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The Charm Content of W+1 Jet Events as a Probe of the Strange Quark Distribution Function

U. Baur, F. Halzen, S. Keller, M. L. Mangano, K. Riesselmann

TL;DR

The paper examines whether associated W+c production at the Tevatron can constrain the proton's strange quark distribution by exploiting sg→Wc signals against backgrounds. It introduces cross-section ratios to reduce systematics, uses PYTHIA for parton-level simulations, and analyzes the sensitivity of the signal to different strange-quark PDFs (CTEQ1M vs MRSD0). The authors propose charm-tagging strategies and estimate luminosity requirements, concluding that ≈30 pb^-1 with ~10% charm tagging could start constraining the strange distribution, with stronger statements possible at higher luminosities. The work highlights practical paths and uncertainties for turning W+c measurements into a probe of flavor structure in the proton.

Abstract

We investigate the prospects for measuring the strange quark distribution function of the proton in associated $W$ plus charm quark production at the Tevatron. The $W+c$ quark signal produced by strange quark -- gluon fusion, $sg\rightarrow W^-c$ and $\bar sg\rightarrow W^+\bar c$, is approximately 5\% of the inclusive $W+1$ jet cross section for jets with a transverse momentum $p_T(j)>10$~GeV. We study the sensitivity of the $W$ plus charm quark cross section to the parametrization of the strange quark distribution function, and evaluate the various background processes. Strategies to identify charm quarks in CDF and DØ\ are discussed. For a charm tagging efficiency of about 10\% and an integrated luminosity of 30~pb$^{-1}$ or more, it should be possible to constrain the strange quark distribution function from $W+c$ production at the Tevatron.

The Charm Content of W+1 Jet Events as a Probe of the Strange Quark Distribution Function

TL;DR

The paper examines whether associated W+c production at the Tevatron can constrain the proton's strange quark distribution by exploiting sg→Wc signals against backgrounds. It introduces cross-section ratios to reduce systematics, uses PYTHIA for parton-level simulations, and analyzes the sensitivity of the signal to different strange-quark PDFs (CTEQ1M vs MRSD0). The authors propose charm-tagging strategies and estimate luminosity requirements, concluding that ≈30 pb^-1 with ~10% charm tagging could start constraining the strange distribution, with stronger statements possible at higher luminosities. The work highlights practical paths and uncertainties for turning W+c measurements into a probe of flavor structure in the proton.

Abstract

We investigate the prospects for measuring the strange quark distribution function of the proton in associated plus charm quark production at the Tevatron. The quark signal produced by strange quark -- gluon fusion, and , is approximately 5\% of the inclusive jet cross section for jets with a transverse momentum ~GeV. We study the sensitivity of the plus charm quark cross section to the parametrization of the strange quark distribution function, and evaluate the various background processes. Strategies to identify charm quarks in CDF and DØ\ are discussed. For a charm tagging efficiency of about 10\% and an integrated luminosity of 30~pb or more, it should be possible to constrain the strange quark distribution function from production at the Tevatron.

Paper Structure

This paper contains 5 sections, 6 equations, 4 figures, 2 tables.

Table of Contents

  1. Introduction
  2. Signal and Background
  3. Charm Quark Tagging in Tevatron Experiments
  4. Conclusions
  5. Acknowledgements

Figures (4)

  • Figure 1: Ratio of the strange quark distribution functions as a function of $x$ for the CTEQ1M and MRSD0 sets and two different values of $Q^2$.
  • Figure 2: The differential cross section $d\sigma/dx_s$ for the process $sg\rightarrow Wc$ at the Tevatron, using the CTEQ1M set. The cuts imposed are listed in Eq. 8.
  • Figure 3: The differential cross section ratios $R_1(p_T)$, $R_2(p_T)$, and $R_3(p_T)$ as a function of the jet $p_T$ for the MRSD0 and CTEQ1M sets at the Tevatron. The cuts imposed are listed in Eq. 8.
  • Figure 4: The transverse momentum distribution of the charm quark inside the jet for the signal, and the three background processes combined, at the Tevatron, using the CTEQ1M set. The cuts imposed are listed in Eq. 8.