Year: 2026
Type: preprint
Abstract: We study $B_c^{(*)}$ production in $Z$-boson decays at next-to-leading order (NLO) in QCD within the color-singlet nonrelativistic QCD framework. The analysis covers both the $1S$ and $2S$ pseudoscalar and vector states, extending the phenomenological study to radially excited $B_c$ mesons. We calculate direct production widths and energy-fraction and invariant-mass distributions, including both charm- and bottom-quark production topologies. For the central inputs and $μ_R=2m_b$, the $K$ factors are $1.52$ for $B_c$ and $1.33$ for $B_c^*$. We examine uncertainties from the renormalization scale, heavy-quark masses, and wave functions at the origin, and apply the principle of maximum conformality to fix the renormalization scale from the $β_0$-dependent NLO contribution. The NLO corrections enhance the small- and intermediate-energy-fraction regions and modify the invariant-mass spectra. We discuss these features in relation to heavy-quark fragmentation. The results provide production-rate and kinematic inputs for studies of ground-state and radially excited $B_c$ mesons at high-statistics $Z$ factories.
Source: arXiv (Cornell University)
Authors: Ke, Qi-Wei, Guo, Lei, Zeng, Jun, Zheng, Xu-Chang
Institutions: Chongqing University, Hainan Normal University
Language: English
Subfield: Nuclear and High Energy Physics
Field: Physics and Astronomy
Domain: Physical Sciences
Open Access status: green
Awards: G2515165303, G3604773249, G4243555374
OpenAlex ID: W7222510870