# Exclusive double $B_c$ meson production from $e^+e^-$ annihilation into two virtual photons

## TL;DR

This paper calculates the production cross sections of $B_c$ meson pairs via two-photon mechanisms in electron-positron annihilation, considering relativistic effects and comparing with one-photon processes.

## Contribution

It introduces a relativistic quark model approach to compute $B_c$ meson pair production amplitudes and cross sections in electron-positron collisions.

## Key findings

- Relativistic corrections significantly affect cross section values.
- Two-photon production mechanism is quantitatively analyzed.
- Comparison shows differing contributions from one-photon and two-photon processes.

## Abstract

We calculate cross sections of a pair $B_c$ meson production on the basis of two-photon mechanism from electron-positron annihilation. We investigate the production cross sections in nonrelativistic approximation and with the account of relativistic corrections. Relativistic production amplitudes of S-wave pair pseudoscalar, vector and pseudoscalar+vector $B_c$-mesons are constructed on the basis of relativistic quark model. Numerical values of the production cross sections are obtained at different center-of-mass energies. The comparison of one-photon and two-photon annihilation contributions is presented.