Building Diquark Model from Lattice QCD

A novel Lattice QCD (LQCD) method to determine the quark-diquark ($q$-$D$) interaction potential together with diquark mass ($m_D$) is proposed. Similar HAL method, $q$-$D$ determined by demanding it reproduce equal-time Nambu-Bethe-Salpeter (NBS) wave function. To do this, necessary use masses of quark and as inputs, which however are not straightforwardly obtained because color confinement QCD. In this work, that p-wave spectrums from two-point correlators be reproduced potentials for $c$-$\bar{c}$ sectors NBS functions. Numerical calculations performed using 2+1 flavor gauge configurations pion $m_\pi\simeq 700$ MeV generated PACS-CS collaboration. We apply our $c$-$\bar c$ system charm-diquark ($\Lambda_c$ baryon) obtain charm mass, $c$-$D$ potential. Our preliminary analysis leads $m_D \simeq 1.127$ GeV roughly consistent a naive estimate based on constituent picture, i.e., $m_{D} m_{\rho} 1.12$ 2m_N/3 1.06$ GeV.