Speaker
Fangzheng Peng
(buaa)
Description
With the description that for a pure molecule state the effective range $r_0$ should satisfy the condition of $r_0 > 0$ and the fact that $r_0$ could be matched with the couplings related to momentum term in contact field theory, we can fit the low energy couplings up to NLO in the contact effective theory describing the 3 $P_c$ pentaquarks observed by LHCb in 2019 and finally get the effective range $r_0$. By comparing the sign of $r_0$, the spin of $P_c (4440)$ and $P_c (4457)$ could be distinguished, providing the conclusion that under the molecule picture, it's more natural to take $P_c(4440)$ as the $J^P=\frac{1}{2}^-$ $D^* \Sigma_c$ molecule and $P_c(4457)$ the $J^P=\frac{3}{2}^-$ one.
Primary author
Fangzheng Peng
(buaa)
