› › Z Gamma Cross Section Measurement Sigma*br Z Gamma In The Electron Channel For Pbarp Collisions At Sqrts




Measurement of W-gamma and Z-gamma Production in Pp Collisions at Sqrt(s)

Author :

Publisher :

Page : 32 pages

File Size : 10,87 MB

Release : 2011

Category :

ISBN :

Get eBook

Book Description

A measurement of W-gamma and Z-gamma production in proton-proton collisions at sqrt(s) = 7 TeV is presented. Results are based on a data sample recorded by the CMS experiment at the LHC, corresponding to an integrated luminosity of 36 inverse picobarns. The electron and muon decay channels of the W and Z are used. The total cross sections are measured for photon transverse energy>10 GeV and spatial separation from charged leptons in the plane of pseudorapidity and azimuthal angle>0.7, and with an additional dilepton invariant mass requirement of> 50 GeV for the Z-gamma process. The following cross section times branching fraction values are found: sigma(pp to W-gamma+X) B(W to lepton neutrino) = 56.3 +/- 5.0 (stat.) +/- 5.0 (syst.) +/- 2.3 (lumi.) pb and sigma(pp to Z-gamma+X) B}(Z to lepton lepton) = 9.4 +/- 1.0 (stat.) +/- 0.6 (syst.) +/- 0.4 (lumi.) pb. These measurements are in agreement with standard model predictions. The first limits on anomalous WW gamma, ZZ gamma, and Z gamma gamma trilinear gauge couplings at sqrt(s) = 7 TeV are set.



Z +? Cross-section Measurement,?*BR(Z +?), in the Electron Channel for P{bar P} Collisions at √s

Author :

Publisher :

Page : 109 pages

File Size : 21,89 MB

Release : 1994

Category :

ISBN :

Get eBook

Book Description

The Z +? cross-section x branching ratio in the electron channel has been measured using the inclusive Z data sample from the CDF 1988--1989 collider run, for which the total integrated luminosity was 4.05 ± 0.28 pb−1. Two Z? candidates are observed from central photon events with?R/{sub?}> 0.7 and E{sub t}{sup?}> 5.0 GeV. From these events the? * BR(Z +?) is measured and compared with SM predictions:? * BR(Z +?){sub e} = 6.8{sub -5.7}{sup +5.7}(stat + syst)pb? * BR(Z + {gamma})SM = 4.7{sub -4.7}{sup +0.7}(stat + syst)pb. From this ZZ{sub {gamma}} cross section measurement limits on the Z{sub {gamma}{gamma}} and couplings for three different choices of compositeness scale?{sub Z} are obtained. The experimental sensitivity to the h30{sup Z, {gamma}}/h10{sup Z, {gamma}} couplings is in the range of?{sub Z} - 450--500 GeV and for the h40{sup Z{gamma}}/h20{sup Z, {gamma}} couplings?{sub Z} - 300 GeV.





Measurement of the $ \mathrm{ Z } \gamma \rightarrow \nu \bar{\nu} \gamma$ Production Cross Section in Pp Collisions at $\sqrt{s}

Author :

Publisher :

Page : pages

File Size : 37,5 MB

Release : 2016

Category :

ISBN :

Get eBook

Book Description

A measurement of the Z gamma to nu nu-bar gamma production cross section in pp collisions at sqrt(s) = 8 TeV is presented, using data corresponding to an integrated luminosity of 19.6 inverse-femtobarns collected with the CMS detector at the LHC. This measurement is based on the observation of events with large missing energy and with a single photon with transverse momentum above 145 GeV and absolute pseudorapidity in the range



Measurement of Z Gamma Production in Pbar{p} Collisions at Sqrt{s}

Author :

Publisher :

Page : 8 pages

File Size : 29,88 MB

Release : 2010

Category :

ISBN :

Get eBook

Book Description

The production rate and kinematics of photons produced in association with Z bosons are studied using 2 fb−1 of p{bar p} collision data collected at the Collider Detector at Fermilab. The cross section for p{bar p} → ll−? + X (where the leptons l are either muons or electrons with dilepton mass M{sub l{ell}}> 40 GeV/c2, and where the photon has transverse energy E{sub T}{sup?}> 7 GeV and is well separated from the leptons) is 4.6 ± 0.2 (stat) ± 0.3 (syst) ± 0.3 (lum) pb, which is consistent with standard model expectations. We use the photon ET distribution from Z{gamma} events where the Z has decayed to?+?−, e+e−, or?{bar {nu}} to set limits on anomalous (non-standard-model) trilinear couplings between photons and Z bosons.



Measurement of the Inclusive W and Z Production Cross Sections in Pp Collisions at $ \sqrt {s}

Author :

Publisher :

Page : pages

File Size : 48,33 MB

Release : 2011

Category :

ISBN :

Get eBook

Book Description

A measurement of inclusive W and Z production cross sections in pp collisions at sqrt(s)=7 TeV is presented. The electron and muon decay channels are analyzed in a data sample collected with the CMS detector at the LHC and corresponding to an integrated luminosity of 36 inverse picobarns. The measured inclusive cross sections are sigma(pp-> WX) B(W-> l nu) = 10.30 +/- 0.02 (stat.) +/- 0.10 (syst.) +/- 0.10 (th.) +/- 0.41 (lumi.) nb and sigma(pp -> ZX) B(Z-> l+̂l-̂) = 0.974 +/- 0.007 (stat.) +/- 0.007 (syst.) +/- 0.018 (th.) +/- 0.039 (lumi.) nb, limited to the dilepton invariant mass range 60 to 120 GeV. The luminosity-independent cross section ratios are [sigma(pp->WX) B(W-> l nu)]/[sigma(pp-> ZX) B(Z->l+̂l-̂)] = 10.54 +/- 0.07 (stat.) +/- 0.08 (syst.) +/- 0.16 (th.) and [sigma(pp->W+̂X) B(W+̂ -> l+̂nu)] / [sigma(pp->W-̂ X) B(W-̂ -> l-̂ nu)] = 1.421 +/- 0.006 (stat.) +/- 0.014 (syst.) +/- 0.029 (th.). The measured values agree with next-to-next-to-leading order QCD cross section calculations based on recent parton distribution functions.