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Higgs boson decay to massive bottom quarks at order $α_s^4$ induced by top-quark Yukawa couplings

Jian Wang, Xing Wang, Yefan Wang

Abstract

The Higgs boson decay to massive bottom quarks has the largest branching ratio. The decay is mainly induced by the bottom-quark Yukawa coupling with the decay rate calculated up to $\mathcal{O}(α_s^4)$ assuming the massless final-state bottom quark. The top-quark Yukawa coupling induced contribution starts at $\mathcal{O}(α_s^2)$, and exhibits logarithmic and power enhancements, making the perturbative expansion converge slowly. We present a calculation of such contributions at $\mathcal{O}(α_s^4)$ to the decay into massive bottom quarks in which the squared amplitudes contain two top-quark Yukawa couplings. We find that they increase the decay width, relative to the result up to $\mathcal{O}(α_s^3)$, by $0.4\%$, larger than the experimental precision at future lepton colliders, and reduce the scale dependence significantly down to $0.4\%$.

Higgs boson decay to massive bottom quarks at order $α_s^4$ induced by top-quark Yukawa couplings

Abstract

The Higgs boson decay to massive bottom quarks has the largest branching ratio. The decay is mainly induced by the bottom-quark Yukawa coupling with the decay rate calculated up to assuming the massless final-state bottom quark. The top-quark Yukawa coupling induced contribution starts at , and exhibits logarithmic and power enhancements, making the perturbative expansion converge slowly. We present a calculation of such contributions at to the decay into massive bottom quarks in which the squared amplitudes contain two top-quark Yukawa couplings. We find that they increase the decay width, relative to the result up to , by , larger than the experimental precision at future lepton colliders, and reduce the scale dependence significantly down to .
Paper Structure (6 sections, 32 equations, 44 figures, 1 table)

This paper contains 6 sections, 32 equations, 44 figures, 1 table.

Table of Contents

  1. Introduction
  2. Calculation framework
  3. Analytic calculation of MIs
  4. Numerical results
  5. Conclusion
  6. Topological diagrams of the master integrals

Figures (44)

  • Figure 2: The decay width of $H\to b\bar{b}$ in the $\overline{\rm MS}$ scheme at different perturbative orders. The error bar denotes the scale uncertainty.
  • Figure 3: The decay width of $H\to b\bar{b}$ as a function of the bottom quark mass $\overline{m_b}\,(m_H)$ that varies from 2.584 GeV to 2.984 GeV.
  • Figure : (a)
  • Figure : $\text{M}_{1}$
  • Figure : (a)
  • ...and 39 more figures