Measurement of the Top Quark Pole Mass and QCD Radiation in Tt̄ Pair Production Using Eμ Events with B-tagged Jets in Pp Collisions at √s

Measurement of the Top Quark Pole Mass and QCD Radiation in Tt̄ Pair Production Using Eμ Events with B-tagged Jets in Pp Collisions at √s PDF Author: Caroline Maria Bertsche
Publisher:
ISBN:
Category : Collisions (Nuclear physics)
Languages : en
Pages : 542

Get Book Here

Book Description

Measurement of the Top Quark Pole Mass and QCD Radiation in Tt̄ Pair Production Using Eμ Events with B-tagged Jets in Pp Collisions at √s

Measurement of the Top Quark Pole Mass and QCD Radiation in Tt̄ Pair Production Using Eμ Events with B-tagged Jets in Pp Collisions at √s PDF Author: Caroline Maria Bertsche
Publisher:
ISBN:
Category : Collisions (Nuclear physics)
Languages : en
Pages : 542

Get Book Here

Book Description


Measurement of the Top Quark Pair Production Cross Section and an In-situ B-tagging Efficiency Calibration with ATLAS in Proton-proton Collisions at Center of Mass Energy

Measurement of the Top Quark Pair Production Cross Section and an In-situ B-tagging Efficiency Calibration with ATLAS in Proton-proton Collisions at Center of Mass Energy PDF Author: Bin Guo
Publisher:
ISBN: 9780494782064
Category :
Languages : en
Pages : 234

Get Book Here

Book Description
We present a measurement of the top anti-top quark (tt ̄ ) production cross section in the dilepton final states from proton-proton collisions at a center of mass energy at 7 TeV at the LHC. A b-tagging algorithm based on tracks displaced from the event interaction vertex is applied to identify bottom quark jets from top quark decay and reject background events. Given the relatively pure sample of bottom quark jets in tt ̄ dilepton final states, a new technique to measure in-situ the b-tagging efficiency is introduced that uses the distribution of the number of observed b-tagged jets. We present results with data collected at the ATLAS detector in 2010 with an integrated luminosity of 35 pb -1. The measured tt ̄ cross section is 176+22-21stat. +20-20 (syst.) +/- 6 (lum.) pb in the dilepton channel. We will also discuss the future prospects of this measurement.

Measurement of the Top Quark Pair Production Cross Section and an In-situ B-tagging Efficiency Calibration with ATLAS in Pp Collisions at √s

Measurement of the Top Quark Pair Production Cross Section and an In-situ B-tagging Efficiency Calibration with ATLAS in Pp Collisions at √s PDF Author: Bin Guo
Publisher:
ISBN:
Category :
Languages : en
Pages :

Get Book Here

Book Description
We present a measurement of the top anti-top quark (ttbar)production cross section in the dilepton final states from proton-proton collisions at a center of mass energy at 7 TeV at the LHC. A b-tagging algorithm based on tracks displaced from the event interaction vertex is applied to identify bottom quark jets from top quark decay and reject background events. Given the relatively pure sample of bottom quark jets in ttbar dilepton final states, a new technique to measure in-situ the b-tagging efficiency is introduced that uses the distribution of the number of observed b-tagged jets. We present results with data collected at the ATLAS detector in 2010 with an integrated luminosity of 35 pb-1. The measured ttbar cross section is 176 +22/-21 (stat.) ± 20 (syst.) ± 6 (lum.) pb in the dilepton channel. We will also discuss the future prospects of this measurement.

Measurement of Jets Produced in Top Quark Events Using the Emu Final State with 2 B-tagged Jets in Pp Collisions at 8 TeV with the ATLAS Detector

Measurement of Jets Produced in Top Quark Events Using the Emu Final State with 2 B-tagged Jets in Pp Collisions at 8 TeV with the ATLAS Detector PDF Author: Jacquelyn Kay Brosamer
Publisher:
ISBN:
Category :
Languages : en
Pages : 198

Get Book Here

Book Description
The transverse momentum and multiplicity of jets produced in top quark events are measured using 20.3 inverse fb of pp collision data at a center-of-mass energy of 8 tev. Jets are selected from top events requiring an opposite-charge $e\mu$ pair and two b-tagged jets in the final state. The data are corrected to obtain the particle-level fiducial cross section for additional jets with rank 1-4, where rank=1 is the leading additional jet. These distributions are used to obtain the extra jet multiplicity as a function of minimum jet pt threshold. The results are compared with several next to leading order Monte Carlo generators. The resulting measurements can be used to tune Monte Carlo QCD modelling and may also reduce associated modelling uncertainties for LHC top quark physics measurements.

Determination of the Top-quark Pole Mass and Strong Coupling Constant from the T T-bar Production Cross Section in Pp Collisions at $\sqrt{s}$

Determination of the Top-quark Pole Mass and Strong Coupling Constant from the T T-bar Production Cross Section in Pp Collisions at $\sqrt{s}$ PDF Author:
Publisher:
ISBN:
Category :
Languages : en
Pages : 22

Get Book Here

Book Description
The inclusive cross section for top-quark pair production measured by the CMS experiment in proton-proton collisions at a center-of-mass energy of 7 TeV is compared to the QCD prediction at next-to-next-to-leading order with various parton distribution functions to determine the top-quark pole mass, $m_t^{pole}$, or the strong coupling constant, $\alpha_S$. With the parton distribution function set NNPDF2.3, a pole mass of 176.7$^{+3.0}_{-2.8}$ GeV is obtained when constraining $\alpha_S$ at the scale of the Z boson mass, $m_Z$, to the current world average. Alternatively, by constraining $m_t^{pole}$ to the latest average from direct mass measurements, a value of $\alpha_S(m_Z)$ = 0.1151$^{+0.0028}_{-0.0027}$ is extracted. This is the first determination of $\alpha_S$ using events from top-quark production.

Measurement of the Top Quark Pair Production Cross Section in Pp Collisions at a Center-of-mass Energy of 7 TeV with the CMS Experiment at the LHC

Measurement of the Top Quark Pair Production Cross Section in Pp Collisions at a Center-of-mass Energy of 7 TeV with the CMS Experiment at the LHC PDF Author: Geng-Yuan Jeng
Publisher:
ISBN:
Category : Large Hadron Collider (France and Switzerland)
Languages : en
Pages : 140

Get Book Here

Book Description
We perform a measurement of the top quark pair production cross section in pp collisions at a center-of-mass energy of 7 TeV at the Large Hadron Collider. The analysis is based on a 36 pb -1 dataset collected with the CMS experiment in 2010. We study the kinematic characteristics of events with exactly one isolated muon in association with additional hard jets and exhibiting substantial missing transverse energy to distinguish the tt− signal from the electroweak and QCD multijet backgrounds. The tt− signal is extracted by simultaneously fitting the tri-jet invariant mass distributions in events with exactly three jets and at least four jets. The measured cross section is 157 ± 12(stat.[Special characters omitted.] (syst.) ± 6(lumi.) pb, which is consistent with the theoretical predictions.

QCD Radiation in Top-Antitop and Z+Jets Final States

QCD Radiation in Top-Antitop and Z+Jets Final States PDF Author: Kiran Joshi
Publisher: Springer
ISBN: 3319196537
Category : Science
Languages : en
Pages : 188

Get Book Here

Book Description
This thesis contains new research in both experimental and theoretical particle physics, making important contributions in each. Two analyses of collision data from the ATLAS experiment at the LHC are presented, as well as two phenomenological studies of heavy coloured resonances that could be produced at the LHC. The first data analysis was the measurement of top quark-antiquark production with a veto on additional jet activity. As the first detector-corrected measurement of jet activity in top-antitop events it played an important role in constraining the theoretical modelling, and ultimately reduced these uncertainties for ATLAS's other top-quark measurements by a factor of two. The second data analysis was the measurement of Z+2jet production and the observation of the electroweak vector boson fusion (VBF) component. As the first observation of VBF at a hadron collider, this measurement demonstrated new techniques to reliably extract VBF processes and paved the way for future VBF Higgs measurements. The first phenomenological study developed a new technique for identifying the colour of heavy resonances produced in proton-proton collisions. As a by-product of this study an unexpected and previously unnoticed correlation was discovered between the probability of correctly identifying a high-energy top and the colour structure of the event it was produced in. The second phenomenological study explored this relationship in more detail, and could have important consequences for the identification of new particles that decay to top quarks.

Measurement of Jet Activity in Top Quark Events Using the E[mu] Final State with Two B-tagged Jets in Pp Collisions at $\sqrt{s}

Measurement of Jet Activity in Top Quark Events Using the E[mu] Final State with Two B-tagged Jets in Pp Collisions at $\sqrt{s} PDF Author:
Publisher:
ISBN:
Category :
Languages : en
Pages : 62

Get Book Here

Book Description


A Measurement of the Mass of the Top Quark in Lepton + Jets Events at CDF

A Measurement of the Mass of the Top Quark in Lepton + Jets Events at CDF PDF Author: Erik Matthews Brubaker
Publisher:
ISBN:
Category :
Languages : en
Pages : 236

Get Book Here

Book Description


Measurement of the Top-quark Mass in All-jets $t\bar{t}$ Events in Pp Collisions at $\sqrt{s}$

Measurement of the Top-quark Mass in All-jets $t\bar{t}$ Events in Pp Collisions at $\sqrt{s}$ PDF Author:
Publisher:
ISBN:
Category :
Languages : en
Pages : 33

Get Book Here

Book Description
The mass of the top quark is measured using a sample of $t\bar{t}$ candidate events with at least six jets in the final state. The sample is selected from data collected with the CMS detector in pp collisions at $\sqrt{s}$ = 7 TeV in 2011 and corresponds to an integrated luminosity of 3.54 inverse femtobarns. The mass is reconstructed for each event employing a kinematic fit of the jets to a $t\bar{t}$ hypothesis. The top-quark mass is measured to be 173.49 $\pm$ 0.69 (stat.) $\pm$ 1.21 (syst.) GeV. A combination with previously published measurements in other decay modes by CMS yields a mass of 173.54 $\pm$ 0.33 (stat.) $\pm$ 0.96 (syst.) GeV.