Initial state radiation effects in inclusive $J/\psi$ production at B factories

Abstract

Based on Monte Carlo techniques, we analyze the initial state radiation (ISR) effects in prompt $\text{jpsi}$ inclusive production at B factories. ISR enhances cross section $\sigma (e^{-}{e}^{+}\to \text{jpsi}+gg+X)$ by about $15-25\%$, which is almost the same size as the QCD and relativistic correction. Moreover, ISR slightly changes $\sigma (e^{-}{e}^{+}\to \text{jpsi}+c\bar{c}+X)$. The $\text{jpsi}$ momentum spectrum in $e^{-}{e}^{+}\to \text{jpsi}+gg+X$ and in $e^{-}{e}^{+}\to \text{jpsi}+c\bar{c}+X$ is softer after the photon showering from the initial $e^{\pm }$ beam radiation. After combining the QCD,relativistic, and ISR corrections,a more precise theoretical result is obtained. The new result provides a more stringent constraint of the color-octet contribution to $\sigma (e^{-}{e}^{+}\to \text{jpsi}+X_{\mathrm{non}-\mathrm{c}\bar{\mathrm{c}}})$.

Comments: journal version;16 pages, 9 figures, 4 tables