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Measurement Of The Single Top Quark Production Cross Section In 196 Tev Proton Antiproton Collisions
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Book Synopsis Measurement of the Single Top Production Cross Section in Proton-antiproton Collisions at 1.96 TeV. by :
Download or read book Measurement of the Single Top Production Cross Section in Proton-antiproton Collisions at 1.96 TeV. written by and published by . This book was released on 2010 with total page 342 pages. Available in PDF, EPUB and Kindle. Book excerpt: This thesis describes a search for singly produced top quarks via an electroweak vertex in head-on proton-antiproton collisions at a center of mass energy of √s = 1.96 TeV. The analysis uses a total of 2.3 fb−1 of data collected with the D0 detector at Fermilab, corresponding to two different run periods of the Tevatron collider. Two channels contribute to single top quark production at the Tevatron, the s-channel and the t-channel. In the s-channel, a virtual W boson is produced from the aniquilation of a quark and an antiquark and a top and a bottom quarks are produced from the W decay. The top quark decays almost exclusively into a W boson and a bottom quark. Final states are considered in which the W boson decays leptonically into an electron or a muon plus a neutrino. Thus, at the detector level, the final state characterizing the s-channel contains one lepton, missing energy accounting for the neutrino, and two jets from the two bottom quarks. In the t-channel, the final state has an additional jet coming from a light quark. Clearly, a precise reconstruction of the events requires a precise measurement of the energy of the jets. A multivariate technique, Bayesian neural networks, is used to extract the single top signal from the overwhelming background still left after event selection. A Bayesian likelihood probability is then computed to measure the single top cross section. Assuming the observed excess is due to single top events, the measured single top quark production cross section is [sigma](p{bar p} → tb + X, tqb + X) = 4.70{sub -0.93}{sup +1.18} pb. The observed excess is associated with a p-value of (3.2 ± 2.3) x 10−8, assuming the background-only hypothesis. This p-value corresponds to an excess over background of 5.4 standard deviations for a Gaussian density. The p-value computed using the standard model signal cross section of 3.46 pb is (22.7 ± 0.6) x 10−6, corresponding to an expected significance of 4.08 standard deviations.
Book Synopsis Measurement of the Single Top Quark Production Cross Section in 1.96-TeV Proton-Antiproton Collisions by :
Download or read book Measurement of the Single Top Quark Production Cross Section in 1.96-TeV Proton-Antiproton Collisions written by and published by . This book was released on 2009 with total page 157 pages. Available in PDF, EPUB and Kindle. Book excerpt: Top quarks are predominantly produced in pairs via the strong interaction in {bar p}p collisions at √s = 1.96 TeV . The top quark has a weak isospin 1/2, composing a weak isospin doublet with the bottom quark. This characteristic predicts not only top quark pair production via strong interaction but also single production together with a bottom quark via weak interaction. However, finding single top quark production is challenging since it is rarely produced ([sigma]{sub singletop} = 2.9 pb) against background processes with the same final state like W+jets and t{bar t}. A measurement of electroweak single top production probes the W-t-b vertex, which provides a direct determination of the Cabbibo-Kobayashi-Maskawa (CKM) matrix element.
Book Synopsis Measurement of the Single Top Quark Cross Section in the Lepton Plus Jets Final State in Proton-Antiproton Collisions at a Center of Mass Energy of 1.96 TeV Using the CDF II Detector by :
Download or read book Measurement of the Single Top Quark Cross Section in the Lepton Plus Jets Final State in Proton-Antiproton Collisions at a Center of Mass Energy of 1.96 TeV Using the CDF II Detector written by and published by . This book was released on 2012 with total page 222 pages. Available in PDF, EPUB and Kindle. Book excerpt: We present a measurement of the single top quark cross section in the lepton plus jets final state using an integrated luminosity corresponding to 7.5 fb-1 of p\bar p collision data collected by the Collider Detector at Fermilab. The single top candidate events are identified by the signature of a charged lepton, large missing transverse energy, and two or three jets with at least one of them identified as originating from a bottom quark. A new Monte Carlo generator POWHEG is used to model the single top quark production processes, which include s-channel, t-channel, and Wt-channel. A neural network multivariate method is exploited to discriminate the single top quark signal from the comparatively large backgrounds. We measure a single top production cross section of $3.04^{+0.57}_{-0.53} (\mathrm{stat.~+~syst.})$ pb assuming $m_{\rm top}=172.5$~GeV/$c^2$. In addition, we extract the CKM matrix element value $
Book Synopsis Measurement of the Single Top Quark Production Cross Section and [math Display by :
Download or read book Measurement of the Single Top Quark Production Cross Section and [math Display written by and published by . This book was released on 2014 with total page pages. Available in PDF, EPUB and Kindle. Book excerpt:
Book Synopsis Measurement of the Top Quark Production Cross Section in Proton-antiproton Collisions at 1.8 TeV Center of Mass Energy by : Peter Dominic Tamburello
Download or read book Measurement of the Top Quark Production Cross Section in Proton-antiproton Collisions at 1.8 TeV Center of Mass Energy written by Peter Dominic Tamburello and published by . This book was released on 1998 with total page 256 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Author :Anna Christine Henrichs Publisher :Springer Science & Business Media ISBN 13 :3319014870 Total Pages :231 pages Book Rating :4.3/5 (19 download)
Book Synopsis Top Quark Pair Production by : Anna Christine Henrichs
Download or read book Top Quark Pair Production written by Anna Christine Henrichs and published by Springer Science & Business Media. This book was released on 2013-10-04 with total page 231 pages. Available in PDF, EPUB and Kindle. Book excerpt: Before any kind of new physics discovery could be made at the LHC, a precise understanding and measurement of the Standard Model of particle physics' processes was necessary. The book provides an introduction to top quark production in the context of the Standard Model and presents two such precise measurements of the production of top quark pairs in proton-proton collisions at a center-of-mass energy of 7 TeV that were observed with the ATLAS Experiment at the LHC. The presented measurements focus on events with one charged lepton, missing transverse energy and jets. Using novel and advanced analysis techniques as well as a good understanding of the detector, they constitute the most precise measurements of the quantity at that time.
Book Synopsis Measurement of the Single Top Quark Production Cross Section and by :
Download or read book Measurement of the Single Top Quark Production Cross Section and written by and published by . This book was released on 2016 with total page pages. Available in PDF, EPUB and Kindle. Book excerpt: An updated measurement of the single top quark production cross section is presented using the full data set collected by the Collider Detector at Fermilab (CDF), corresponding to 9.5 fb-1 of integrated luminosity from proton-antiproton collisions at 1.96 TeV center-of-mass energy. The events selected contain an imbalance in the total transverse momentum, jets identified as containing b quarks, and no identified leptons. The sum of the s- and t-channel single top quark cross sections is measured to be 3.53-1.16+1.25 pb and a lower limit on the magnitude of the top-to-bottom quark coupling,
Book Synopsis Measurement of Electroweak Single Top Quark Production in Proton-antiproton Collisions at 1.96 TeV. by :
Download or read book Measurement of Electroweak Single Top Quark Production in Proton-antiproton Collisions at 1.96 TeV. written by and published by . This book was released on 2008 with total page 235 pages. Available in PDF, EPUB and Kindle. Book excerpt: The top quark is an extremely massive fundamental particle that is predominantly produced in pairs at particle collider experiments. The Standard Model of particle physics predicts that top quarks can also be produced singly by the electroweak force; however, this process is more difficult to detect because it occurs at a smaller rate and is more difficult to distinguish from background processes. The cross section of this process is related to the Cabbibo-Kobayashi-Maskawa matrix element.
Book Synopsis Measurement of the T-channel Single-top-quark Production Cross Section and of the by :
Download or read book Measurement of the T-channel Single-top-quark Production Cross Section and of the written by and published by . This book was released on 2014 with total page 43 pages. Available in PDF, EPUB and Kindle. Book excerpt: Measurements are presented of the t-channel single-top-quark production cross section in proton-proton collisions at √s = 8 TeV. The results are based on a data sample corresponding to an integrated luminosity of 19.7 fb−1 recorded with the CMS detector at the LHC. The cross section is measured inclusively, as well as separately for top (t) and antitop $ \left(\overline{\mathrm{t}}\right) $, in final states with a muon or an electron. The measured inclusive t-channel cross section is?t-ch. = 83.6 ± 2.3 (stat.) ± 7.4 (syst.) pb. The single t and $ \overline{\mathrm{t}} $ cross sections are measured to be?t-ch.(t) = 53.8 ± 1.5 (stat.) ± 4.4 (syst.) pb and?$_{t-ch.}$ $ \left(\overline{t}\right) $ = 27.6 ± 1.3 (stat.) ± 3.7 (syst.) pb, respectively. The measured ratio of cross sections is Rt-ch. =?t-ch.(t)/?t-ch. $ \left(\overline{\mathrm{t}}\right) $ = 1.95 ± 0.10 (stat.) ± 0.19 (syst.), in agreement with the standard model prediction. The modulus of the Cabibbo-Kobayashi-Maskawa matrix element Vtb is extracted and, in combination with a previous CMS result at √s = 7 TeV, a value.
Book Synopsis Top-Quark Pair Production Cross Sections and Calibration of the Top-Quark Monte-Carlo Mass by : Jan Kieseler
Download or read book Top-Quark Pair Production Cross Sections and Calibration of the Top-Quark Monte-Carlo Mass written by Jan Kieseler and published by Springer. This book was released on 2016-06-15 with total page 172 pages. Available in PDF, EPUB and Kindle. Book excerpt: This thesis presents the first experimental calibration of the top-quark Monte-Carlo mass. It also provides the top-quark mass-independent and most precise top-quark pair production cross-section measurement to date. The most precise measurements of the top-quark mass obtain the top-quark mass parameter (Monte-Carlo mass) used in simulations, which are partially based on heuristic models. Its interpretation in terms of mass parameters used in theoretical calculations, e.g. a running or a pole mass, has been a long-standing open problem with far-reaching implications beyond particle physics, even affecting conclusions on the stability of the vacuum state of our universe. In this thesis, this problem is solved experimentally in three steps using data obtained with the compact muon solenoid (CMS) detector. The most precise top-quark pair production cross-section measurements to date are performed. The Monte-Carlo mass is determined and a new method for extracting the top-quark mass from theoretical calculations is presented. Lastly, the top-quark production cross-sections are obtained – for the first time – without residual dependence on the top-quark mass, are interpreted using theoretical calculations to determine the top-quark running- and pole mass with unprecedented precision, and are fully consistently compared with the simultaneously obtained top-quark Monte-Carlo mass.
Book Synopsis Measurement of the Top Quark Pair Production Cross-section in Dimuon Final States in Proton-antiproton Collisions at 1.96 TeV by : Jens-Peter Konrath
Download or read book Measurement of the Top Quark Pair Production Cross-section in Dimuon Final States in Proton-antiproton Collisions at 1.96 TeV written by Jens-Peter Konrath and published by . This book was released on 2008 with total page pages. Available in PDF, EPUB and Kindle. Book excerpt:
Book Synopsis Measurement of Electroweak Single Top Quark Production in Proton-antiproton Collisions at 1.96 TeV by : Peter Joseph Dong
Download or read book Measurement of Electroweak Single Top Quark Production in Proton-antiproton Collisions at 1.96 TeV written by Peter Joseph Dong and published by . This book was released on 2008 with total page 424 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Book Synopsis Measurement of the Top Quark Pair Production Cross Section in Proton-antiproton Collisions at a Center of Mass Energy of 1.96 TeV, Hadronic Top Decays with the D0 Detector by :
Download or read book Measurement of the Top Quark Pair Production Cross Section in Proton-antiproton Collisions at a Center of Mass Energy of 1.96 TeV, Hadronic Top Decays with the D0 Detector written by and published by . This book was released on 2009 with total page 193 pages. Available in PDF, EPUB and Kindle. Book excerpt: Of the six quarks in the standard model the top quark is by far the heaviest: 35 times more massive than its partner the bottom quark and more than 130 times heavier than the average of the other five quarks. Its correspondingly small decay width means it tends to decay before forming a bound state. Of all quarks, therefore, the top is the least affected by quark confinement, behaving almost as a free quark. Its large mass also makes the top quark a key player in the realm of the postulated Higgs boson, whose coupling strengths to particles are proportional to their masses. Precision measurements of particle masses for e.g. the top quark and the W boson can hereby provide indirect constraints on the Higgs boson mass. Since in the standard model top quarks couple almost exclusively to bottom quarks (t 2!Wb), top quark decays provide a window on the standard model through the direct measurement of the Cabibbo-Kobayashi-Maskawa quark mixing matrix element V{sub tb}. In the same way any lack of top quark decays into W bosons could imply the existence of decay channels beyond the standard model, for example charged Higgs bosons as expected in two-doublet Higgs models: t 2!Hb. Within the standard model top quark decays can be classified by the (lepton or quark) W boson decay products. Depending on the decay of each of the W bosons, t{bar t} pair decays can involve either no leptons at all, or one or two isolated leptons from direct W 2!e{bar {nu}}{sub e} and W 2![mu]{bar {nu}}{sub {mu}} decays. Cascade decays like b 2!Wc 2!e{bar {nu}}{sub e}c can lead to additional non-isolated leptons. The fully hadronic decay channel, in which both Ws decay into a quark-antiquark pair, has the largest branching fraction of all t{bar t} decay channels and is the only kinematically complete (i.e. neutrino-less) channel. It lacks, however, the clear isolated lepton signature and is therefore hard to distinguish from the multi-jet QCD background. It is important to measure the cross section (or branching fraction) in each channel independently to fully verify the standard model. Top quark pair production proceeds through the strong interaction, placing the scene for top quark physics at hadron colliders. This adds an additional challenge: the huge background from multi-jet QCD processes. At the Tevatron, for example, t{bar t} production is completely hidden in light q{bar q} pair production. The light (i.e. not bottom or top) quark pair production cross section is six orders of magnitude larger than that for t{bar t} production. Even including the full signature of hadronic t{bar t} decays, two b-jets and four additional jets, the QCD cross section for processes with similar signature is more than five times larger than for t{bar t} production. The presence of isolated leptons in the (semi)leptonic t{bar t} decay channels provides a clear characteristic to distinguish the t{bar t} signal from QCD background but introduces a multitude of W- and Z-related backgrounds.
Book Synopsis Cross Section Measurement of T-channel Single Top Quark Production in Pp Collisions at $\sqrt{s} by :
Download or read book Cross Section Measurement of T-channel Single Top Quark Production in Pp Collisions at $\sqrt{s} written by and published by . This book was released on 2016 with total page pages. Available in PDF, EPUB and Kindle. Book excerpt: The cross section for the production of single top quarks in the $t$ channel is measured in proton-proton collisions at 13 TeV with the CMS detector at the LHC. The analyzed data correspond to an integrated luminosity of 2.3 fb$^{-1}$. The event selection requires one muon and two jets where one of the jets is identified as originating from a bottom quark. Several kinematic variables are then combined into a multivariate discriminator to distinguish signal from background events. A fit to the distribution of the discriminating variable yields a total cross section of 232 $\pm$ 13 (stat) $\pm$ 28 (syst) pb and a ratio of top quark and top antiquark production of $R_{t\textrm{-ch.}}= $ 1.81 $\pm$ 0.18 (stat) $\pm$ 0.15 (syst). From the total cross section the absolute value of the CKM matrix element $V_{\mathrm{tb}}$ is calculated to be 1.03 $\pm$ 0.07 (exp) $\pm$ 0.02 (theo). All results are in agreement with the standard model predictions.
Book Synopsis Measurement of the Single Top Quark and Antiquark Production Cross Sections in the T Channel and Their Ratio in Proton-proton Collisions at √s by : Albert M. Sirunyan
Download or read book Measurement of the Single Top Quark and Antiquark Production Cross Sections in the T Channel and Their Ratio in Proton-proton Collisions at √s written by Albert M. Sirunyan and published by . This book was released on 2018 with total page pages. Available in PDF, EPUB and Kindle. Book excerpt:
Book Synopsis Observation of S-channel Production of Single Top Quarks at the Tevatron by :
Download or read book Observation of S-channel Production of Single Top Quarks at the Tevatron written by and published by . This book was released on 2014 with total page pages. Available in PDF, EPUB and Kindle. Book excerpt: We report the first observation of single-top-quark production in the s channel through the combination of the CDF and D0 measurements of the cross section in proton-antiproton collisions at a center-of-mass energy of 1.96 TeV. The data correspond to total integrated luminosities of up to 9.7 fb-1 per experiment. The measured cross section is $\sigma_s = 1.29^{+0.26}_{-0.24}$ pb. The probability of observing a statistical fluctuation of the background to a cross section of the observed size or larger is $1.8 \times 10^{-10}$, corresponding to a significance of 6.3 standard deviations for the presence of an s-channel contribution to the production of single-top quarks.
Book Synopsis Measurement of Top Quark Pair Production Cross Section in Proton Antiproton Collisions at [square Root]s by : Sohrab Hossain
Download or read book Measurement of Top Quark Pair Production Cross Section in Proton Antiproton Collisions at [square Root]s written by Sohrab Hossain and published by . This book was released on 2009 with total page 278 pages. Available in PDF, EPUB and Kindle. Book excerpt:
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