Search for W+/-Z0 Anomalous Triple Gauge Coupling Production in the ppbar Collisions at √s=1.96 TeV

• Authors: Shih-Chieh Hsu, Elliot Lipeles, Mark Neubauer, Matthew Norman, Rami Vanguri, Frank Wurthwein.
• Data: Run II, 1.9/fb

Contents

• Introduction
• Summary of Results
  • Med. Bin Results
  • High Bin Results;
  • Combined Fits
• Control Region

Introduction

We report a search for anomalous W^+/-Z⁰ production in the ppbar collisions at √s=1.96 TeV using the two charged lepton, two jet final state. The primary signature of anomalous production would lie in events produced at high Center-of-Mass energies, which we model through the transverse momentum of the dilepton.


t-channel

s-channel




Summary of Results

We present results in three bins in dilepton pT. The Control Region, from 105-140 GeV, the Medium or Med Region from 140-210 GeV, and the High region, above 210 GeV. For each region we report the expected yields of the SM channels from the CDF PYTHIA Monte Carlo, in contrast with the actual data values. Because we do not expect PYTHIA to accurately reflect the yields in the high pT tails of the Drell-Yan distribution, we use a floating fit to discriminate between signal and background. The results of the fit, in graphical and tabular form, are reported below.

Med Bin Results: 140-210 GeV Dilepton Pt

Signal and background expectations and observed events in the signal region from background and SM WZ. The values in the table represent background and Standard Model expectations from the CDF PYTHIA MC compared to data, and contain statistical errors only.

Dijet Mass plot for Medium Bin, showing MC expectations and data results.

Dilepton Mass plot for Medium Bin, showing MC expectations and data results.

High Bin Results: 210+ GeV Dilepton Pt

Background and SM WZ expectations and observed events in the High Bin; The values in the table represent background and Standard Model expectations from the CDF PYTHIA MC compared to data, and contain statistical errors only.

Dijet Mass plot for the High Bin, showing MC expectations and data results.

Dilepton Mass plot for the High Bin, showing MC expectations and data results.

Limits on aTGC parameters for a form factor of 1.5 TeV.

Limits on aTGC parameters for a form factor of 2.0 TeV.

Cross-section limits on WZ production in the appropriate bins.

Control Regions Overview

We use a single control region, binned from 140 GeV to 210 GeV in dilepton Pt, to validate the data modeling. This region is dominated in the extreme by high Pt Drell-Yan, making it ideal to examine background with high Pt distributions.

Results from the Control Region are displayed here: The values in the table represent background and Standard Model expectations from the CDF PYTHIA MC compared to data, and contain statistical errors only.

Dijet Mass plot for Bin 3, showing MC expectations and data results.

Dilepton Mass plot for the Control Region, showing MC expectations and data results.

Fit Overview

Our unbinned dijet mass fit returns a signal fraction that best fits the data we observed in our sample. Those signal fractions float completely and are allowed to negative. The results from the fit are displayed below.

The signal fractions for the various fits are displayed here:

Fit comparison for the Control Region.

Fit comparison for the Med Bin.

Fit comparison for the High Bin.

Matthew Norman