QCD prediction for the non-$D\bar D$ annihilation decay of $\psi(3770)$

Understand

To clarify the marked difference between BES and CLEO measurements on the non-$D\bar D$ decays of the $\psi(3770)$, a $1^{3}D_{1}$-dominated charmonium, we calculate the annihilation decay of $\psi(3770)$ in NRQCD.

• By introducing the color-octet contributions, the results are free from infrared divergences.
• The color-octet matrix elements are estimated by solving the evolution equations.
• The S-D mixing effect is found to be very small.