A Measurement Of The Zz L L Vv Cross Section At 8 Tev And Limits On Anomalous Neutral Triple Gauge Couplings With The Atlas Detector

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.

In this thesis, the first measurement of Z(vv̄)[photon] cross section in pp collisions at [square root of]s = 7 TeV has been done using data collected by the CMS detector. The measured cross section is 21.3 ± 4.2 (stat.) ± 4.3 (syst.) ± 0.5 (lumi.) fb. This measurement is based on the observations of events with missing transverse energy in excess of 130 GeV and photon in the rapidity range [eta]

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

This Letter describes the current most precise measurement of the WZ production cross section as well as limits on anomalous WWZ couplings at a center-of-mass energy of 1.96 TeV in proton-antiproton collisions. The WZ candidates are reconstructed from decays containing three charged leptons and missing energy from a neutrino, where the charged leptons are either electrons or muons. Using data collected by the CDF II detector (7.1 fb−1 of integrated luminosity), 64 candidate events are observed with the expected background contributing 8 ± 1 events. The measured total cross section?(p{bar p} → WZ) = 3.93{sub -0.53}{sup +0.60}(stat){sub -0.46}{sup +0.59}(syst) pb is in good agreement with the standard model prediction of 3.50 ± 0.21. The same sample is used to set limits on anomalous WWZ couplings.