Is the colour-octet mechanism consistent with the double $J/ψ$ production measurement at B-factories?

Abstract

Double $J/ψ$ production in $e^+e^-$ collisions involving colour-octet channels are evaluated up to order $α^2α_s^3$. Having implemented the variation of the parameters ($m_c$, $μ_r$ and long-distance matrix elements), we found that the cross sections for producing double $J/ψ$ at B-factories range from $-0.016$fb to $0.245$fb, which are even much smaller than that via the colour-siglet mechanism. Accordingly, this result is consistent with the measurement by the Belle and BABAR Collaborations.