Measurement of the T-channel Single-top-quark Production Cross Section and of the

Measurement of the T-channel Single-top-quark Production Cross Section and of the
Author:
Publisher:
Total Pages: 43
Release: 2014
Genre:
ISBN:

Download Measurement of the T-channel Single-top-quark Production Cross Section and of the Book in PDF, Epub and Kindle

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.

Spin Correlations in tt Events from pp Collisions

Spin Correlations in tt Events from pp Collisions
Author: Boris Lemmer
Publisher: Springer
Total Pages: 246
Release: 2015-06-24
Genre: Science
ISBN: 3319189328

Download Spin Correlations in tt Events from pp Collisions Book in PDF, Epub and Kindle

This thesis introduces readers to the Standard Model, the top quark and its properties, before explaining the concept of spin correlation measurement. The first measurement of top quark spin correlations at the LHC in the lepton+jets decay channel is presented. As the heaviest elementary particle, the top quark plays an essential role in the Standard Model of elementary particle physics. In the case of top quarks being produced in pairs at hadron colliders, the Standard Model predicts their spins to be correlated. The degree of correlation depends on both the production mechanism and properties of the top quark. Any deviation from the Standard Model prediction can be an indicator for new physics phenomena. The thesis employs an advanced top quark reconstruction algorithm including dedicated identification of the up- and down-type quarks from the W boson decay.

Particle Physics At The Silver Jubilee Of Lomonosov Conferences - Proceedings Of The Eighteenth Lomonosov Conference On Elementary Particle Physics

Particle Physics At The Silver Jubilee Of Lomonosov Conferences - Proceedings Of The Eighteenth Lomonosov Conference On Elementary Particle Physics
Author: Studenikin Alexander I
Publisher: World Scientific
Total Pages: 612
Release: 2019-05-28
Genre: Science
ISBN: 9811202346

Download Particle Physics At The Silver Jubilee Of Lomonosov Conferences - Proceedings Of The Eighteenth Lomonosov Conference On Elementary Particle Physics Book in PDF, Epub and Kindle

The volume of these proceedings is devoted to a wide variety of items, both in theory and experiment, of particle physics such as neutrino and astroparticle physics, tests of standard model and beyond, hadron physics, gravitation and cosmology, physics at the present and future accelerators.

Cross Section Measurement of T-channel Single Top Quark Production in Pp Collisions at $\sqrt{s}

Cross Section Measurement of T-channel Single Top Quark Production in Pp Collisions at $\sqrt{s}
Author:
Publisher:
Total Pages:
Release: 2016
Genre:
ISBN:

Download Cross Section Measurement of T-channel Single Top Quark Production in Pp Collisions at $\sqrt{s} Book in PDF, Epub and Kindle

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.

Top Quark Physics at Hadron Colliders

Top Quark Physics at Hadron Colliders
Author: Arnulf Quadt
Publisher: Springer Science & Business Media
Total Pages: 166
Release: 2007-08-16
Genre: Science
ISBN: 3540710604

Download Top Quark Physics at Hadron Colliders Book in PDF, Epub and Kindle

This will be a required acquisition text for academic libraries. More than ten years after its discovery, still relatively little is known about the top quark, the heaviest known elementary particle. This extensive survey summarizes and reviews top-quark physics based on the precision measurements at the Fermilab Tevatron Collider, as well as examining in detail the sensitivity of these experiments to new physics. Finally, the author provides an overview of top quark physics at the Large Hadron Collider.

Measurement of the Single Top Quark Production Cross Section and

Measurement of the Single Top Quark Production Cross Section and
Author:
Publisher:
Total Pages:
Release: 2016
Genre:
ISBN:

Download Measurement of the Single Top Quark Production Cross Section and Book in PDF, Epub and Kindle

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,

Measurement of the Top Quark Mass Using Single Top Quark Events in Proton-proton Collisions at $\sqrt{s}$

Measurement of the Top Quark Mass Using Single Top Quark Events in Proton-proton Collisions at $\sqrt{s}$
Author:
Publisher:
Total Pages:
Release: 2017
Genre:
ISBN:

Download Measurement of the Top Quark Mass Using Single Top Quark Events in Proton-proton Collisions at $\sqrt{s}$ Book in PDF, Epub and Kindle

A measurement of the top quark mass is reported in events containing a single top quark produced via the electroweak t channel. The analysis is performed using data from proton-proton collisions collected with the CMS detector at the LHC at a centre-of-mass energy of 8 TeV, corresponding to an integrated luminosity of 19.7 inverse femtobarns. The top quark is reconstructed from its decay to a W boson and a b quark, with the W boson decaying leptonically to a muon and a neutrino. The specific topology and kinematic properties of single top quark events in the t channel are used to enhance the purity of the sample, suppressing the contribution from top quark pair production. A fit to the invariant mass distribution of reconstructed top quark candidates yields a value of the top quark mass of 172.95 +/- 0.77 (stat) +0.97/-0.93 (syst) GeV. This result is in agreement with the current world average, and represents the first measurement of the top quark mass in event topologies not dominated by top quark pair production.

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

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
Author:
Publisher:
Total Pages: 222
Release: 2012
Genre:
ISBN:

Download 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 Book in PDF, Epub and Kindle

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 $