Jet Energy Scale Studies and the Search for the Standard Model Higgs Boson in the Channel ZH -] Nu Anti-nu B Anti-b at Dï¿1/2

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ISBN 13 :
Total Pages : 193 pages
Book Rating : 4.:/5 (873 download)

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Book Synopsis Jet Energy Scale Studies and the Search for the Standard Model Higgs Boson in the Channel ZH -] Nu Anti-nu B Anti-b at Dï¿1/2 by :

Download or read book Jet Energy Scale Studies and the Search for the Standard Model Higgs Boson in the Channel ZH -] Nu Anti-nu B Anti-b at Dï¿1/2 written by and published by . This book was released on 2006 with total page 193 pages. Available in PDF, EPUB and Kindle. Book excerpt: The D0 experiment is based at the Tevatron, which is currently the world's highest-energy accelerator. The detector comprises three major subsystems: the tracking system, the calorimeter and the muon detector. Jets, seen in the calorimeter, are the most common product of the proton-proton interactions at 2TeV. This thesis is divided into two parts. The first part focuses on jets and describes the derivation of a jet energy scale using p{bar p} → (Z + jets) events as a cross-check of the official D0 jet energy scale (Versions 4.2 and 5.1) which is derived using p{bar p} → [gamma] + jets events. Closure tests were also carried out on the jet energy calibration as a further verification. Jets from b-quarks are commonly produced at D0, readily identified and are a useful physics tool. These require a special correction in the case where the b-jet decays via a muon and a neutrino. Thus a semileptonic correction was also derived as an addition to the standard energy correction for jets. The search for the Higgs boson is one of the largest physics programs at D0. The second part of this thesis describes a search for the Standard Model Higgs boson in the ZH → [nu]{bar {nu}}b{bar b} channel in 52fb−1 of data. The analysis is based on a sequence of event selection criteria optimized on Monte Carlo event samples that simulate four light Higgs boson masses between 105 GeV and 135 GeV and the main backgrounds. For the first time, the data for the analysis are selected using new acoplanarity triggers and the b-quark jets are selected using the D0 neural net b-jet tagging tool. A limit is set for [sigma](p{bar p} → ZH) x Br(H → b{bar b}).

Jet Energy Scale Studies and the Search for the Standard Model Higgs Boson in the Channel ZH {u2192} V $\bar{v}$ B$\bar{b}$ at

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ISBN 13 :
Total Pages : 193 pages
Book Rating : 4.:/5 (16 download)

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Book Synopsis Jet Energy Scale Studies and the Search for the Standard Model Higgs Boson in the Channel ZH {u2192} V $\bar{v}$ B$\bar{b}$ at by :

Download or read book Jet Energy Scale Studies and the Search for the Standard Model Higgs Boson in the Channel ZH {u2192} V $\bar{v}$ B$\bar{b}$ at written by and published by . This book was released on 2006 with total page 193 pages. Available in PDF, EPUB and Kindle. Book excerpt: The D0 experiment is based at the Tevatron, which is currently the world's highest-energy accelerator. The detector comprises three major subsystems: the tracking system, the calorimeter and the muon detector. Jets, seen in the calorimeter, are the most common product of the proton-proton interactions at 2TeV. This thesis is divided into two parts. The first part focuses on jets and describes the derivation of a jet energy scale using p$ar{p}$ → (Z + jets) events as a cross-check of the official D0 jet energy scale (Versions 4.2 and 5.1) which is derived using p$ar{p}$ → ? + jets events. Closure tests were also carried out on the jet energy calibration as a further verification. Jets from b-quarks are commonly produced at D0, readily identified and are a useful physics tool. These require a special correction in the case where the b-jet decays via a muon and a neutrino. Thus a semileptonic correction was also derived as an addition to the standard energy correction for jets. The search for the Higgs boson is one of the largest physics programs at D0. The second part of this thesis describes a search for the Standard Model Higgs boson in the ZH → v$ar{v}$b$ar{b}$ channel in 52fb-1 of data. The analysis is based on a sequence of event selection criteria optimized on Monte Carlo event samples that simulate four light Higgs boson masses between 105 GeV and 135 GeV and the main backgrounds. For the first time, the data for the analysis are selected using new acoplanarity triggers and the b-quark jets are selected using the D0 neural net b-jet tagging tool. A limit is set for ?(p$ar{p}$ → ZH) x Br(H → b$ar{b}$).

Jet Energy Scale Studies and the Search for the Standard Model Higgs Boson in the Channel ZH [rightwards Arrow] Uubb at D'd8

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ISBN 13 :
Total Pages : 0 pages
Book Rating : 4.:/5 (1 download)

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Book Synopsis Jet Energy Scale Studies and the Search for the Standard Model Higgs Boson in the Channel ZH [rightwards Arrow] Uubb at D'd8 by : Lydia Mary Isis Lobo

Download or read book Jet Energy Scale Studies and the Search for the Standard Model Higgs Boson in the Channel ZH [rightwards Arrow] Uubb at D'd8 written by Lydia Mary Isis Lobo and published by . This book was released on 2007 with total page 0 pages. Available in PDF, EPUB and Kindle. Book excerpt:

Search for the Standard Model Higgs Boson in Z H ---] Nu Anti-nu B Anti-b Channel at

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Publisher :
ISBN 13 :
Total Pages : 4 pages
Book Rating : 4.:/5 (873 download)

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Book Synopsis Search for the Standard Model Higgs Boson in Z H ---] Nu Anti-nu B Anti-b Channel at by :

Download or read book Search for the Standard Model Higgs Boson in Z H ---] Nu Anti-nu B Anti-b Channel at written by and published by . This book was released on 2009 with total page 4 pages. Available in PDF, EPUB and Kindle. Book excerpt: We present a search for a low mass Standard Model Higgs boson produced in association with a Z boson decaying invisibly into a pair of neutrinos at a center-of-mass energy of √s = 1.96 TeV with the D0 detector at the Fermilab Tevatron collider. The final state is characterized by the presence of two b-tagged jets from the Higgs boson decay and a large imbalance in the transverse energy of the event. This channel is very powerful because of the large Z → [nu]{anti {nu}} branching ratio, but also has many experimental challenges due to the large multijet background and the absence of visible carged leptons in the final state. We present the result with 5.2 fb−1 of data and discuss the recent improvements in the sensitivity.

The Beauty and the Boost: A Higgs Boson Tale

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Publisher : Springer Nature
ISBN 13 : 3031394429
Total Pages : 250 pages
Book Rating : 4.0/5 (313 download)

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Book Synopsis The Beauty and the Boost: A Higgs Boson Tale by : Brian Moser

Download or read book The Beauty and the Boost: A Higgs Boson Tale written by Brian Moser and published by Springer Nature. This book was released on 2023-09-19 with total page 250 pages. Available in PDF, EPUB and Kindle. Book excerpt: Precision measurements of the Higgs boson’s properties are a powerful tool to look for deviations from the predictions of the Standard Model (SM) of particle physics. The 139/fb of proton-proton collision data which have been collected by the ATLAS experiment during Run 2 of the LHC, offer an opportunity to investigate rare Higgs-boson topologies, which are particularly sensitive to new physics scenarios but experimentally difficult to access. Several such measurements, which target Higgs-boson decays to heavy-flavour quarks, as well as their combinations are presented in this thesis. A novel analysis that measures Higgs-boson production in association with a heavy vector boson V (VH, with V=W,Z) at high energies is presented. Dedicated Higgs-boson reconstruction techniques are applied to reconstruct the highly Lorentz-boosted Higgs-boson decays into pairs of bottom quarks. The measurement is subsequently combined with a VH cross-section measurement at low and intermediate pT(V) to provide a differential cross-section measurement in kinematic fiducial volumes over the largest possible pT(V) range. All cross-section measurements agree with the SM predictions within relative uncertainties that range from 30% to 300%. The results are furthermore interpreted as limits on the parameters of a SM effective field theory. Finally, a combination of measurements of Higgs decays to heavy-flavour quarks is used to experimentally determine that the Higgs-boson coupling to charm quarks is weaker than to bottom quarks, as predicted by the SM. The target audience for the thesis are physicists and physics students, in particular those with a background in high energy physics.

Jet Energy Scale Studies and the Search for the Standard Model Higgs Boson in the Channel ZH [rightwards Arrow] Uubb at D'

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ISBN 13 :
Total Pages : pages
Book Rating : 4.:/5 (93 download)

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Book Synopsis Jet Energy Scale Studies and the Search for the Standard Model Higgs Boson in the Channel ZH [rightwards Arrow] Uubb at D' by :

Download or read book Jet Energy Scale Studies and the Search for the Standard Model Higgs Boson in the Channel ZH [rightwards Arrow] Uubb at D' written by and published by . This book was released on 2007 with total page pages. Available in PDF, EPUB and Kindle. Book excerpt:

Search for the Standard Model Higgs Boson in the P Anti-p ---] ZH ---] Nu Anti-nu B Anti-b Channel

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ISBN 13 :
Total Pages : 7 pages
Book Rating : 4.:/5 (871 download)

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Book Synopsis Search for the Standard Model Higgs Boson in the P Anti-p ---] ZH ---] Nu Anti-nu B Anti-b Channel by :

Download or read book Search for the Standard Model Higgs Boson in the P Anti-p ---] ZH ---] Nu Anti-nu B Anti-b Channel written by and published by . This book was released on 2006 with total page 7 pages. Available in PDF, EPUB and Kindle. Book excerpt: We report a search for the standard model (SM) Higgs boson based on data collected by the D0 experiment at the Fermilab Tevatron Collider, corresponding to an integrated luminosity of 260 pb−1. We study events with missing transverse energy and two acoplanar b-jets, which provide sensitivity to the ZH production cross section in the [nu]{bar [nu]}B{bar b} channel and to WH production, when the lepton from the W → l{nu} decay is undetected. The data are consistent with the SM background expectation, and we set 95% C.L. upper limits on [sigma](p{bar p} → ZN/WH) x B(H → b{bar b}) from 3.4/8.3 to 2.5/6.3 pb, for Higgs masses between 105 and 135 GeV.

A Search for the Standard Model Higgs Boson in Four-jet Final States in Center-of-mass Energies Near 193 GeV with the ALEPH Detector at LEP

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Publisher :
ISBN 13 :
Total Pages : 574 pages
Book Rating : 4.:/5 (89 download)

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Book Synopsis A Search for the Standard Model Higgs Boson in Four-jet Final States in Center-of-mass Energies Near 193 GeV with the ALEPH Detector at LEP by : Stephen R. Armstrong

Download or read book A Search for the Standard Model Higgs Boson in Four-jet Final States in Center-of-mass Energies Near 193 GeV with the ALEPH Detector at LEP written by Stephen R. Armstrong and published by . This book was released on 1998 with total page 574 pages. Available in PDF, EPUB and Kindle. Book excerpt:

Search for the Standard Model Higgs Boson in ZH 2![mu]+[mu]-b$\bar{b}$ Production at DØ and Evidence for the H2!b$\bar{b}$ Decay at the Tevatron

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ISBN 13 :
Total Pages : 176 pages
Book Rating : 4.:/5 (951 download)

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Book Synopsis Search for the Standard Model Higgs Boson in ZH 2![mu]+[mu]-b$\bar{b}$ Production at DØ and Evidence for the H2!b$\bar{b}$ Decay at the Tevatron by :

Download or read book Search for the Standard Model Higgs Boson in ZH 2![mu]+[mu]-b$\bar{b}$ Production at DØ and Evidence for the H2!b$\bar{b}$ Decay at the Tevatron written by and published by . This book was released on 2014 with total page 176 pages. Available in PDF, EPUB and Kindle. Book excerpt: Search for ZH → [mu]+[mu]-b$\bar{b}$ is presented, using a Run 2 dataset with an integrated luminosity of 9.7 fb-1 collected by the DØ detector. Selected events contain at least two reconstructed jets and a Z candidate reconstructed with two opposite-sign charged muons. Random forests of decision trees are trained to distinguish between signal and background events in two orthogonal b-tag samples. The ZH → [mu]+[mu]-b$\bar{b}$b analysis is then combined with ZH → e+e-b$\bar{b}$ analysis. For the combined results of ZH → l+l-b$\bar{b}$b, no Higgs signal is observed, limits are set on the ZH cross-section BR(H→ b$\bar{b}$) for different Higgs masses, from 90 to 150 GeV. For a Standard Model (SM) Higgs boson of mass 125 GeV, the observed cross-section limit is 7.1 times the SM cross-section with an expected sensitivity of 5.1 times the SM cross section. The result of ZH → l+l-b$\bar{b}$b channel has been combined with searches in other Higgs decay channels at the Tevatron, which led to the first evidence of H → b$\bar{b}$.

Search for the Higgs Boson in the $ZH\to\mu^+\mu^- B\bar{b}$ Channel at CDF Using Novel Multivariate Techniques

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ISBN 13 :
Total Pages : pages
Book Rating : 4.:/5 (957 download)

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Book Synopsis Search for the Higgs Boson in the $ZH\to\mu^+\mu^- B\bar{b}$ Channel at CDF Using Novel Multivariate Techniques by :

Download or read book Search for the Higgs Boson in the $ZH\to\mu^+\mu^- B\bar{b}$ Channel at CDF Using Novel Multivariate Techniques written by and published by . This book was released on 2011 with total page pages. Available in PDF, EPUB and Kindle. Book excerpt: We present a search for the Standard Model Higgs Boson using the process $ZH\to\mu^+\mu^- b\bar{b}$. We use a dataset corresponding to 9.2 fb$^{-1}$ of integrated luminosity from proton-antiproton collisions with center-of-mass energy 1.96 TeV at the Fermilab Tevatron, collected with the CDF II detector. This analysis benefits from several new multivariate techniques that have not been used in previous analyses at CDF. We use a multivariate function to select muon candidates, increasing signal acceptance while simultaneously keeping fake rates small. We employ an inclusive trigger selection to further increase acceptance. To enhance signal discrimination, we utilize a multi-layer approach consisting of expert discriminants. This multi-layer discriminant method helps isolate the two main classes of background events, $t\bar{t}$ and $Z$+jets production. It also includes a flavor separator, to distinguish light flavor jets from jets consistent with the decay of a $B$-hadron. Wit h this novel multi-layer approach, we proceed to set limits on the $ZH$ production cross section times branching ratio. For a Higgs boson with mass 115 GeV/$c^2$, we observe (expect) a limit of 8.0 (4.9) times the Standard Model prediction.

A Search for the Standard Model Higgs Boson in the Process $ZH \rightarrow \ell^{+} \ell^{-} B \bar{b}$ in $4.1\unit{fb^{-1}}$ OF CDF~II DATA}

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ISBN 13 :
Total Pages : 204 pages
Book Rating : 4.:/5 (727 download)

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Book Synopsis A Search for the Standard Model Higgs Boson in the Process $ZH \rightarrow \ell^{+} \ell^{-} B \bar{b}$ in $4.1\unit{fb^{-1}}$ OF CDF~II DATA} by :

Download or read book A Search for the Standard Model Higgs Boson in the Process $ZH \rightarrow \ell^{+} \ell^{-} B \bar{b}$ in $4.1\unit{fb^{-1}}$ OF CDF~II DATA} written by and published by . This book was released on 2010 with total page 204 pages. Available in PDF, EPUB and Kindle. Book excerpt: 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{sup ±}, 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{sup ±} and the Z bosons, as predicted by the standard model. The latest experimental averages for the masses of the top quark, W{sup ±} 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{sup {+-}} 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 --> ll−b{bar 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 --> ll−), while the Higgs decays to a bottom anti-bottom quark pair (H --> b{bar 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{bar 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{bar 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 selection applied to isolate ZH --> l+l−b{bar b} candidate events from the data sample, and the advanced techniques employed to maximize the separation of the signal from background processes. Chapters 9 and 10 present the systematic uncertainties affecting our modeling of the data sample and the results of the search. Chapter 11 presents a discussion of ZH --> l+l−b{bar b} in the context of the overall Tevatron efforts to observe a standard model Higgs signal.

Search for the Standard Model Higgs Boson in the Missing Energy Topology with

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Publisher :
ISBN 13 :
Total Pages : 139 pages
Book Rating : 4.:/5 (873 download)

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Book Synopsis Search for the Standard Model Higgs Boson in the Missing Energy Topology with by :

Download or read book Search for the Standard Model Higgs Boson in the Missing Energy Topology with written by and published by . This book was released on 2009 with total page 139 pages. Available in PDF, EPUB and Kindle. Book excerpt: A search for the Standard Model Higgs boson in the missing energy and acoplanar b-jet topology is reported, using an integrated luminosity of 0.93 fb−1 recorded by the D0 detector at the Fermilab Tevatron p{bar p} Collider. The analysis includes signal contributions from p{bar p} → ZH → [nu]{bar {nu}}b{bar b}, as well as from WH production in which the charged lepton from the W boson decay is undetected. Neural networks are used to separate signal from background. In the absence of a signal, limits are set on [sigma](p{bar p} → VH) x B(H → b{bar b}) at the 95% C.L. of 2.6-2.3 pb, for Higgs boson masses in the range 105-135 GeV, where V = W, Z. The corresponding expected limits range from 2.8 to 2.0 pb. Potential improvements to the analysis with an extended dataset totalling 4 fb−1 are also discussed. Essential maintenance related to the increased luminosity and RunIIb upgrade was carried out on the impact parameter (IP) based b-tagging trigger tool and the effect of the changes on the b-tagger's performance was investigated.

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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Publisher :
ISBN 13 :
Total Pages : 204 pages
Book Rating : 4.:/5 (16 download)

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Book Synopsis 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 by :

Download or read book 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 published by . This book was released on 2010 with total page 204 pages. Available in PDF, EPUB and Kindle. Book excerpt: 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 $\ell\nu$ + Jets Final States in 9.7f̃b${̂-1}$ of $p\bar{p}$ Collisions with the D0 Detector

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ISBN 13 :
Total Pages : 40 pages
Book Rating : 4.:/5 (16 download)

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Book Synopsis Search for the Standard Model Higgs Boson in $\ell\nu$ + Jets Final States in 9.7f̃b${̂-1}$ of $p\bar{p}$ Collisions with the D0 Detector by :

Download or read book Search for the Standard Model Higgs Boson in $\ell\nu$ + Jets Final States in 9.7f̃b${̂-1}$ of $p\bar{p}$ Collisions with the D0 Detector written by and published by . This book was released on 2013 with total page 40 pages. Available in PDF, EPUB and Kindle. Book excerpt:

Search for the Standard Model Higgs Boson in the ZH-]vvbb Channel in 5.2 Fb-1 of P-pbar Collisions at Sqrt(s)

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Publisher :
ISBN 13 :
Total Pages : pages
Book Rating : 4.:/5 (873 download)

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Book Synopsis Search for the Standard Model Higgs Boson in the ZH-]vvbb Channel in 5.2 Fb-1 of P-pbar Collisions at Sqrt(s) by :

Download or read book Search for the Standard Model Higgs Boson in the ZH-]vvbb Channel in 5.2 Fb-1 of P-pbar Collisions at Sqrt(s) written by and published by . This book was released on 2009 with total page pages. Available in PDF, EPUB and Kindle. Book excerpt: A search is performed for the standard model Higgs boson in 5.2 fb−1 of p{bar p} collisions at √s = 1.96 TeV, collected with the D0 detector at the Fermilab Tevatron Collider. The final state considered is a pair of b jets and large missing transverse energy, as expected from p{bar p} → ZH → [nu]{bar [nu]}b{bar b} production. The search is also sensitive to the WH → l{nu}b{bar b} channel when the charged lepton is not identified. For a Higgs boson mass of 115 GeV, a limit is set at the 95% C.L. on the cross section multiplied by branching fraction for (p{bar p} → (Z/W)H) x (H → b{bar b}) that is a factor of 3.7 larger than the standard model value, consistent with the factor of 4.6 expected.

Search for the Standard Model Higgs Boson in ZH {u2192} V$\bar{v}$b$\bar{b}$ Channel in P$\bar{p}$ Collisions at {u221A}s

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Publisher :
ISBN 13 :
Total Pages : 188 pages
Book Rating : 4.:/5 (16 download)

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Book Synopsis Search for the Standard Model Higgs Boson in ZH {u2192} V$\bar{v}$b$\bar{b}$ Channel in P$\bar{p}$ Collisions at {u221A}s by :

Download or read book Search for the Standard Model Higgs Boson in ZH {u2192} V$\bar{v}$b$\bar{b}$ Channel in P$\bar{p}$ Collisions at {u221A}s written by and published by . This book was released on 2011 with total page 188 pages. Available in PDF, EPUB and Kindle. Book excerpt: A search for the standard model Higgs boson is performed in 5.2 fb-1 of p$ar{p}$ collisions at p √s = 1.96 TeV, collected with the DØ detector at the Fermilab Tevatron. The final state considered is a pair of b jets with large missing transverse energy, as expected from p$ar{p}$→ ZH → v$ar{v}$b$ar{b}$ production. The search is also sensitive to the WH → lvb$ar{b}$ channel, where the charged lepton is not identified. Boosted decision trees are used to discriminate signal from background. Good agreement is observed between data and expected backgrounds, and, for a Higgs-boson mass of 115 GeV, a limit is set at 95% C.L. on the cross section multiplied by branching fraction of (p$ar{p}$ → (Z/W)H) × (H → b$ar{b}$) that is a factor 4.57 expected and 3.73 observed larger than the value expected from the standard model.

Search for the Standard Model Higgs Boson in ZH {u2192} ?+?-b$\bar{b}$ Production at DØ and Evidence for the H{u2192} B$\bar{b}$ Decay at the Tevatron

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Book Synopsis Search for the Standard Model Higgs Boson in ZH {u2192} ?+?-b$\bar{b}$ Production at DØ and Evidence for the H{u2192} B$\bar{b}$ Decay at the Tevatron by :

Download or read book Search for the Standard Model Higgs Boson in ZH {u2192} ?+?-b$\bar{b}$ Production at DØ and Evidence for the H{u2192} B$\bar{b}$ Decay at the Tevatron written by and published by . This book was released on 2014 with total page 176 pages. Available in PDF, EPUB and Kindle. Book excerpt: Search for ZH → ?+?-b$ar{b}$ is presented, using a Run 2 dataset with an integrated luminosity of 9.7 fb-1 collected by the DØ detector. Selected events contain at least two reconstructed jets and a Z candidate reconstructed with two opposite-sign charged muons. Random forests of decision trees are trained to distinguish between signal and background events in two orthogonal b-tag samples. The ZH → ?+?-b$ar{b}$b analysis is then combined with ZH → e+e-b$ar{b}$ analysis. For the combined results of ZH → l+l-b$ar{b}$b, no Higgs signal is observed, limits are set on the ZH cross-section BR(H→ b$ar{b}$) for different Higgs masses, from 90 to 150 GeV. For a Standard Model (SM) Higgs boson of mass 125 GeV, the observed cross-section limit is 7.1 times the SM cross-section with an expected sensitivity of 5.1 times the SM cross section. The result of ZH → l+l-b$ar{b}$b channel has been combined with searches in other Higgs decay channels at the Tevatron, which led to the first evidence of H → b$ar{b}$.