First Search For The Standard Model Higgs Boson Using The Semileptonic Decay Channel
DOWNLOAD
Download First Search For The Standard Model Higgs Boson Using The Semileptonic Decay Channel PDF/ePub or read online books in Mobi eBooks. Click Download or Read Online button to get First Search For The Standard Model Higgs Boson Using The Semileptonic Decay Channel book now. This website allows unlimited access to, at the time of writing, more than 1.5 million titles, including hundreds of thousands of titles in various foreign languages. If the content not found or just blank you must refresh this page
First Search For The Standard Model Higgs Boson Using The Semileptonic Decay Channel
DOWNLOAD
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.
First Search For The Standard Model Higgs Boson Using The Semileptonic Decay Channel
DOWNLOAD
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.
First Search For The Standard Model Higgs Boson Using The Semileptonic Decay Channel
DOWNLOAD
Author : Shannon Maura Zelitch
language : en
Publisher:
Release Date : 2010
First Search For The Standard Model Higgs Boson Using The Semileptonic Decay Channel written by Shannon Maura Zelitch 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.
Search For Heavy Standard Model Higgs Boson In The Semileptonic Decay Channel At The Cms Experiment
DOWNLOAD
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.
Search For The Standard Model Higgs Boson In The Decay Channel H To Z Z To 4 Leptons In Pp Collisions At Sqrt S
DOWNLOAD
Author :
language : en
Publisher:
Release Date : 2012
Search For The Standard Model Higgs Boson In The Decay Channel H To Z Z To 4 Leptons In Pp 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.
A search for a Higgs boson in the four-lepton decay channel H to ZZ, with each Z boson decaying to an electron or muon pair, is reported. The search covers Higgs boson mass hypotheses in the range 110 mH
Search For The Higgs Boson In The Zh U2192 V Bar V B Bar B Channel
DOWNLOAD
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
Search For The Standard Model Higgs Boson In The Decay Mode H Ww Lnulnu
DOWNLOAD
Author :
language : en
Publisher:
Release Date : 2009
Search For The Standard Model Higgs Boson In The Decay Mode H Ww Lnulnu written by and has been published by this book supported file pdf, txt, epub, kindle and other format this book has been release on 2009 with categories.
The question of the nature and principles of the universe and our place in it is the driving force of science since Mesopotamian astronomers glanced for the first time at the starry sky and Greek atomism has been formulated. During the last hundred years modern science was able to extend its knowledge tremendously, answering many questions, opening entirely new fields but as well raising many new questions. Particularly Astronomy, Astroparticle Physics and Particle Physics lead the race to answer these fundamental and ancient questions experimentally. Today it is known that matter consists of fermions, the quarks and leptons. Four fundamental forces are acting between these particles, the electromagnetic, the strong, the weak and the gravitational force. These forces are mediated by particles called bosons. Our confirmed knowledge of particle physics is based on these particles and the theory describing their dynamics, the Standard Model of Particles. Many experimental measurements show an excellent agreement between observation and theory but the origin of the particle masses and therefore the electroweak symmetry breaking remains unexplained. The mechanism proposed to solve this issue involves the introduction of a complex doublet of scalar fields which generates the masses of elementary particles via their mutual interactions. This Higgs mechanism also gives rise to a single neutral scalar boson with an unpredicted mass, the Higgs boson. During the last twenty years several experiments have searched for the Higgs boson but so far it escaped direct observation. Nevertheless these studies allow to further constrain its mass range. The last experimental limits on the Higgs mass have been set in 2001 at the LEP collider, an electron positron machine close to Geneva, Switzerland. The lower limit set on the Higgs boson mass is m{sub H}> 114.4 GeV/c2 and remained for many years the last experimental constraint on the Standard Model Higgs Boson due to the shutdown of the LEP collider and the experimental challenges at hadron machines as the Tevatron. This thesis was performed using data from the D0 detector located at the Fermi National Accelerator Laboratory in Batavia, IL. Final states containing two electrons or a muon and a tau in combination with missing transverse energy were studied to search for the Standard Model Higgs boson, utilizing up to 4.2 fb−1 of integrated luminosity. In 2008 the CDF and D0 experiments in a combined effort were able to reach for the first time at a hadron collider the sensitivity to further constrain the possible Standard Model Higgs boson mass range. The research conducted for this thesis played a pivotal role in this effort. Improved methods for lepton identification, background separation, assessment of systematic uncertainties and new decay channels have been studied, developed and utilized. Along with similar efforts at the CDF experiment these improvements led finally the important result of excluding the presence of a Standard Model Higgs boson in a mass range of m{sub H} = 160-170 GeV/c2 at 95% Confidence Level. Many of the challenges and methods found in the present analysis will probably in a similar way be ingredients of a Higgs boson evidence or discovery in the near future, either at the Tevatron or more likely at the soon starting Large Hadron Collider (LHC). Continuing to pursue the Higgs boson we are looking forward to many exciting results at the Tevatron and soon at the LHC. In Chapter 2 an introduction to the Standard Model of particle physics and the Higgs mechanism is given, followed by a brief outline of existing theoretical and experimental constraints on the Higgs boson mass before summarizing the Higgs boson production modes. Chapter 3 gives an overview of the experimental setup. This is followed by a description of the reconstruction of the objects produced in proton-antiproton collisions in Chapter 4 and the necessary calorimeter calibrations in Chapter 5. Chapter 6 follows with an explanation of the phenomenology of the proton-antiproton collisions and the data samples used. In Chapter 7 the search for the Standard Model Higgs boson using a di-electron final state is discussed, followed by the analysis of the final states using muons and hadronic decaying taus in Chapter 8. Finally a short outlook for the prospects of Higgs boson searches is given in Chapter 9.
Search For The Standard Model Higgs Boson In The Decay Mode H U2192 W W U2192 L Vl V
DOWNLOAD
Author :
language : en
Publisher:
Release Date : 2009
Search For The Standard Model Higgs Boson In The Decay Mode H U2192 W W U2192 L Vl V written by and has been published by this book supported file pdf, txt, epub, kindle and other format this book has been release on 2009 with categories.
The question of the nature and principles of the universe and our place in it is the driving force of science since Mesopotamian astronomers glanced for the first time at the starry sky and Greek atomism has been formulated. During the last hundred years modern science was able to extend its knowledge tremendously, answering many questions, opening entirely new fields but as well raising many new questions. Particularly Astronomy, Astroparticle Physics and Particle Physics lead the race to answer these fundamental and ancient questions experimentally. Today it is known that matter consists of fermions, the quarks and leptons. Four fundamental forces are acting between these particles, the electromagnetic, the strong, the weak and the gravitational force. These forces are mediated by particles called bosons. Our confirmed knowledge of particle physics is based on these particles and the theory describing their dynamics, the Standard Model of Particles. Many experimental measurements show an excellent agreement between observation and theory but the origin of the particle masses and therefore the electroweak symmetry breaking remains unexplained. The mechanism proposed to solve this issue involves the introduction of a complex doublet of scalar fields which generates the masses of elementary particles via their mutual interactions. This Higgs mechanism also gives rise to a single neutral scalar boson with an unpredicted mass, the Higgs boson. During the last twenty years several experiments have searched for the Higgs boson but so far it escaped direct observation. Nevertheless these studies allow to further constrain its mass range. The last experimental limits on the Higgs mass have been set in 2001 at the LEP collider, an electron positron machine close to Geneva, Switzerland. The lower limit set on the Higgs boson mass is mH > 114.4 GeV/c2 and remained for many years the last experimental constraint on the Standard Model Higgs Boson due to the shutdown of the LEP collider and the experimental challenges at hadron machines as the Tevatron. This thesis was performed using data from the D0 detector located at the Fermi National Accelerator Laboratory in Batavia, IL. Final states containing two electrons or a muon and a tau in combination with missing transverse energy were studied to search for the Standard Model Higgs boson, utilizing up to 4.2 fb-1 of integrated luminosity. In 2008 the CDF and D0 experiments in a combined effort were able to reach for the first time at a hadron collider the sensitivity to further constrain the possible Standard Model Higgs boson mass range. The research conducted for this thesis played a pivotal role in this effort. Improved methods for lepton identification, background separation, assessment of systematic uncertainties and new decay channels have been studied, developed and utilized. Along with similar efforts at the CDF experiment these improvements led finally the important result of excluding the presence of a Standard Model Higgs boson in a mass range of mH = 160-170 GeV/c2 at 95% Confidence Level. Many of the challenges and methods found in the present analysis will probably in a similar way be ingredients of a Higgs boson evidence or discovery in the near future, either at the Tevatron or more likely at the soon starting Large Hadron Collider (LHC). Continuing to pursue the Higgs boson we are looking forward to many exciting results at the Tevatron and soon at the LHC. In Chapter 2 an introduction to the Standard Model of particle physics and the Higgs mechanism is given, followed by a brief outline of existing theoretical and experimental constraints on the Higgs boson mass before summarizing the Higgs boson production modes. Chapter 3 gives an overview of the experimental setup. This is followed by a description of the reconstruction of the objects produced in proton-antiproton collisions in Chapter 4 and the necessary calorim...
Search For The Standard Model Higgs Boson Produced Through Vector Boson Fusion And Decaying To Mathrm B Bar B
DOWNLOAD
Author :
language : en
Publisher:
Release Date : 2015
Search For The Standard Model Higgs Boson Produced Through Vector Boson Fusion And Decaying To Mathrm B Bar B 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 first search is reported for a standard model Higgs boson (H) that is produced through vector boson fusion and decays to a bottom-quark pair. Two data samples, corresponding to integrated luminosities of 19.8 fb-1 and 18.3 fb-1 of proton-proton collisions at [arrow]"=8 TeV were selected for this channel at the CERN LHC. The observed significance in these data samples for a H2!\mathrm{b\bar{b}}$ signal at a mass of 125 GeV is 2.2 standard deviations, while the expected significance is 0.8 standard deviations. The fitted signal strength [mu]=[sigma]/[sigma]SM=2.8+1.6-1.4. The combination of this result with other CMS searches for the Higgs boson decaying to a b-quark pair yields a signal strength of 1.0"0.4, corresponding to a signal significance of 2.6 standard deviations for a Higgs boson mass of 125 GeV.
Search For The Standard Model Higgs Boson In E Tau Final States
DOWNLOAD
Author :
language : en
Publisher:
Release Date : 2013
Search For The Standard Model Higgs Boson In E Tau Final States written by and has been published by this book supported file pdf, txt, epub, kindle and other format this book has been release on 2013 with categories.
Presented in this dissertation is a search for the standard model (SM) Higgs boson using the DØ detector at Fermilab in Batavia, IL. The SM is a fantastically accurate theory describing the fundamental interactions and particles of the Universe. The only undiscovered particle in the SM is the Higgs boson, which is hypothesized to be responsible for electroweak symmetry breaking and giving mass to all other particles. Considered in this search is the process H + X → e[tau]hjj, where e is an electron, [tau]h is the hadronic decay of a tau, and j is a jet, using p $\bar{p}$ collisions at center of mass energy√s = 1.96 TeV. This search includes three production modes: associated production, gluon fusion and vector boson fusion. It also utilizes two decay channels: H→ [tau][tau] and H → WW. A new technique, dubbed the Global Boosted Decision Tree, is introduced which offers a means of providing continuity to a multivariate search as a function of a particular parameter, in this case, the mass of the Higgs boson. The observed (expected) limit on the ratio of cross section times branching fraction to the SM at 95% confidence level is 14.6 (16.0) at mH = 125 GeV. This result is combined with the related channel H + X → [mu][tau]hjj and produced an observed (expected) limit of 9.0 (11.3) at mH = 125 GeV.