Heavy molecules and one-$σ/ω$-exchange model

Abstract

In the framework of the one-boson-exchange model, we explore whether the intermediate and short-range forces from $σ/ω$-exchange can be strong enough to bind heavy molecular states. $Λ_cD(\bar{D})$, and $Λ_cΛ_c(\barΛ_c)$ systems have been studied and compared. We find that the force from $σ$-exchange is attractive and dominant, whereas the $ω$-exchange force not. As a consequence, the S-wave $Λ_cD$, $Λ_cΛ_c$, and $Λ_c\barΛ_c$ can be possible molecular candidates. We further indicate that one hadron-hadron system with more light quarks $(u,d)$ can be easier to form a bound state. As a byproduct, by studying the heavy-quark mass dependence for the $Λ_cD(\bar{D})$-like and $Λ_cΛ_c(\barΛ_c)$-like systems, we find that the charm/bottom sector can easily accommodates molecular states. Finally, the $Λ_cN(\bar{N})$ and $Λ_bN(\bar{N})$ systems are investigated. Our results indicate that they are also likely to form bound states. By including one-$π$-exchange forces providing additional attraction when coupled channels are included, we expect many molecular states in heavy quark sectors.

8 pages, 3 figures, 8 tables