Search For Heavy Standard Model Higgs Boson In The Semileptonic Decay Channel At The Cms Experiment
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Search For Heavy Standard Model Higgs Boson In The Semileptonic Decay Channel At The Cms Experiment
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Author :
language : en
Publisher:
Release Date : 2012
Search For Heavy Standard Model Higgs Boson In The Semileptonic Decay Channel At The Cms Experiment 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.
First Search For The Standard Model Higgs Boson Using The Semileptonic Decay Channel
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Author :
language : en
Publisher:
Release Date : 2010
First Search For The Standard Model Higgs Boson Using The Semileptonic Decay Channel written by and has been published by this book supported file pdf, txt, epub, kindle and other format this book has been release on 2010 with categories.
This dissertation presents the first search for the standard model Higgs boson (H) in decay topologies containing a muon, an imbalance in transverse momentum (E{sub T}) and jets, using p{bar p} collisions at √s = 1.96 TeV with an integrated luminosity of 4.3 fb−1 recorded with the D0 detector at the Fermilab Tevatron Collider. This analysis is sensitive primary to contributions from Higgs bosons produced through gluon fusion, with subsequent decay H → WW → [mu][nu]jj where W represents a real or virtual W boson. In the absence of signal, limits are set at 95% confidence on the production and decay of the standard model Higgs boson for M{sub H} in the range of 115-200 GeV. For M{sub H} = 165 GeV, the observed and expected limits are factors of 11.2 larger than the standard model value. Combining this channel with e[nu]jj final states and including earlier data to increase the integrated luminosity to 5.4 fb−1 produces observed(expected) limits of 5.5(3.8) times the standard model value.
Search For The Higgs Boson In The Zh U2192 V Bar V B Bar B Channel
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Author :
language : en
Publisher:
Release Date : 2010
Search For The Higgs Boson In The Zh U2192 V Bar V B Bar B Channel written by and has been published by this book supported file pdf, txt, epub, kindle and other format this book has been release on 2010 with categories.
In the Standard Model of particle physics, the Higgs boson generates elementary particle masses. Current theoretical and experimental constraints lead to a Higgs boson mass between 114.4 and 158 GeV with 95% confidence level. Moreover, Tevatron has recently excluded the mass ranges between 100 and 109 GeV, 158 and 175 GeV with 95% confidence level. These results gives a clear indication to search for a Higgs boson at low mass. The D0 detector is located near Chicago, at the Tevatron, a proton-antiproton collider with an energy in the center of mass of 1.96 TeV. The topic of this thesis is the search for a Higgs boson in association with a Z boson. This channel is sensitive to low mass Higgs boson (135 GeV) which has a branching ratio H → bb varies between 50% and 90% in this mass range. The decay channel ZH → v$ar{v}$b$ar{b}$ studied has in the final state 2 heavy-flavor jets and some missing transverse energy due to escaping neutrinos. The heavy-flavor jets identification ('b-tagging') is done with a new algorithm (SLTNN) developed specifically for semi-leptonic decay of b quarks. The Higgs boson search analysis was performed with 3 fbsup-1
First Search For The Standard Model Higgs Boson Using The Semileptonic Decay Channel
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Author :
language : en
Publisher:
Release Date : 2010
First Search For The Standard Model Higgs Boson Using The Semileptonic Decay Channel written by and has been published by this book supported file pdf, txt, epub, kindle and other format this book has been release on 2010 with categories.
This dissertation presents the first search for the standard model Higgs boson (H) in decay topologies containing a muon, an imbalance in transverse momentum (ET) and jets, using p$ar{p}$ collisions at √s = 1.96 TeV with an integrated luminosity of 4.3 fb-1 recorded with the D0 detector at the Fermilab Tevatron Collider. This analysis is sensitive primary to contributions from Higgs bosons produced through gluon fusion, with subsequent decay H → WW → ??jj where W represents a real or virtual W boson. In the absence of signal, limits are set at 95% confidence on the production and decay of the standard model Higgs boson for MH in the range of 115-200 GeV. For MH = 165 GeV, the observed and expected limits are factors of 11.2 larger than the standard model value. Combining this channel with e?jj final states and including earlier data to increase the integrated luminosity to 5.4 fb-1 produces observed(expected) limits of 5.5(3.8) times the standard model value.
Phenomena Beyond The Standard Model What Do We Expect For New Physics To Look Like
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Author : Roman Pasechnik
language : en
Publisher: Frontiers Media SA
Release Date : 2020-09-03
Phenomena Beyond The Standard Model What Do We Expect For New Physics To Look Like written by Roman Pasechnik 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 2020-09-03 with Science 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 A Vector Like Quark T Decaying Into Top Higgs In Single Production Mode In Full Hadronic Final State Using Cms Data Collected At 8 Tev
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Author : José David Ruiz Alvarez
language : en
Publisher:
Release Date : 2015
Search For A Vector Like Quark T Decaying Into Top Higgs In Single Production Mode In Full Hadronic Final State Using Cms Data Collected At 8 Tev written by José David Ruiz Alvarez 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.
During 2012, the Large Hadron Collider (LHC) has delivered proton-proton collisions at 8 TeV center of mass energy to the ATLAS and CMS experiments. These two experiments have been designed to discover the Higgs boson and to search for new particles predicted by several theoretical models, as supersymmetry. The Higgs boson has been discovered by ATLAS and CMS experiments on July, 4th of 2012, starting a new era of discoveries in particle physics domain. With the confirmation of the existence of the Higgs boson, searches for new physics involving this boson are of major interest. In particular, data can be used to look for new massive particles that decay into the Higgs boson accompanied with other particles of the standard model. One expected signature is a Higgs boson produced with a top quark, the two heaviest particles in the standard model. The standard model predicts a cross section of top-Higgs production, then any enhancement of their associated production will be a clear signature of physics beyond the standard model. In addition, the existence of physics beyond the standard model can also be reflected by resonances that decay into a top-quark and a Higgs boson. In the first part of my work I describe the theoretical and experimental foundations of the standard model, as well as the experimental device. In the same theoretical chapter, I also discuss the formulation of an extension of the standard model. In addition, I describe a feasibility study of a search of one of the particles predicted by such model. The second part contains the realization of the search for a top partner, T_, within the CMS experiment. This top partner is a new particle very similar to the standard model top quark, but much heavier, that can decay into a top quark and a Higgs boson. The analysis looks for this particle in the full hadronic final state, where the Higgs boson decays into two b-quarks and the top quark decays into three standard model quarks, a b and two light quarks. In this channel, I reconstruct its mass from the identification of all its decay products. As a result of the analysis, I show the limits on the T_ production cross section from the number of observed events in the specific signature.
The Standard Model Higgs Boson Discovery Potential In The Decay Channel H Zz Superscript 4 Mu With The Cms Detector
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Author : Alexey Alexandrovich Drozdetskiy
language : en
Publisher:
Release Date : 2007
The Standard Model Higgs Boson Discovery Potential In The Decay Channel H Zz Superscript 4 Mu With The Cms Detector written by Alexey Alexandrovich Drozdetskiy and has been published by this book supported file pdf, txt, epub, kindle and other format this book has been release on 2007 with categories.
ABSTRACT: The Compact Muon Solenoid (CMS) is a general purpose detector at the Large Hadron Collider (LHC) currently under construction at CERN with start-up date in 2008. The putative Higgs boson is the most plausible solution for the mystery of mass in the Standard Model of elementary particles and its discovery is one of the prime goals for the LHC. Higgs boson search. Our research presents an optimized strategy for a Higgs boson search in its four-muon decay channel, H--> ZZ[superscript*]--> 4[mu], also known as a golden decay channel. The method automatically ensures an optimal signal-to-background ratio for any mass, at which the Higgs boson might appear. The most important theoretical and instrumental systematic errors are taken into account and our search was conducted in a broad range of possible Higgs boson masses. Muon reconstruction. We developed an algorithm for a fast and efficient muon track segment reconstruction in Cathode Strip Chambers. Designed to be CPU-efficient, the algorithm is specifically targeted for High Level Trigger purposes. The segment-finding efficiency and the spatial resolution attainable with the proposed algorithm and the required CPU time were validated using the cosmic ray data taken by the CMS in 2006. The results of validation showed the efficiency and spatial resolution attainable with the algorithm are well within the High Level Trigger requirements and the algorithm's timing performance is by far superior to all algorithms previously used in CMS.
Search For The Standard Model Higgs Boson In The H Zz L L Qq Decay Channel At Cms
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Author : Francesco Pandolfi
language : en
Publisher:
Release Date : 2013-09-30
Search For The Standard Model Higgs Boson In The H Zz L L Qq Decay Channel At Cms written by Francesco Pandolfi and has been published by this book supported file pdf, txt, epub, kindle and other format this book has been release on 2013-09-30 with categories.
A Search For The Standard Model Higgs Boson In The Process Zh U2192 L L B Bar B In 4 1 Fb 1 Of Cdf Ii Data
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Author :
language : en
Publisher:
Release Date : 2010
A Search For The Standard Model Higgs Boson In The Process Zh U2192 L L B Bar B In 4 1 Fb 1 Of Cdf Ii Data written by and has been published by this book supported file pdf, txt, epub, kindle and other format this book has been release on 2010 with categories.
The standard model of particle physics provides a detailed description of a universe in which all matter is composed of a small number of fundamental particles, which interact through the exchange of force - carrying gauge bosons (the photon, W ±, Z and gluons). The organization of the matter and energy in this universe is determined by the effects of three forces; the strong, weak, and electromagnetic. The weak and electromagnetic forces are the low energy manifestations of a single electro-weak force, while the strong force binds quarks into protons and neutrons. The standard model does not include gravity, as the effect of this force on fundamental particles is negligible. Four decades of experimental tests, spanning energies from a few electron-volts (eV) up to nearly two TeV, confirm that the universe described by the standard model is a reasonable approximation of our world. For example, experiments have confirmed the existence of the top quark, the W± and the Z bosons, as predicted by the standard model. The latest experimental averages for the masses of the top quark, W± and Z are respectively 173.1 ± 0.6(stat.) ± 1.1(syst.), 80.399 ± 0.023 and 91.1876 ± 0.0021 GeV/c2. The SM is a gauge field theory of zero mass particles. However, the SM is able to accommodate particles with non-zero mass through the introduction of a theoretical Higgs field which permeates all of space. Fermions gain mass through interactions with this field, while the longitudinal components of the massive W± and Z are the physical manifestations of the field itself. Introduction of the Higgs field, directly leads to the predicted existence of an additional particle, the Higgs boson. The Higgs boson is the only particle of the standard model that has not been observed, and is the only unconfirmed prediction of the theory. The standard model describes the properties of the Higgs boson in terms of its mass, which is a free parameter in the theory. Experimental evidence suggests that the Higgs mass has a value between 114.4 and 186 GeV/c2. Particles with a mass in this range can be produced in collisions of less massive particles accelerated to near the speed of light. Currently, one of only a few machines capable of achieving collision energies large enough to potentially produce a standard model Higgs boson is the Tevatron proton-antiproton collider located at Fermi National Accelerator Laboratory in Batavia, Illinois. This dissertation describes the effort to observe the standard model Higgs in Tevatron collisions recorded by the Collider Detector at Fermilab (CDF) II experiment in the ZH →l+l-b$ar{b}$ production and decay channel. In this process, the Higgs is produced along with a Z boson which decays to a pair of electrons or muons (Z →l+l-), while the Higgs decays to a bottom anti-bottom quark pair (H → b$ar{b}$). A brief overview of the standard model and Higgs theory is presented in Chapter 2. Chapter 3 explores previous searches for the standard model Higgs at the Tevatron and elsewhere. The search presented in this dissertation expands upon the techniques and methods developed in previous searches. The fourth chapter contains a description of the Tevatron collider and the CDF II detector. The scope of the discussion in Chapter 4 is limited to the experimental components relevant to the current ZH →l+l-b$ar{b}$ search. Chapter 5 presents the details of object reconstruction; the methods used to convert detector signals into potential electrons, muons or quarks. Chapter six describes the data sample studied for the presence of a ZH →l+l-b$ar{b}$ signal and details the techniques used to model the data. The model accounts for both signal and non-signal processes (backgrounds) which are expected to contribute to the observed event sample. Chapters 7 and 8 summarize the event selectio...
Search For The Standard Model Higgs Boson In The H Zz L L Qq Decay Channel At Cms
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Author : Francesco Pandolfi
language : en
Publisher: Springer Science & Business Media
Release Date : 2013-08-15
Search For The Standard Model Higgs Boson In The H Zz L L Qq Decay Channel At Cms written by Francesco Pandolfi and has been published by Springer Science & Business Media this book supported file pdf, txt, epub, kindle and other format this book has been release on 2013-08-15 with Science categories.
The theoretical foundations of the Standard Model of elementary particles relies on the existence of the Higgs boson, a particle which has been revealed for the first time by the experiments run at the Large Hadron Collider (LHC) in 2012. As the Higgs boson is an unstable particle, its search strategies were based on its decay products. In this thesis, Francesco Pandolfi conducted a search for the Higgs boson in the H → ZZ → l + l - qq Decay Channel with 4.6 fb -1 of 7 TeV proton-proton collision data collected by the Compact Muon Solenoid (CMS) experiment. The presence of jets in the final state poses a series of challenges to the experimenter: both from a technical point of view, as jets are complex objects and necessitate of ad-hoc reconstruction techniques, and from an analytical one, as backgrounds with jets are copious at hadron colliders, therefore analyses must obtain high degrees of background rejection in order to achieve competitive sensitivity. This is accomplished by following two directives: the use of an angular likelihood discriminant, capable of discriminating events likely to originate from the decay of a scalar boson from non-resonant backgrounds, and by using jet parton flavor tagging, selecting jets compatible with quark hadronization and discarding jets more likely to be initiated by gluons. The events passing the selection requirements in 4.6 fb -1 of data collected by the CMS detector are examined, in the search of a possible signal compatible with the decay of a heavy Higgs boson. The thesis describes the statistical tools and the results of this analysis. This work is a paradigm for studies of the Higgs boson with final states with jets. The non-expert physicists will enjoy a complete and eminently readable description of a proton-proton collider analysis. At the same time, the expert reader will learn the details of the searches done with jets at CMS.