
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.
Searching For Dark Matter With Boosted Higgs Decays In Proton Proton Collisions At Sqrt S
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Author : Nikola Lazar Whallon
language : en
Publisher:
Release Date : 2018
Searching For Dark Matter With Boosted Higgs Decays In Proton Proton Collisions At Sqrt S written by Nikola Lazar Whallon and has been published by this book supported file pdf, txt, epub, kindle and other format this book has been release on 2018 with categories.
If Dark Matter particles interact with Standard Model particles, it could be possible to pair produce Dark Matter particles in association with a detectable Standard Model particle at a collider such as the LHC. If this associated particle is a Higgs boson, the process is called ``mono-Higgs,'' since the resulting signature is a single Higgs boson balanced by missing energy from the undetected Dark Matter particles. Various Dark Matter models predict that this process could result in very boosted Higgs bosons that, if they decay to a pair of b-quarks, are reconstructed as jets using boosted Higgs tagging techniques. This thesis presents the results of a mono-Higgs search using 79.8 fb−1 of proton-proton collision data collected at a center-of-mass energy of 13 TeV by the ATLAS detector. The observed data are found to be consistent with the expected Standard Model backgrounds. The results are interpreted and exclusion limits are set using a Z' two-Higgs-doublet model where the pseudo-scalar Higgs particle, A, couples to Dark Matter. In order to increase the sensitivity reach of the search, new boosted Higgs tagging techniques are explored and a variable radius track jet Higgs tagging technique is employed.