Measurement of the Z[gamma] Production Cross Section in Pp Collisions at 8 TeV and Search for Anomalous Triple Gauge Boson Couplings

Measurement of the Z[gamma] Production Cross Section in Pp Collisions at 8 TeV and Search for Anomalous Triple Gauge Boson Couplings PDF Author:
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ISBN:
Category :
Languages : en
Pages : 40

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Book Description
The cross section for the production of Z[gamma] in proton-proton collisions at 8 TeV is measured based on data collected by the CMS experiment at the LHC corresponding to an integrated luminosity of 19.5 fb−1. Events with an oppositely-charged pair of muons or electrons together with an isolated photon are selected. The differential cross section as a function of the photon transverse momentum is measured inclusively and exclusively, where the exclusive selection applies a veto on central jets. The observed cross sections are compatible with the expectations of next-to-next-to-leading-order quantum chromodynamics. Limits on anomalous triple gauge couplings of ZZ[gamma] and Z[gamma][gamma] are set that improve on previous experimental results obtained with the charged lepton decay modes of the Z boson.

Measurement of the Z[gamma] Production Cross Section in Pp Collisions at 8 TeV and Search for Anomalous Triple Gauge Boson Couplings

Measurement of the Z[gamma] Production Cross Section in Pp Collisions at 8 TeV and Search for Anomalous Triple Gauge Boson Couplings PDF Author:
Publisher:
ISBN:
Category :
Languages : en
Pages : 40

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Book Description
The cross section for the production of Z[gamma] in proton-proton collisions at 8 TeV is measured based on data collected by the CMS experiment at the LHC corresponding to an integrated luminosity of 19.5 fb−1. Events with an oppositely-charged pair of muons or electrons together with an isolated photon are selected. The differential cross section as a function of the photon transverse momentum is measured inclusively and exclusively, where the exclusive selection applies a veto on central jets. The observed cross sections are compatible with the expectations of next-to-next-to-leading-order quantum chromodynamics. Limits on anomalous triple gauge couplings of ZZ[gamma] and Z[gamma][gamma] are set that improve on previous experimental results obtained with the charged lepton decay modes of the Z boson.

Measurement of the Z? Production Cross Section in Pp Collisions at 8 TeV and Search for Anomalous Triple Gauge Boson Couplings

Measurement of the Z? Production Cross Section in Pp Collisions at 8 TeV and Search for Anomalous Triple Gauge Boson Couplings PDF Author:
Publisher:
ISBN:
Category :
Languages : en
Pages : 40

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Book Description
The cross section for the production of Z? in proton-proton collisions at 8 TeV is measured based on data collected by the CMS experiment at the LHC corresponding to an integrated luminosity of 19.5 fb-1. Events with an oppositely-charged pair of muons or electrons together with an isolated photon are selected. Furthermore, the differential cross section as a function of the photon transverse momentum is measured inclusively and exclusively, where the exclusive selection applies a veto on central jets. These observed cross sections are compatible with the expectations of next-to-next-to-leading-order quantum chromodynamics. As a result, limits on anomalous triple gauge couplings of ZZ? and Z?? are set that improve on previous experimental results obtained with the charged lepton decay modes of the Z boson.

Measurements of Z? and Z?? Production in Pp Collisions at S

Measurements of Z? and Z?? Production in Pp Collisions at S PDF Author:
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Category :
Languages : en
Pages :

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Book Description
The production of Z bosons with one or two isolated high-energy photons is studied using pp collisions at √s=8 TeV. The analyses use a data sample with an integrated luminosity of 20.3 fb-1 collected by the ATLAS detector during the 2012 LHC data taking. The Z? and Z?? production cross sections are measured with leptonic (e+e-, ?+?-, ?????????) decays of the Z boson, in extended fiducial regions defined in terms of the lepton and photon acceptance. They are then compared to cross-section predictions from the Standard Model, where the sources of the photons are radiation off initial-state quarks and radiative Z-boson decay to charged leptons, and from fragmentation of final-state quarks and gluons into photons. The yields of events with photon transverse energy ET > 250 GeV from l+l-? events and with ET > 400 GeV from ?????????? events are used to search for anomalous triple gauge-boson couplings ZZ? and Z??. The yields of events with diphoton invariant mass m?? > 200 GeV from l+l-?? events and with m?? > 300 GeV from ??????????? events are used to search for anomalous quartic gauge-boson couplings ZZ?? and Z???. As a result, no deviations from Standard Model predictions are observed and limits are placed on parameters used to describe anomalous triple and quartic gauge-boson couplings.

Measurements of W±Z Production Cross Sections in Pp Collisions at S

Measurements of W±Z Production Cross Sections in Pp Collisions at S PDF Author:
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Category :
Languages : en
Pages :

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Book Description
This study presents measurements of W±Z production in pp collisions at a center-of-mass energy of 8 TeV. The gauge bosons are reconstructed using their leptonic decay modes into electrons and muons. The data were collected in 2012 by the ATLAS experiment at the Large Hadron Collider and correspond to an integrated luminosity of 20.3 fb-1. The measured inclusive cross section in the detector fiducial region is ?W±Z→l'?ll = 35.1 ± 0.9(stat) ± 0.8(sys) ± 0.8(lumi) fb, for one leptonic decay channel. In comparison, the next-to-leading-order Standard Model expectation is 30.0 ± 2.1 fb. Cross sections for W+Z and W-Z production and their ratio are presented as well as differential cross sections for several kinematic observables. Limits on anomalous triple gauge boson couplings are derived from the transverse mass spectrum of the W±Z system. From the analysis of events with a W and a Z boson associated with two or more forward jets an upper limit at 95% confidence level on the W±Z scattering cross section of 0.63 fb, for each leptonic decay channel, is established, while the Standard Model prediction at next-to-leading order is 0.13 ± 0.01 fb. Limits on anomalous quartic gauge boson couplings are also extracted.

Evidence of W?? Production in Pp Collisions at S

Evidence of W?? Production in Pp Collisions at S PDF Author:
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Languages : en
Pages :

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Book Description
Here we report evidence of triple gauge boson production pp→W(l?)??+X, which is accessible for the first time with the 8 TeV LHC data set. The fiducial cross section for this process is measured in a data sample corresponding to an integrated luminosity of 20.3 fb−1, collected by the ATLAS detector in 2012. Events are selected using the W boson decay to e? or ?? as well as requiring two isolated photons. The measured cross section is used to set limits on anomalous quartic gauge couplings in the high diphoton mass region.

Measurement of the Pp {u2192} ZZ Production Cross Section and Constraints on Anomalous Triple Gauge Couplings in Four-lepton Final States at {u221A}s

Measurement of the Pp {u2192} ZZ Production Cross Section and Constraints on Anomalous Triple Gauge Couplings in Four-lepton Final States at {u221A}s PDF Author:
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ISBN:
Category :
Languages : en
Pages : 23

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Book Description
A measurement of the inclusive ZZ production cross section and constraints on anomalous triple gauge couplings in proton–proton collisions at √s = 8 TeV are presented. The analysis is based on a data sample, corresponding to an integrated luminosity of 19.6 fb−1, collected with the CMS experiment at the LHC. The measurements are performed in the leptonic decay modes ZZ → lll'l', where l = e,? and l' = e,?,?. The measured total cross section ?(pp → ZZ) = 7.7 ± 0.5 (stat)-0.4+0.5 (syst) ± 0.4 (theo) ± 0.2 (lumi) pb, for both Z bosons produced in the mass range 60 msubZ/sub 120 GeV, is consistent with standard model predictions. Differential cross sections are measured and well described by the theoretical predictions. As a result, the invariant mass distribution of the four-lepton system is used to set limits on anomalous ZZZ and ZZ? couplings at the 95% confidence level: –0.004 fsub4/subsupZ/sup 0.004, –0.004 fsub5/subsupZ/sup 0.004, –0.005 fsub4

Measurement of the Pp 2!ZZ Production Cross Section and Constraints on Anomalous Triple Gauge Couplings in Four-lepton Final States at [arrow]"

Measurement of the Pp 2!ZZ Production Cross Section and Constraints on Anomalous Triple Gauge Couplings in Four-lepton Final States at [arrow] Author:
Publisher:
ISBN:
Category :
Languages : en
Pages : 23

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Book Description
A measurement of the inclusive ZZ production cross section and constraints on anomalous triple gauge couplings in proton-proton collisions at [arrow]" = 8 TeV are presented. The analysis is based on a data sample, corresponding to an integrated luminosity of 19.6 fb−1, collected with the CMS experiment at the LHC. The measurements are performed in the leptonic decay modes ZZ 2!lll'l', where l = e, [mu] and l' = e, [mu], [tau]. The measured total cross section [sigma](pp 2!ZZ) = 7.7 " 0.5 (stat)-0.4+0.5 (syst) " 0.4 (theo) " 0.2 (lumi) pb, for both Z bosons produced in the mass range 60

A Measurement of W Boson Pair Production in Pp Collisions at Sqrt(s)

A Measurement of W Boson Pair Production in Pp Collisions at Sqrt(s) PDF Author: Philip Sommer
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Languages : en
Pages :

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Book Description
Zusammenfassung: In this thesis, measurements of the W boson pair production cross section in proton-proton collisions at a centre-of-mass energy of 8 TeV are presented. A dataset corresponding to an integrated luminosity of 22.3 /fb recorded by the ATLAS experiment in the year 2012 is used. The W bosons are identified by their decay products of exactly two leptons with opposite electrical charge, electrons or muons, and missing transverse momentum induced by their corresponding neutrinos. First, a measurement restricted to final states without hadronic jets is presented and differential fiducial cross sections, total cross sections and limits on anomalous triple gauge boson couplings are obtained. A second measurement of the fiducial cross section in association with exactly one hadronic jet is presented. The ratio of fiducial cross sections for different jet multiplicities is reported and the combined fiducial cross section is extrapolated to the total phase space.

A Measurement of the Z Gamma Cross Section and Limits on Anomalous Triple Gauge Couplings at Square Root of S

A Measurement of the Z Gamma Cross Section and Limits on Anomalous Triple Gauge Couplings at Square Root of S PDF Author:
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ISBN:
Category :
Languages : en
Pages : 328

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Book Description
A study of the properties of the Z$\gamma$ diboson system is presented using 5.0 fb$^{-1}$ of proton-proton collision data from the LHC using the CMS detector. The pp $\rightarrow Z(\rightarrow\mu \mu) \gamma$ and pp $\rightarrow Z(\rightarrow e e) \gamma$ production cross sections are measured within the fiducial volume of CMS with a combined measurement of $\sigma_{\ell\ell\gamma} = 5.33 \pm 0.08 ~\text{(stat.)} \pm 0.25 ~\text{(syst.)} \pm 0.12 ~\text{(lumi.)}$ pb that is in good agreement with Standard Model predictions. Upper limits on the neutral anomalous triple gauge couplings set are the most stringent limits on these couplings to date, with allowed regions: $-0.010

Measurements of the $ZZ$ Production Cross Sections in the $2\ell2\nu$ Channel in Proton-proton Collisions at $\sqrt{s}$

Measurements of the $ZZ$ Production Cross Sections in the $2\ell2\nu$ Channel in Proton-proton Collisions at $\sqrt{s}$ PDF Author:
Publisher:
ISBN:
Category :
Languages : en
Pages : 33

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Book Description
Measurements of the ZZ production cross sections in proton-proton collisions at center-of-mass energies of 7 and 8 TeV are presented. We found that candidate events for the leptonic decay mode ZZ 2!2l2[nu], where l denotes an electron or a muon, are reconstructed and selected from data corresponding to an integrated luminosity of 5.1 (19.6)fb-1 at 7 (8) TeV collected with the CMS experiment. The measured cross sections, [sigma](pp 2!ZZ)=5.1+1.5-1.4(stat)+1.4-1.1(syst)"0.1(lumi)pb at 7 TeV, and 7.2+0.8-0.8(stat)+1.9-1.5(syst)"0.2(lumi)pb at 8 TeV, are in good agreement with the standard model predictions with next-to-leading-order accuracy. Furthermore, the selected data are analyzed to search for anomalous triple gauge couplings involving the ZZ final state. In the absence of any deviation from the standard model predictions, limits are set on the relevant parameters. As a result, these limits are then combined with the previously published CMS results for ZZ in 4l final states, yielding the most stringent constraints on the anomalous couplings.