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Search For The Standard Model Higgs Boson In Association With A W Boson At
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Book Synopsis Search for the Standard Model Higgs Boson in Association with a W Boson at by :
Download or read book Search for the Standard Model Higgs Boson in Association with a W Boson at written by and published by . This book was released on 2013 with total page 274 pages. Available in PDF, EPUB and Kindle. Book excerpt: I present a search for the standard model Higgs boson, H, produced in association with a W boson in data events containing a charged lepton (electron or muon), missing energy, and two or three jets. The data analysed correspond to 9.7 fb-1 of integrated luminosity collected at a center-of-momentum energy of √s = 1.96 TeV with the D0 detector at the Fermilab Tevatron p$ar{p}$ collider. This search uses algorithms to identify the signature of bottom quark production and multivariate techniques to improve the purity of H → b$ar{b}$ production. We validate our methodology by measuring WZ and ZZ production with Z → b$ar{b}$ and find production rates consistent with the standard model prediction. For a Higgs boson mass of 125 GeV, we determine a 95% C.L. upper limit on the production of a standard model Higgs boson of 4.8 times the standard model Higgs boson production cross section, while the expected limit is 4.7 times the standard model production cross section. I also present a novel method for improving the energy resolution for charged particles within hadronic signatures. This is achieved by replacing the calorimeter energy measurement for charged particles within a hadronic signature with the tracking momentum measurement. This technique leads to a ̃20% improvement in the jet energy resolution, which yields a ̃7% improvement in the reconstructed dijet mass width for H → b$ar{b}$ events. The improved energy calculation leads to a ̃5% improvement in our expected 95% C.L. upper limit on the Higgs boson production cross section.
Book Synopsis Search for the Standard Model Higgs Boson in Association with a W Boson at by : Savanna Marie Shaw
Download or read book Search for the Standard Model Higgs Boson in Association with a W Boson at written by Savanna Marie Shaw and published by . This book was released on 2013 with total page 242 pages. Available in PDF, EPUB and Kindle. Book excerpt: I present a search for the standard model Higgs boson, H, produced in association with a W boson in data events containing a charged lepton (electron or muon), missing energy, and two or three jets. The data analysed correspond to 9.7 fb-1 of integrated luminosity collected at a center-of-momentum energy of √s = 1.96 TeV with the D0 detector at the Fermilab Tevatron p$\bar{p}$ collider. This search uses algorithms to identify the signature of bottom quark production and multivariate techniques to improve the purity of H → b$\bar{b}$ production. We validate our methodology by measuring WZ and ZZ production with Z → b$\bar{b}$ and find production rates consistent with the standard model prediction. For a Higgs boson mass of 125 GeV, we determine a 95% C.L. upper limit on the production of a standard model Higgs boson of 4.8 times the standard model Higgs boson production cross section, while the expected limit is 4.7 times the standard model production cross section. I also present a novel method for improving the energy resolution for charged particles within hadronic signatures. This is achieved by replacing the calorimeter energy measurement for charged particles within a hadronic signature with the tracking momentum measurement. This technique leads to a ~ 20% improvement in the jet energy resolution, which yields a ~ 7% improvement in the reconstructed dijet mass width for H → b$\bar{b}$ events. The improved energy calculation leads to a ~ 5% improvement in our expected 95% C.L. upper limit on the Higgs boson production cross section.
Book Synopsis Search for Standard Model Higgs Boson Production in Association with a W Boson at CDF. by :
Download or read book Search for Standard Model Higgs Boson Production in Association with a W Boson at CDF. written by and published by . This book was released on 2012 with total page pages. Available in PDF, EPUB and Kindle. Book excerpt: We present a search for the standard model Higgs boson production in association with a $W$ boson in proton-antiproton collisions ($p\bar{p}\rightarrow W\̂pm H \rightarrow \ell\nu b\bar{b}$) at a center of mass energy of 1.96 TeV. The search employs data collected with the CDF II detector which correspond to an integrated luminosity of approximately 2.7 fb${̂-1}$. We recorded this data with two kinds of triggers. The first kind required high-p$_T$ charged leptons and the second required both missing transverse energy and jets. The search selects events consistent with a signature of a single lepton ($e\̂pm/\mu\̂pm$), missing transverse energy, and two jets. Jets corresponding to bottom quarks are identified with a secondary vertex tagging method and a jet probability tagging method. Kinematic information is fed in an artificial neural network to improve discrimination between signal and background. The search finds that both the observed number of events and the neural network output distributions are consistent with the standard model background expectations, and sets 95% confidence level upper limits on the production cross section times branching ratio. The limits are expressed as a ratio to the standard model production rate. The limits range from 3.6 (4.3 expected) to 61.1 (43.2 expected) for Higgs masses from 100 to 150 GeV/$c{̂2}$, respectively.
Book Synopsis A Search for the Standard Model Higgs Boson Produced in Association with a W Boson by : Martin J. Frank
Download or read book A Search for the Standard Model Higgs Boson Produced in Association with a W Boson written by Martin J. Frank 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 a standard model Higgs boson produced in association with a W boson using data collected with the CDF II detector from proton/antiproton collisions at a center of mass energy of 1.96 TeV. The search is performed in the WH channel where the W boson decays leptonically and the Higgs boson decays to a bottom/antibottom quark pair. The two quarks usually fragment into two jets, but sometimes a third jet can be produced via gluon radiation, so we have increased the standard two-jet sample by including events that contain three jets. We reconstruct the Higgs boson using two or three jets depending on the kinematics of the event. We find an improvement in our search sensitivity using the larger sample together with this multijet reconstruction technique. Our data show no evidence of a Higgs boson, so we set 95% confidence level upper limits on the WH production rate. We set limits between 3.36 and 28.7 times the standard model prediction for Higgs boson masses ranging from 100 to 150 GeV/c^2.
Book Synopsis A Search for the Standard Model Higgs Boson Produced in Association with a $W$ Boson by :
Download or read book A Search for the Standard Model Higgs Boson Produced in Association with a $W$ Boson written by and published by . This book was released on 2011 with total page 177 pages. Available in PDF, EPUB and Kindle. Book excerpt: We present a search for a standard model Higgs boson produced in association with a W boson using data collected with the CDF II detector from p$ar{p}$ collisions at √s = 1.96 TeV. The search is performed in the WH → lvb$ar{b}$ channel. The two quarks usually fragment into two jets, but sometimes a third jet can be produced via gluon radiation, so we have increased the standard two-jet sample by including events that contain three jets. We reconstruct the Higgs boson using two or three jets depending on the kinematics of the event. We find an improvement in our search sensitivity using the larger sample together with this multijet reconstruction technique. Our data show no evidence of a Higgs boson, so we set 95% confidence level upper limits on the WH production rate. We set limits between 3.36 and 28.7 times the standard model prediction for Higgs boson masses ranging from 100 to 150 GeV/c2.
Book Synopsis Search for the Standard Model Higgs Boson Associated with a W Boson Using Matrix Element Technique in the CDF Detector at the Tevatron by :
Download or read book Search for the Standard Model Higgs Boson Associated with a W Boson Using Matrix Element Technique in the CDF Detector at the Tevatron written by and published by . This book was released on 2010 with total page 195 pages. Available in PDF, EPUB and Kindle. Book excerpt: In this thesis a direct search for the Standard Model Higgs boson production in association with a W boson at the CDF detector in the Tevatron is presented. This search contributes predominantly in the region of low mass Higgs region, when the mass of Higgs boson is less than about 135 GeV. The search is performed in a final state where the Higgs boson decays into two b quarks, and the W boson decays leptonically, to a charged lepton (it can be an electron or a muon) and a neutrino. This work is organized as follows. Chapter 2 gives an overview of the Standard Model theory of particle physics and presents the SM Higgs boson search results at LEP, and the Tevatron colliders, as well as the prospects for the SM Higgs boson searches at the LHC. The dataset used in this analysis corresponds to 4.8 fb−1 of integrated luminosity of p{bar p} collisions at a center of mass energy of 1.96 TeV. That is the luminosity acquired between the beginning of the CDF Run II experiment, February 2002, and May 2009. The relevant aspects, for this analysis, of the Tevatron accelerator and the CDF detector are shown in Chapter 3. In Chapter 4 the particles and observables that make up the WH final state, electrons, muons, E{sub T}, and jets are presented. The CDF standard b-tagging algorithms to identify b jets, and the neural network flavor separator to distinguish them from other flavor jets are also described in Chapter 4. The main background contributions are those coming from heavy flavor production processes, such as those coming from Wbb, Wcc or Wc and tt. The signal and background signatures are discussed in Chapter 5 together with the Monte CArlo generators that have been used to simulate almost all the events used in this thesis. WH candidate events have a high-p{sub T} lepton (electron or muon), high missing transverse energy, and two or more than two jets in the final state. Chapter 6 describes the event selection applied in this analysis and the method used to estimate the background contribution. The Matrix Element method, that was successfully used in the single t0p discovery analysis and many other analyses within the CDF collaboration, is the multivariate technique used in this thesis to discriminate signal from background events. With this technique is possible to calculate a probability for an event to be classified as signal or background. These probabilities are then combined into a discriminant function called the Event Probability Discriminant, EPD, which increases the sensitivity of the WH process. This method is described in detail in Chapter 7. As no evidence for the signal has been found, the results obtained with this work are presented in Chapter 8 in terms of exclusion regions as a function of the mass of the Higgs boso, taking into account the full systematics. The conclusions of this work to obtain the PhD are presnted in Chapter 9.
Book Synopsis Search for the Standard Model Higgs Boson Produced in Association with a W Boson in the Isolated-track Charged-lepton Channel Using the Collider Detector at Fermilab by : Adrian Buzatu
Download or read book Search for the Standard Model Higgs Boson Produced in Association with a W Boson in the Isolated-track Charged-lepton Channel Using the Collider Detector at Fermilab written by Adrian Buzatu and published by . This book was released on 2011 with total page pages. Available in PDF, EPUB and Kindle. Book excerpt: The Higgs boson is the only elementary particle predicted by the Standard Model (SM) that has not yet been observed experimentally. If it exists, it explains the spontaneous electroweak symmetry breaking and the origin of mass for gauge bosons and fermions. We test the validity of the SM by performing a search for the associated production of a Higgs boson and a W boson in the channel where the Higgs boson decays to a bottom-antibottom quark pair and the W boson decays to a charged lepton and a neutrino (the WH channel). We study a dataset of proton-antiproton collisions at a centre-of-mass energy of 1.96 TeV provided by the Tevatron accelerator, corresponding to an integrated luminosity of 5.7 inverse femtobarns, and recorded using the Collider Detector at Fermilab (CDF). We select events consistent with the signature of exactly one charged lepton (electron or muon), missing transverse energy due to the undetected neutrino (MET) and two collimated streams ...
Book Synopsis A Beauty-ful Boson by : Giulia Di Gregorio
Download or read book A Beauty-ful Boson written by Giulia Di Gregorio and published by Springer Nature. This book was released on 2023-01-01 with total page 229 pages. Available in PDF, EPUB and Kindle. Book excerpt: The analysis described in this thesis is the search for the Higgs boson, decaying into bb pair, in the associated production with a vector boson, in the extreme Higgs boson transverse momentum region where the Higgs boson is reconstructed using the large-R jet technique. The use of the large-R jets allows to add a part of the phase space unexplored so far, which is particularly sensitive to possible new physics. The analysed data have been collected at LHC by the ATLAS detector between 2015 and 2018 at a centre-of-mass energy of √s = 13 TeV. The same dataset has been used to perform the differential pp → ZH and pp → WH cross-section measurements used to extract the information on the Higgs couplings and to put limits on Beyond the Standard Model effects. Furthermore the analysis has been re-used to perform a cross-section measurement of the diboson ZZ and WZ processes because the diboson and the Higgs processes have a similar topology. For the first time the ZZ(bb) and WZ(bb) cross-sections are measured at √s = 13 TeV and the observed cross-section measurements are consistent with the Standard Model predictions.
Book Synopsis Search for Standard Model Higgs Boson Production in Association with a W Boson Using a Neural Network by :
Download or read book Search for Standard Model Higgs Boson Production in Association with a W Boson Using a Neural Network written by and published by . This book was released on 2009 with total page pages. Available in PDF, EPUB and Kindle. Book excerpt: We present a search for standard model Higgs boson production in association with a W boson in proton-antiproton collisions (p{bar p} → W{sup {+-}}H → l[nu]b{bar b}) at a center of mass energy of 1.96 TeV. The search employs data collected with the CDF II detector that correspond to an integrated luminosity of approximately 1.9 fb−1. We select events consistent with a signature of a single charged lepton (e{sup {+-}}/[mu]{sup {+-}}), missing transverse energy, and two jets. Jets corresponding to bottom quarks are identified with a secondary vertex tagging method, a jet probability tagging method, and a neural network filter. We use kinematic information in an artificial neural network to improve discrimination between signal and background compared to previous analyses. The observed number of events and the neural network output distributions are consistent with the standard model background expectations, and we set 95% confidence level upper limits on the production cross section times branching fraction ranging from 1.2 to 1.1 pb or 7.5 to 102 times the standard model expectation for Higgs boson masses from 110 to 150 GeV/c2, respectively.
Book Synopsis Search for the Standard Model Higgs Boson in the H → ZZ → l + l - qq Decay Channel at CMS by : Francesco Pandolfi
Download or read book Search for the Standard Model Higgs Boson in the H → ZZ → l + l - qq Decay Channel at CMS written by Francesco Pandolfi and published by Springer Science & Business Media. This book was released on 2013-08-15 with total page 137 pages. Available in PDF, EPUB and Kindle. Book excerpt: 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.
Book Synopsis The Higgs Boson by : Scientific American Editors
Download or read book The Higgs Boson written by Scientific American Editors and published by Scientific American. This book was released on 2012-09-30 with total page 467 pages. Available in PDF, EPUB and Kindle. Book excerpt: The Higgs Boson: Searching for the God Particle by the Editors of Scientific American Updated 2017 Edition! For the fifth anniversary of one of the biggest discoveries in physics, we’ve updated this eBook to include our continuing analysis of the discovery, of the questions it answers and those it raises. As the old adage goes, where there’s smoke, there’s fire. Where there is effect, there must be cause. The planet Neptune was found in 1846 because the mathematics of Newton's laws, when applied to the orbit of Uranus, said some massive body had to be there. Astronomers eventually found it, using the best telescopes available to peer into the sky. This same logic is applied to the search for the Higgs boson. One consequence of the prevailing theory of physics, called the Standard Model, is that there has to be some field that gives particles their particular masses. With that there has to be a corresponding particle, made by creating waves in the field, and this is the Higgs boson, the so-called God particle. This eBook chronicles the search – and demonstrates the power of a good theory. Based on the Standard Model, physicists believed something had to be there, but it wasn't until the Large Hadron Collider was built that anyone could see evidence of the Higgs – and finally in July 2012, they did. A Higgs-like particle was found near the energies scientists expected to find it. Now, armed with better evidence and better questions, the scientific process continues. This eBook gathers the best reporting and analysis from Scientific American to explain that process – the theories, the search, the ongoing questions. In essence, everything you need to know to separate Higgs from hype.
Book Synopsis Search for the Standard Model Higgs Boson in Its Associated Production with a W Vector Boson in Pp Collisions at {u221A}s by :
Download or read book Search for the Standard Model Higgs Boson in Its Associated Production with a W Vector Boson in Pp Collisions at {u221A}s written by and published by . This book was released on 2013 with total page 275 pages. Available in PDF, EPUB and Kindle. Book excerpt: In this dissertation, results from a search for the Standard Model (SM) Higgs boson is shown. The SM is the theoretical framework which describes particles of matter and force carrier gauge bosons. To solve the mass problem in the SM, the Higgs mechanism was introduced in 1963. The Higgs mechanism causes an electroweak symmetry breaking and a new massive scalar boson was postulated. This particle is the Higgs boson. A search for the Higgs boson has been ongoing at the Tevatron where protons and antiprotons were allowed to collide at a center-of-mass energy of 1.96 TeV. For a low mass Higgs, that is a Higgs with a mass lower than 135 GeV, the dominant decay mode is Higgs to a pair of b-quarks (H →b $ar{b}$ ). This work concentrated on a Higgs whose mass is in the range of 100 150 GeV, with a W vector boson produced with the Higgs boson. The final state chosen is the one which contains a lepton a neutrino and a pair of b-quarks. This study used data provided by the DZERO experiment. Results presented here are the outcome of analyzing 5.3 fb-1 of data from RunII period. The analysis used different techniques to increase the sensitivity of the study. Data were subdivided based on lepton flavor, number of jets in sample, jets identified as b-jets and dates of collected data. A multivariate analysis technique based on boosted decision trees were used to separate signal from background processes, physical and instrumental. A good agreement between data and simulated events was observed.
Book Synopsis Search for the Standard Model Higgs Boson in Its Associated Production with a W Vector Boson in Pp Collisions at P S by :
Download or read book Search for the Standard Model Higgs Boson in Its Associated Production with a W Vector Boson in Pp Collisions at P S written by and published by . This book was released on 2013 with total page 275 pages. Available in PDF, EPUB and Kindle. Book excerpt: In this dissertation, results from a search for the Standard Model (SM) Higgs boson is shown. The SM is the theoretical framework which describes particles of matter and force carrier gauge bosons. To solve the mass problem in the SM, the Higgs mechanism was introduced in 1963. The Higgs mechanism causes an electroweak symmetry breaking and a new massive scalar boson was postulated. This particle is the Higgs boson. A search for the Higgs boson has been ongoing at the Tevatron where protons and antiprotons were allowed to collide at a center-of-mass energy of 1.96 TeV. For a low mass Higgs, that is a Higgs with a mass lower than 135 GeV, the dominant decay mode is Higgs to a pair of b-quarks (H 2! $\bar{b}$). This work concentrated on a Higgs whose mass is in the range of 100 150 GeV, with a W vector boson produced with the Higgs boson. The final state chosen is the one which contains a lepton a neutrino and a pair of b-quarks. This study used data provided by the DZERO experiment. Results presented here are the outcome of analyzing 5.3 fb-1 of data from RunII period. The analysis used different techniques to increase the sensitivity of the study. Data were subdivided based on lepton flavor, number of jets in sample, jets identified as b-jets and dates of collected data. A multivariate analysis technique based on boosted decision trees were used to separate signal from background processes, physical and instrumental. A good agreement between data and simulated events was observed.
Book Synopsis Search for the Standard Model Higgs Boson Produced in Association with a W Boson in the Isolated-track Charged-lepton Channel Using the Collider Detector at Fermilab by :
Download or read book Search for the Standard Model Higgs Boson Produced in Association with a W Boson in the Isolated-track Charged-lepton Channel Using the Collider Detector at Fermilab written by and published by . This book was released on 2011 with total page 208 pages. Available in PDF, EPUB and Kindle. Book excerpt: The Higgs boson is the only elementary particle predicted by the Standard Model (SM) that has not yet been observed experimentally. If it exists, it explains the spontaneous electroweak symmetry breaking and the origin of mass for gauge bosons and fermions. We test the validity of the SM by performing a search for the associated production of a Higgs boson and a W boson in the channel where the Higgs boson decays to a bottom-antibottom quark pair and the W boson decays to a charged lepton and a neutrino (the WH channel). We study a dataset of proton-antiproton collisions at a centre-of-mass energy √s = 1.96 TeV provided by the Tevatron accelerator, corresponding to an integrated luminosity of 5.7 fb−1, and recorded using the Collider Detector at Fermilab (CDF).We select events consistent with the signature of exactly one charged lepton (electron or muon), missing transverse energy due to the undetected neutrino (MET) and two collimated streams of particles (jets), at least one of which is required to be identified as originating from a bottom quark. We improve the discrimination of Higgs signal from backgrounds through the use of an artificial neural network. Using a Bayesian statistical inference approach, we set for each hypothetical Higgs boson mass in the range 100-150 GeV/c2 with 5 GeV/c2 increments a 95% credibility level (CL) upper limit on the ratio between the Higgs production cross section times branching fraction and the SM prediction. Our main original contributions are the addition of a novel charged lepton reconstruction algorithm with looser requirements (ISOTRK) with respect the electron or muon tight criteria (TIGHT), as well as the introduction of a novel trigger-combination method that allows to maximize the event yield while avoiding trigger correlations and that is used for the ISOTRK category. The ISOTRK candidate is a high-transverse-momentum good-quality track isolated from other activity in the tracking system and not required to match a calorimeter cluster, as for a tight electron candidate, or an energy deposit in the muon detector, as for a tight muon candidate. The ISOTRK category recovers real charged leptons that otherwise would be lost in the non-instrumented regions of the detector. This allows the reconstruction of more W boson candidates, which in turn increases the number of reconstructed WH signal candidate events, and therefore improves the sensitivity of the WH search. For the TIGHT charged lepton categories, we employ charged-lepton-dedicated triggers to improve the rate of WH signal acceptance during data taking. Since there is no ISOTRK-dedicated trigger at CDF, for the ISOTRK charged lepton category we employ three MET-plus-jets-based triggers. For each trigger we first identify the jet selection where the trigger efficiency is flat with respect to jet information (transverse energy and direction of motion in the transverse plane for the two jets in the event) and then we parametrize the trigger efficiency as a function of trigger MET. On an event-by-event basis, for each trigger we compute a trigger efficiency as a function of trigger parametrization, trigger MET, jet information, trigger prescale and information about whether the trigger is defined or not. For the ISOTRK category we combine the three triggers using a novel method, which allows the combination of any number of triggers in order to maximize the event yield while avoiding trigger correlations. On an event-by-event basis, only the trigger with the largest efficiency is used. By avoiding a logical 'OR' between triggers, the loss in the yield of events accepted by the trigger combination is compensated by a smaller and easier-to-compute corresponding systematic uncertainty. The addition of the ISOTRK charged lepton category to the TIGHT category produces an increase of 33% in the WH signal yield and a decrease of 15.5% to 19.0% in the median expected 95% CL cross-section upper limits across the entire studied Higgs mass interval. The improvement in analysis sensitivity is smaller than the improvement in signal yield because the ISOTRK category has a smaller signal over background ratio than the TIGHT category, due to the looser ISOTRK reconstruction criteria. The observed (median expected) 95% CL SM Higgs upper limits on cross section times branching ratio vary between 2.39 x SM (2.73 x SM) for a Higgs mass of 100 GeV/c2 to 31.1 x SM (31.2 x SM) for a Higgs mass of 150 GeV/c2, while the value for a 115 GeV/c2 Higgs boson is that of 5.08 x SM (3.79 x SM). The novel trigger combination method is already in use by several CDF analyses. It is applicable to any analysis that uses triggers based on MET and jets, such as supersymmetry searches at the ATLAS and CMS experiments at the Large Hadron Collider. In its most general form, the method can be used by any analysis that combines any number of different triggers.
Book Synopsis Search for the Standard Model Higgs Boson Produced in Association with a $Z$ Boson in $p\bar{p}$ Collisions at $\sqrt{s} by :
Download or read book Search for the Standard Model Higgs Boson Produced in Association with a $Z$ Boson in $p\bar{p}$ Collisions at $\sqrt{s} written by and published by . This book was released on 2012 with total page pages. Available in PDF, EPUB and Kindle. Book excerpt: We present a search for the standard model Higgs boson produced in association with a Z boson, using up to 7.9 fb−1 of integrated luminosity from p{bar p} collisions collected with the CDF II detector. We utilize several novel techniques, including multivariate lepton selection, multivariate trigger parametrization, and a multi-stage signal discriminant consisting of specialized functions trained to distinguish individual backgrounds. By increasing acceptance and enhancing signal discrimination, these techniques have significantly improved the sensitivity of the analysis above what was expected from a larger dataset alone. We observe no significant evidence for a signal, and we set limits on the ZH production cross section. For a Higgs boson with mass 115 GeV/c2, we expect (observe) a limit of 3.9 (4.8) times the standard model predicted value, at the 95% credibility level.
Book Synopsis Search for Standard Model Higgs Boson Production in Association with a $W$ Boson Using a Matrix Element Technique at CDF in $p\bar{p}$ Collisions at $\sqrt{s} by :
Download or read book Search for Standard Model Higgs Boson Production in Association with a $W$ Boson Using a Matrix Element Technique at CDF in $p\bar{p}$ Collisions at $\sqrt{s} written by and published by . This book was released on 2011 with total page pages. Available in PDF, EPUB and Kindle. Book excerpt: This paper presents a search for standard model Higgs boson production in association with a W boson using events recorded by the CDF experiment in a dataset corresponding to an integrated luminosity of 5.6 fb−1. The search is performed using a matrix element technique in which the signal and background hypotheses are used to create a powerful discriminator. The discriminant output distributions for signal and background are fit to the observed events using a binned likelihood approach to search for the Higgs boson signal. We find no evidence for a Higgs boson, and 95% confidence level (C.L.) upper limits are set on?(p{bar p} → WH) x?(H → b{bar b}). The observed limits range from 3.5 to 37.6 relative to the standard model expectation for Higgs boson masses between m{sub H} = 100 GeV/c2 and m{sub H} = 150 GeV/c2. The 95% C.L. expected limit is estimated from the median of an ensemble of simulated experiments and varies between 2.9 and 32.7 relative to the production rate predicted by the standard model over the Higgs boson mass range studied.
Book Synopsis Search for the Standard Model Higgs Boson Produced in Association with a Standard W Or a Z Boson and Decaying to Bottom Quarks by :
Download or read book Search for the Standard Model Higgs Boson Produced in Association with a Standard W Or a Z Boson and Decaying to Bottom Quarks written by and published by . This book was released on 2014 with total page 49 pages. Available in PDF, EPUB and Kindle. Book excerpt: A search for the standard model Higgs boson (H) decaying to b b-bar when produced in association with a weak vector boson (V) is reported for the following channels: W(mu nu)H, W(e nu)H, W(tau nu)H, Z(mu mu)H, Z(e e)H, and Z(nu nu)H. The search is performed in data samples corresponding to integrated luminosities of up to 5.1 inverse femtobarns at sqrt(s) = 7 TeV and up to 18.9 inverse femtobarns at sqrt(s) = 8 TeV, recorded by the CMS experiment at the LHC. An excess of events is observed above the expected background with a local significance of 2.1 standard deviations for a Higgs boson mass of 125 GeV, consistent with the expectation from the production of the standard model Higgs boson. The signal strength corresponding to this excess, relative to that of the standard model Higgs boson, is 1.0 +/- 0.5./abstract