Coupled channel analysis of molecule picture of $P_c(4380)$

Abstract

We construct a potential obtained by one-pion exchange for the coupled channel ${\Sigma }_c^{\ast }$$\bar{D}$-${\Sigma }_c$${\bar{D}}^{\ast }$, and solve the coupled Schrödinger equations to determine the binding energy. We find that there exists one or two bound states with the binding energy of several MeV below the threshold of ${\Sigma }_c^{\ast }$ and $\bar{D}$, dominantly made from a ${\Sigma }_c^{\ast }$ baryon and a $\bar{D}$ meson, with the size of about $1.5$fm for wide parameter region. We also study the pentaquark states including a $b$ quark and/or an anti-$b$ quark. We show that there exist pentaquarks including $c\bar{b}$, $b\bar{c}$ and $b\bar{b}$, all of which lie at about $10$MeV below the corresponding threshold and have size of about $1.5$fm.

Comments: 7 pages, 9 figures