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Measuring the top-quark Yukawa coupling at hadron colliders via tth, h->WW

F. Maltoni, D. Rainwater, S. Willenbrock

TL;DR

The paper evaluates the feasibility of measuring the top-quark Yukawa coupling via tt̄h production with h→WW at the LHC and a future 100 TeV VLHC. By analyzing 2-, 3-, and 4-lepton final states and accounting for detector effects and backgrounds, it shows that the Yukawa coupling can be constrained with about 16%, 8%, and 12% statistical precision at the LHC for mh = 130, 160, 190 GeV, respectively, while at the VLHC the statistical uncertainty would be negligible and systematic uncertainties would dominate. A detailed treatment of backgrounds such as tt̄Wjj, tt̄ℓℓ, and tt̄tt̄ informs the prospects and underscores the importance of background estimation and potential jet-veto strategies. The study highlights the complementary role of other channels (e.g., tt̄h, h→ZZ) and the need for precise background modeling to achieve a robust top Yukawa measurement at hadron colliders.

Abstract

We study the signal and background for the process tth, h->WW at the LHC and a 100 TeV VLHC. Signals are studied in two-, three-, and four-lepton final states. We find a statistical uncertainty in the top-quark Yukawa coupling at the LHC of 16%, 8%, 12% for m_h = 130, 160, 190 GeV, respectively. The statistical uncertainty at the VLHC is likely to be negligible in comparison with the systematic uncertainty.

Measuring the top-quark Yukawa coupling at hadron colliders via tth, h->WW

TL;DR

The paper evaluates the feasibility of measuring the top-quark Yukawa coupling via tt̄h production with h→WW at the LHC and a future 100 TeV VLHC. By analyzing 2-, 3-, and 4-lepton final states and accounting for detector effects and backgrounds, it shows that the Yukawa coupling can be constrained with about 16%, 8%, and 12% statistical precision at the LHC for mh = 130, 160, 190 GeV, respectively, while at the VLHC the statistical uncertainty would be negligible and systematic uncertainties would dominate. A detailed treatment of backgrounds such as tt̄Wjj, tt̄ℓℓ, and tt̄tt̄ informs the prospects and underscores the importance of background estimation and potential jet-veto strategies. The study highlights the complementary role of other channels (e.g., tt̄h, h→ZZ) and the need for precise background modeling to achieve a robust top Yukawa measurement at hadron colliders.

Abstract

We study the signal and background for the process tth, h->WW at the LHC and a 100 TeV VLHC. Signals are studied in two-, three-, and four-lepton final states. We find a statistical uncertainty in the top-quark Yukawa coupling at the LHC of 16%, 8%, 12% for m_h = 130, 160, 190 GeV, respectively. The statistical uncertainty at the VLHC is likely to be negligible in comparison with the systematic uncertainty.

Paper Structure

This paper contains 8 sections, 3 figures, 5 tables.

Table of Contents

  1. Introduction
  2. Signal and backgrounds
  3. $\ell^\pm\ell^\pm$
  4. $3\ell$
  5. $4\ell$
  6. Calculations
  7. Results
  8. Conclusions

Figures (3)

  • Figure 1: A representative Feynman diagram for associated production of the Higgs boson and a $t\bar{t}$ pair, followed by the decay $h\to W^+W^-$.
  • Figure 2: The statistical uncertainty in the top-quark Yukawa coupling, $\delta y_t/y_t$, from $t\bar{t}h$, $h\to W^+W^-$ at the low-luminosity LHC (30 fb$^{-1}$ of integrated luminosity). Results for the two- and three-lepton final states, as well as their sum, are shown.
  • Figure 3: Same as Fig. \ref{['fig:precisionlow']}, but at the high-luminosity LHC (300 fb$^{-1}$ of integrated luminosity).