Measurement of the TtZ Production Cross Section in the Final State with Three Charged Leptons Using 36.1 Fb^-1 of Pp Collisions at 13 TeV at the ATLAS Detector

Measurement of the TtZ Production Cross Section in the Final State with Three Charged Leptons Using 36.1 Fb^-1 of Pp Collisions at 13 TeV at the ATLAS Detector PDF Author: Nils-Arne Rosien
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Languages : en
Pages : 0

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Book Description
A measurement of the production cross section for a top quark pair in association with a Z boson (ttZ) is presented in this PhD thesis. Final states with exactly three charged leptons (electrons or muons) are used, taking into account the decay of the top quark pair in the lepton+jets channel and the decay of the Z boson into two charged leptons. The dataset used for this analysis corresponds to 36.1 fb^-1 of proton-proton collisions at a centre-of-mass energy of 13 TeV, recorded during 2015 and 2016 by the ATLAS detector at the Large Hadron Collider. The result of a profile likelihood fit ...

Measurement of the TtZ Production Cross Section in the Final State with Three Charged Leptons Using 36.1 Fb^-1 of Pp Collisions at 13 TeV at the ATLAS Detector

Measurement of the TtZ Production Cross Section in the Final State with Three Charged Leptons Using 36.1 Fb^-1 of Pp Collisions at 13 TeV at the ATLAS Detector PDF Author: Nils-Arne Rosien
Publisher:
ISBN:
Category :
Languages : en
Pages : 0

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Book Description
A measurement of the production cross section for a top quark pair in association with a Z boson (ttZ) is presented in this PhD thesis. Final states with exactly three charged leptons (electrons or muons) are used, taking into account the decay of the top quark pair in the lepton+jets channel and the decay of the Z boson into two charged leptons. The dataset used for this analysis corresponds to 36.1 fb^-1 of proton-proton collisions at a centre-of-mass energy of 13 TeV, recorded during 2015 and 2016 by the ATLAS detector at the Large Hadron Collider. The result of a profile likelihood fit ...

Measurement of the $t\bar{t}$ Production Cross Section Using Events with One Lepton and at Least One Jet in Pp Collisions at $\sqrt{s}$

Measurement of the $t\bar{t}$ Production Cross Section Using Events with One Lepton and at Least One Jet in Pp Collisions at $\sqrt{s}$ PDF Author:
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Languages : en
Pages :

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Book Description
A measurement of the $\mathrm{ t \bar{t} }$ production cross section at $\sqrt{s}=$ 13 TeV is presented using proton-proton collisions, corresponding to an integrated luminosity of 2.3 fb$^{-1}$, collected with the CMS detector at the LHC. Final states with one isolated charged lepton (electron or muon) and at least one jet are selected and categorized according to the accompanying jet multiplicity. From a likelihood fit to the invariant mass distribution of the isolated lepton and a jet identified as coming from the hadronization of a bottom quark, the cross section is measured to be $\sigma(\mathrm{ t \bar{t} })=$ 835 $\pm$ 3 (stat) $\pm$ 23 (syst) $\pm$ 23 (lumi) pb, in agreement with the standard model prediction. Using the expected dependence of the cross section on the pole mass of the top quark ($m_{\mathrm{ t }}$), the value of $m_{\mathrm{ t }}$ is found to be 172.7$^{+2.4}_{-2.7}$ GeV.

Simultaneous Measurements of the Tt{u00AF} , W+W- , and Z/?*{u2192}?? Production Cross-sections in Pp Collisions at S

Simultaneous Measurements of the Tt{u00AF} , W+W- , and Z/?*{u2192}?? Production Cross-sections in Pp Collisions at S PDF Author:
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Languages : en
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Book Description
Simultaneous measurements of the tt¯, W+W–, and Z/?*→?? production cross-sections using an integrated luminosity of 4.6 fb–1 of pp collisions at √s=7 TeV collected by the ATLAS detector at the LHC are presented. Events are selected with two high transverse momentum leptons consisting of an oppositely charged electron and muon pair. The three processes are separated using the distributions of the missing transverse momentum of events with zero and greater than zero jet multiplicities. Measurements of the fiducial cross-section are presented along with results that quantify for the first time the underlying correlations in the predicted and measured cross-sections due to proton parton distribution functions. Results indicate that the correlated next-to-leading-order predictions for tt¯ and Z/?*→?? underestimate the data, while those at next-to-next-to-leading-order generally describe the data well. The full cross-sections are measured to be ?(tt¯)=181.2 ± 2.8+9.7–9.5 ± 3.3 ± 3.3 pb, ?(W+W–) = 53.3 ± 2.7+7.3–8.0 ± 1.0 ± 0.5 pb, and ?(Z/?*→??) = 1174 ± 24+72–87 ± 21 ± 9 pb, where the cited uncertainties are due to statistics, systematic effects, luminosity and the LHC beam energy measurement, respectively. The W+W– measurement includes the small contribution from Higgs boson decays, H → W+W–.

Measurement of the Top Pair Production Cross Section in 8 TeV Proton-proton Collisions Using Kinematic Information in the Lepton + Jets Final State with ATLAS.

Measurement of the Top Pair Production Cross Section in 8 TeV Proton-proton Collisions Using Kinematic Information in the Lepton + Jets Final State with ATLAS. PDF Author:
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Languages : en
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Measurement of the $W+̂W-̂$ Cross Section in Pp Collisions at $\sqrt{s}$

Measurement of the $W+̂W-̂$ Cross Section in Pp Collisions at $\sqrt{s}$ PDF Author:
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ISBN:
Category :
Languages : en
Pages : 29

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Book Description
A measurement of the W boson pair production cross section in proton-proton collisions at √ s = 8 TeV is presented. The data we collected with the CMS detector at the LHC correspond to an integrated luminosity of 19.4 fb-1 . The W+W- candidates are selected from events with two charged leptons, electrons or muons, and large missing transverse energy. The measured W+W- cross section is 60.1 ± 0.9 (stat) ± 3.2 (exp) ± 3.1 (theo) ± 1.6 (lumi) pb = 60.1 ± 4.8 pb, consistent with the standard model prediction. The W+W-cross sections are also measured in two different fiducial phase space regions. In addition, the normalized differential cross section is measured as a function of kinematic variables of the final-state charged leptons and compared with several perturbative QCD predictions. Limits on anomalous gauge couplings associated with dimension-six operators are also given in the framework of an effective field theory. Finally, the corresponding 95% confidence level intervals are -5.7 csubWWW/sub/?sup2/sup 5.9 TeVsup-2/sup, -11.4 csubW/sub/?sup2/sup 5.4 TeVsup-2/sup , -29.2 csubB

Measurement of the WZ Production Cross Section in Pp Collisions at $\sqrt{s}$

Measurement of the WZ Production Cross Section in Pp Collisions at $\sqrt{s}$ PDF Author:
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Languages : en
Pages :

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Book Description
The WZ production cross section is measured by the CMS experiment at the CERN LHC in proton-proton collision data samples corresponding to integrated luminosities of 4.9 fb$^{-1}$ collected at $ \sqrt{s} = $ 7 TeV, and 19.6 fb$^{-1}$ at $ \sqrt{s} = $ 8 TeV. The measurements are performed using the fully-leptonic WZ decay modes with electrons and muons in the final state. The measured cross sections for 71 $

Measurement of the ZZ Production Cross Section and Z {u2192} L+l{u2013}l'+l'{u2013} Branching Fraction in Pp Collisions at

Measurement of the ZZ Production Cross Section and Z {u2192} L+l{u2013}l'+l'{u2013} Branching Fraction in Pp Collisions at PDF Author:
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Category :
Languages : en
Pages : 24

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Book Description
Here, four-lepton production in proton–proton collisions, pp→(Z/?*)(Z/?*)→l+l–l'+l'–,where l,l'=e or ?, is studied at a center-of-mass energy of 13 TeV with the CMS detector at the LHC. The data sample corresponds to an integrated luminosity of 2.6 fb–1. The ZZ production cross section, ?(pp → ZZ)=14.6–1.8+1.9(stat)–0.3+0.5(syst)±0.2(theo)±0.4(lumi)pb, is measured for events with two opposite-sign, same-flavor lepton pairs produced in the mass region 60msublsup+/suplsup–/sup/sub,ml'sup+/supl'sup–/sup120 GeV60mlsup+/suplsup–/sup,ml'sup+/supl'sup–/sup120 GeV. The Z boson branching fraction to four leptons is measured to be B(Z→lsup+/suplsup–/supl'sup+/supl'sup–/sup)=4.9sub–0.7/subsup+0.8/sup (stat)sub–0.2/subsup+0.3/sup (syst)–0.1+0.2(theo)±0.1(lumi)×10sup–6/sup for the four-lepton invariant mass in the range 80mlsup+/suplsup–/supl'sup+/supl'sup–/sup100 GeV80mlsup+/suplsup–/supl'sup+/supl'sup–/sup

Measurements of ZZ Production Cross Section Using Four-lepton Events and Constraints on Anomalous Triple Gauge Couplings at [squareroot]s

Measurements of ZZ Production Cross Section Using Four-lepton Events and Constraints on Anomalous Triple Gauge Couplings at [squareroot]s PDF Author: Usama Hussain
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Category :
Languages : en
Pages : 219

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Book Description
Studies of four-lepton production in proton-proton collisions, pp → (Z/[gamma]*)(Z/[gamma]*)→ 4l, where l = e or [mu], using data collected during 2016-2018 (Run II) are presented. The dataset corresponds to an integrated luminosity of 137 fb^(−1) at a center-of-mass energy of 13 TeV, collected by the CMS detector at the LHC. All reported measurements use the 2l2l' final states, where l,l' = e or [mu]. The total ZZ cross section for all events with two Z bosons in the mass range 60-120 GeV is measured and found to be [sigma](pp → ZZ) = 17.2 ± 0.3 (stat) ± 0.5 (syst) ± 0.4 (theo) ± 0.3 (lumi) pb. Differentialcross sections are measured as functions of a number of kinematic observables. Allthese results agree with standard model predictions. Searches for anomalous triplegauge couplings are performed, and the four-lepton invariant mass distributions areused to set the most stringent limits to date on a number of parameters affectingneutral gauge boson interactionsl

Measurement of the $ZZ$ Production Cross Section in $pp$ Collisions at $\sqrt{s}$

Measurement of the $ZZ$ Production Cross Section in $pp$ Collisions at $\sqrt{s}$ PDF Author:
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Languages : en
Pages :

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Book Description
The ZZ production cross section in proton-proton collisions at 13 TeV center-of-mass energy is measured using 3.2 fb–1 of data recorded with the ATLAS detector at the Large Hadron Collider. The considered Z boson candidates decay to an electron or muon pair of mass 66–116 GeV. The cross section is measured in a fiducial phase space reflecting the detector acceptance. It is also extrapolated to a total phase space for Z bosons in the same mass range and of all decay modes, giving 16.7+2.2–2.0(stat)+0.9–0.7(syst)+1.0–0.7(lumi) pb. Lastly, the results agree with standard model predictions.

Measurement of the Ttbar Production Cross Section in the All-jets Final State in Pp Collisions at $\sqrt{s}$

Measurement of the Ttbar Production Cross Section in the All-jets Final State in Pp Collisions at $\sqrt{s}$ PDF Author:
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ISBN:
Category :
Languages : en
Pages : 34

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Book Description
The cross section for tt production in the all-jets final state is measured in pp collisions at a centre-of-mass energy of 8 TeV at the LHC with the CMS detector, in data corresponding to an integrated luminosity of 18.4 fb-1. The inclusive cross section is found to be 275.6 ±6.1 (stat) ± 37.8 (syst) ± 7.2 (lumi) pb. The normalized differential cross sections are measured as a function of the top quark transverse momenta, pT, and compared to predictions from quantum chromodynamics. The results are reported at detector, parton, and particle levels. In all cases, the measured top quark pT spectra are significantly softer than theoretical predictions.