Quark mass dependence of H-dibaryon in $\Lambda\Lambda$ scattering

摘要

We study the quark mass dependence of the H-dibaryon in the strangeness$S=-2$ baryon-baryon scattering. A low-energy effective field theory is used todescribe the coupled-channel scattering, in which the quark mass dependence isincorporated so as to reproduce the lattice QCD data by the HAL QCDcollaboration in the SU(3) limit. We point out the existence of theCastillejo-Dalitz-Dyson (CDD) pole in the $\Lambda\Lambda$ scattering amplitudebelow the threshold in the SU(3) limit, which may cause the Ramsauer-Townsendeffect near the $N\Xi$ threshold at the physical point. The H-dibaryon isunbound at the physical point, and a resonance appears just below the $N\Xi$threshold. As a consequence of the coupled-channel dynamics, the poleassociated with the resonance is not continuously connected to the bound statein the SU(3) limit. Through the extrapolation in quark masses, we show that theunitary limit of the $\Lambda\Lambda$ scattering is achieved between thephysical point and the SU(3) limit. We discuss the possible realization of the"H-matter" in the unphysical quark mass region.