Higgs boson decays to $B_c$ meson in the fragmentation-function approach

TL;DR

This paper calculates Higgs boson decay widths to various $B_c$ mesons using a high-order QCD fragmentation-function approach, providing precise predictions for future collider experiments.

Contribution

It introduces a higher-order QCD fragmentation-function calculation for Higgs decays to $B_c$ mesons, including resummation of large logarithms and comparison with nonrelativistic QCD results.

Findings

Decay widths are significantly reduced when including higher-order QCD corrections.

Approximately 120,000 $B_c$ events at HL-LHC and 1.6 million at HE-LHC are expected from Higgs decays.

The approach improves the precision of $B_c$ production predictions in Higgs decays.

Abstract

In the paper, we present a calculation of the decay widths for the Higgs boson decays to the $B_c$, $B_c^*$, $B_c(2^1S_0)$ and $B_c^*(2^3S_1)$ mesons using the fragmentation-function approach. In the calculation, the fragmentation functions up to order $\alpha_s^3$ based on the nonrelativistic QCD factorization theory are used, and the decay widths for $H\to Q+X$ and $H \to g+X$ at the partonic level are calculated up to order $\alpha_s$. The large logarithms of $m_H^2/m_{Bc}^2$ are resummed up to next-to-leading logarithmic accuracy by solving the evolution equations for the running quark masses and the fragmentation functions. Compared to the leading-order decay widths based on the nonrelativistic QCD approach, the decay widths based on the fragmentation-function approach that include the higher-order QCD corrections are reduced significantly. Our numerical results show that there are about $1.2\times 10^5$ $B_c$ events via the Higgs decays to be produced at the HL-LHC with $3ab^{-1}$, and about $1.6\times 10^6$ $B_c$ events via the Higgs decays to be produced at the HE-LHC with $15ab^{-1}$.