The Standard Model of particle physics describes weak interactions mediated by massive gauge bosons that interact with each other in well-defined ways. Observations of the production and decay of WW, WZ, and ZZ boson pairs are an opportunity to check that these self-interactions agree with the Standard Model predictions. Furthermore, final states that include quarks are very similar to the most prominent final state of Higgs bosons produced in association with a W or Z boson. Diboson production where WW is a significant component has been observed at the Tevatron collider in semi-hadronic decay modes. We present a search for ZW and ZZ production in a final state containing two charged leptons and two jets using 8.9 fb−1 of data recorded with the CDF detector at the Tevatron. We select events by identifying those that contain two charged leptons, two hadronic jets, and low transverse missing energy ( E /T ). We increase our acceptance by using a wide suite of high- pT lepton triggers and by relaxing many lepton identification requirements. We develop a new method for calculating corrections to jet energies based on whether the originating parton was a quark or gluon to improve the agreement between data and the Monte Carlo simulations used to model our diboson signal and dominant backgrounds. We also make use of neural-network-based discriminants that are trained to pick out jets originating from b quarks and light-flavor quarks, thereby increasing our sensitivity to Z → bb ̄ and W/Z → qq ̄' decays, respectively. The number of signal events is extracted through a simultaneous fit to the dijet mass spectrum in three channels: a heavy-flavor tagged channel, a light-flavor tagged channel, and an untagged channel. We measure σZW/ZZ = 2.5+2.0-1.0 pb, which is consistent with the SM cross section of 5.1 pb. We establish an upper limit on the cross section of σZW/ZZ

We present a measurement of the production cross section for ZW and ZZ boson pairs in final states with a pair of charged leptons, from the decay of a Z boson, and at least two jets, from the decay of a W or Z boson, using the full sample of proton-antiproton collisions recorded with the CDF II detector at the Tevatron, corresponding to 8.9 fb(̂-1) of integrated luminosity. We increase the sensitivity to vector boson decays into pairs of quarks using a neural network discriminant that exploits the differences between the spatial spread of energy depositions and charged-particle momenta contained within the jet of particles originating from quarks and gluons. Additionally, we employ new jet energy corrections to Monte Carlo simulations that account for differences in the observed energy scales for quark and gluon jets. The number of signal events is extracted through a simultaneous fit to the dijet mass spectrum in three classes of events: events likely to contain jets with a heavy-quark decay, events likely to contain jets originating from light quarks, and events that fail these identification criteria. We determine the production cross section to be 2.5 +2.0 -1.0 pb (

In this thesis we present a search for the WZ and ZZ production in a final state ("W+2 jets") with a leptonically-decaying W and two energetic jets. We use the full dataset (+"Ldt = 8:9 fb-1) recorded with the CDF detector at Fermilab. The challenge consists in extracting the small Z-hadronic peak from the large amount of background processes. Those processes also include the WW, whose hadronic peak cannot be distinguished from the Z peak, due to the poor calorimeter resolution. In the past such a signature was used to measure the diboson cross section, which is highly dominated by the WW cross section.

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