https://indico.ihep.ac.cn//event/8183/

First,Gushan introducedmproved measurements of 𝜒𝑐𝐽→𝛴+𝛴-−and 𝛴0𝛴0 decays.Next,Gushan answered some questions.

Yuhang:In TABLE II,the theoretical value is far from the measured value in χc0->Σ+Σ- channel. In summary ，it also say：“The results for χc0 ->Σ+Σ- and χc0 ->Σ0Σ0 are still inconsistent with the prediction.” What caused this result？ Answer:𝜒𝑐0 → ΣΣത is supposed to be highly suppressed by the helicity selection rule. However, J. Phys. G 38, 035007 (2011) results indicate that the transitions via these kinds of loops as longdistance effects can give significant contributions.

Amit:Can you please explain what is Helicity Selection Rule with a suitable example? Answer:Briefly introduce it.

Ryuta:In the Fig.4 (left), the invariant mass of Sigma+/Sigma-, I could find a small bump-like structure around 3.36-3.37 GeV. If I check that for the case of Sigma+/Pbar/K0short, as you have shown last week, there also would be a similar structure on this region. Answer:No discussion on this.

Xin:Could you briefly explain what is the “color octet mechanism (OCM)” ? Probably with Feynman diagram … Answer:It’s a model in the Non-relativistic Quantum Chromodynamics，(NRQCD), it is used to deal with the decay of the colored heavy quarkantiquark pairs on the short and long distance scale problem.

Yuzhen:In Fig.3 (left), the density of black point in the center is highest, but density of up, underneath, left and right side of the center is a little higher than other places, why? Answer:1, He has selected the clean Λ signals. 2,The width of Λ is very narrow.

Suyu:In right panel of figure 1, what’s the rule to select such the boxes as background? As I remember, you did some similar thing in your analysis. Why some box contributes as 1/4 while others 1/2?

Kai:section V, the PDF of signal peaks including a Gaussian function, why the mean value is set to be zero? Anwser:Actually, if we didn’t set it to be zero, the mean of the shape will shift because of the convolution. Usually we will set it too. otherwise it will give a very small change interval

Next,Liukai introduced Introduction to technical documentation. Finally, Yuhang introduced the motivation about next JC paper.