Search for WW and WZ production in lepton plus jets final state at CDF

TL;DR

This paper reports a search for WW and WZ diboson production in lepton plus jets final states at the Fermilab Tevatron, using neural networks to improve sensitivity and setting upper limits consistent with Standard Model predictions.

Contribution

It introduces a neural network-based method to enhance detection sensitivity for WW and WZ production in hadron collider data.

Findings

Set a 95% CL upper limit of 2.88 pb on combined WW and WZ production cross section.

Result is consistent with the Standard Model next-to-leading order prediction of 2.09 pb.

Developed an artificial neural network to improve signal discrimination.

Abstract

We present a search for WW and WZ production in final states that contain a charged lepton (electron or muon) and at least two jets, produced in sqrt(s) = 1.96 TeV ppbar collisions at the Fermilab Tevatron, using data corresponding to 1.2 fb-1 of integrated luminosity collected with the CDF II detector. Diboson production in this decay channel has yet to be observed at hadron colliders due to the large single W plus jets background. An artificial neural network has been developed to increase signal sensitivity, as compared with an event selection based on conventional cuts. We set a 95% confidence level upper limit of sigma_{WW}* BR(W->lnu,W->jets)+ sigma_{WZ}*BR(W->lnu,Z->jets) <2.88 pb, which is consistent with the standard model next to leading order cross section calculation for this decay channel of 2.09+-0.12 pb.