Top-Charm Associated Production at High Energy e^+e^- Colliders in Standard Model

TL;DR

This paper calculates the extremely rare flavor-changing neutral current process for top-charm production at high-energy electron-positron colliders within the Standard Model, revealing cross sections much smaller than previous estimates.

Contribution

It provides precise calculations of the top-charm production cross section considering all quark masses, showing significantly lower rates than earlier predictions.

Findings

Cross section at 200 GeV: 1.84 x 10^{-9} fb

Cross section at 500 GeV: 0.572 x 10^{-9} fb

Result is 10^{-5} times smaller than previous estimates.

Abstract

The flavor changing neutral current tcV (V=\gamma,Z) couplings in the production vertex for the process $e^+e^-\to t\bar c$ or $\bar t c$ in the standard model are investigated. The precise calculations keeping all quark masses non-zero are carried out. The total production cross section is found to be $1.84 \times 10^{-9}$ fb at $\sqrt s =200 GeV$ and $0.572 \times 10^{-9}$ fb at $\sqrt s =500 GeV$ respectively. The result is much smaller than that given in ref. \cite{clwy} by a factor of $10^{-5}$.