Photoproduction of the $B_c$ meson at the future $e^+e^-$ colliders

TL;DR

This paper investigates the production of various $B_c$ meson states through photoproduction mechanisms at future $e^+e^-$ colliders, highlighting the significance of resolved photon contributions and the observability of these mesons.

Contribution

It provides a detailed calculation of $B_c$ meson photoproduction, including both direct and resolved photon processes, within the non-relativistic QCD framework, for the first time at future colliders.

Findings

Resolved photoproduction contributions are significant and sometimes dominant.

$B_c$ mesons are promisingly observable at future high-energy colliders.

The study covers multiple $B_c$ states and photon sources.

Abstract

In the present paper, we study the photoproduction of various $S$-wave $B_c$ states, i.e. $B_c(1{}^1S_0)$, $B_c^*(1{}^1S_0)$, $B_c(2{}^1S_0)$ and $B^*_c(2{}^3S_1)$, at future $e^+e^-$ colliders within the framework of non-relativistic QCD. Two sources of the initial photons can be realized in the production, i.e., the LBS photon and the WWA photon. In addition to the direct photoproduction via the sub-process, $\gamma + \gamma \rightarrow B_c + b + \bar{c}$, we also calculate the resolved photoproduction via the sub-processes, $\gamma + g \rightarrow B_c + b + \bar{c}$ and $q + \bar{q} \rightarrow B_c + b + \bar{c}$ with $q=u,d,s,g$, respectively. Numerical results indicate that the contributions from the single resolved photoproduction are significant and even dominant at certain collision configuration. At the future high-energy and high-luminosity $e^+e^-$ colliders, the $B_c$ meson generated via the photoproduction mechanism is promisingly observable and can be well studied.