Abstract：A new observable, the angle between ${\it \Lambda}$ and $\bar{\it \Lambda}$ decay planes, is proposed to test the theoretical predictions on the spin correlation. With 10 billion $J/\psi$ events collected with the BESIII detector at the BEPCII $e^+e^-$ collider, the distribution of the angle could be measured to verify whether or not a correlation exists.
2019, Vol. 36 
