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Measurement of the Inclusive Jet Cross Section in ${\bar p p}$ collisions at $\sqrt{s}=1.8$ TeV

T. Affolder

TL;DR

This work reports a precise measurement of the inclusive jet cross section in p-pbar collisions at sqrt(s)=1.8 TeV over a wide jet-E_T range, using the CDF detector and 87 pb^-1 of data. It implements a detailed unsmearing procedure that ties jet energy corrections to detector response, underlying-event modeling, and fragmentation, with a thorough accounting of experimental and theoretical uncertainties. By comparing smeared NLO QCD predictions with the data and employing a novel PDF-ranking approach, the study finds that PDFs with a large high-x gluon component (notably CTEQ4HJ) describe the data best, though other PDFs remain feasible within uncertainties. The results, consistent with Run 1A and D0, validate NLO QCD predictions across seven orders of magnitude in jet production rates when PDF flexibility is properly included, and provide a framework for discriminating PDFs via Δχ^2 analyses.

Abstract

We present results from the measurement of the inclusive jet cross section for jet transverse energies from 40 to 465 GeV in the pseudo-rapidity range $0.1<|η|<0.7$. The results are based on 87 $pb^{-1}$ of data collected by the CDF collaboration at the Fermilab Tevatron Collider. The data are consistent with previously published results. The data are also consistent with QCD predictions given the flexibility allowed from current knowledge of the proton parton distributions. We develop a new procedure for ranking the agreement of the parton distributions with data and find that the data are best described by QCD predictions using the parton distribution functions which have a large gluon contribution at high $E_T$ (CTEQ4HJ).

Measurement of the Inclusive Jet Cross Section in ${\bar p p}$ collisions at $\sqrt{s}=1.8$ TeV

TL;DR

This work reports a precise measurement of the inclusive jet cross section in p-pbar collisions at sqrt(s)=1.8 TeV over a wide jet-E_T range, using the CDF detector and 87 pb^-1 of data. It implements a detailed unsmearing procedure that ties jet energy corrections to detector response, underlying-event modeling, and fragmentation, with a thorough accounting of experimental and theoretical uncertainties. By comparing smeared NLO QCD predictions with the data and employing a novel PDF-ranking approach, the study finds that PDFs with a large high-x gluon component (notably CTEQ4HJ) describe the data best, though other PDFs remain feasible within uncertainties. The results, consistent with Run 1A and D0, validate NLO QCD predictions across seven orders of magnitude in jet production rates when PDF flexibility is properly included, and provide a framework for discriminating PDFs via Δχ^2 analyses.

Abstract

We present results from the measurement of the inclusive jet cross section for jet transverse energies from 40 to 465 GeV in the pseudo-rapidity range . The results are based on 87 of data collected by the CDF collaboration at the Fermilab Tevatron Collider. The data are consistent with previously published results. The data are also consistent with QCD predictions given the flexibility allowed from current knowledge of the proton parton distributions. We develop a new procedure for ranking the agreement of the parton distributions with data and find that the data are best described by QCD predictions using the parton distribution functions which have a large gluon contribution at high (CTEQ4HJ).

Paper Structure

This paper contains 45 sections, 24 equations, 46 figures, 20 tables.

Table of Contents

  1. Introduction
  2. Inclusive Jet Cross Sections
  3. Theoretical framework
  4. Measurements and predictions in the 1980's
  5. Jet measurements and predictions in the 1990's
  6. Parton clustering
  7. Choice of the $\mu$ scale
  8. Experimental measurements
  9. Summary
  10. The CDF Detector
  11. Data Set
  12. Trigger
  13. Z vertex and multiple interactions
  14. Jet clustering
  15. Trigger efficiency
  16. ...and 30 more sections

Figures (46)

  • Figure 1: Jet events in the CDF calorimeter. A jet clustering cone of radius 0.7 is shown around each jet. Clockwise from the upper left they are identified as two-jet, two-jet, five-jet and three-jet. Tracks for these events are shown in Figure \ref{['CDFCTC']}.
  • Figure 2: The same jet events in the CDF central tracking chamber. Clockwise from the upper left they are identified as two-jet, two-jet, five-jet and three-jet The calorimeter information for these events is shown in Figure \ref{['CDFLEGO']}.
  • Figure 3: Contributions of the various subprocesses to the inclusive jet cross section. This plot was generated with CTEQ4Mand $\mu=E_{T}/2$.
  • Figure 4: One quarter section of the CDF detector.
  • Figure 5: Minimum separation (in units of cluster radius) between the 3rd jet and the 1st or 2nd jet in different bins of jet $E_T$. At a separation of 1.3R at least 50% of the clusters are separated.
  • ...and 41 more figures