Pentaquark $Θ^+$ in nuclear matter and $Θ^+$ hypernuclei

Abstract

We study the properties of the $Θ^+$ in nuclear matter and $Θ^+$ hypernuclei within the quark mean-field (QMF) model, which has been successfully used for the description of ordinary nuclei and $Λ$ hypernuclei. With the assumption that the non-strange mesons couple only to the $u$ and $d$ quarks inside baryons, a sizable attractive potential of the $Θ^+$ in nuclear matter is achieved as a consequence of the cancellation between the attractive scalar potential and the repulsive vector potential. We investigate the $Θ^+$ single-particle energies in light, medium, and heavy nuclei. More bound states are obtained in $Θ^+$ hypernuclei in comparison with those in $Λ$ hypernuclei.