Observation of WZ Production


The large W and Z boson production cross sections in pp􏰇 collisions at the Fermilab Tevatron have been measured with high precision. The production of heavy vector boson pairs (WW , WZ, and ZZ) is far less common and can involve the triple gauge couplings (TGCs) between the bosons themselves via an intermediate virtual boson. Deviations of measured diboson production properties from standard model (SM) predictions could arise from new interactions or loop effects due to new particles at energy scales not directly accessible to a given experiment.

On the CDF experiment, I lead an analysis that made the first observation of WZ production. This result was published in . We used the full-leptonic decay of both bosons to observe WZ production, which was also the first trilepton signal to be observed. Some kinematic distributions are shown below:

The signal significance was 6σ. Having established a WZ signal, we measured the production cross section to be

σ (ppbar –> WZ) = 5.01.8-1.4 (stat.) ± 0.4 (syst.) pb

Using similar analysis techniques on the CDF experiment, we also made the first measurement of ZZ production at a hadron collider PRL 100 (2008) 201801.

I have also authored two review articles on tests of electroweak physics RMP 84 (2012) 1477 and diboson physics at colliders ARNPS 61 (2011) 223.

Further Reading

  1. A. Abulencia et al. [CDF Collaboration], “Observation of WZ Production”, Phys. Rev. Lett. 98, 161801 (2007).

  2. T. Aaltonen et al. [CDF Collaboration], “First Measurement of ZZ Production in ppbar Collisions at ps = 1.96 TeV”, Phys. Rev. Lett. 100, 201801 (2008)

  3. Neubauer, Mark S. “Diboson production at colliders”, Ann. Rev. Nucl. Part. Sci. 61, 223–250 (2011).

  4. Hobbs, John D. and Neubauer, Mark S. and Willenbrock, Scott, “Tests of the Standard Electroweak Model at the Energy Frontier”, Rev. Mod. Phys. 84, 1477 (2012)