Exploring Three Nucleon Forces in Lattice QCD

We study the three nucleon force in N-f=2 dynamical clover fermion lattice QCD, utilizing the Nambu-Bethe-Salpeter wave function of the three nucleon system. Since parity-odd two nucleon potentials are not available in lattice QCD at this moment, we develop a new formulation to extract the genuine three nucleon force which requires only the information of parity-even two nucleon potentials. In order to handle the extremely expensive calculation cost, we consider a specific three-dimensional coordinate configuration for the three nucleons. We find that the linear setup is advantageous, where nucleons are aligned linearly with equal spacings. The lattice calculation is performed with 16(3)x32 configurations at beta=1.95, m(pi)=1.13GeV generated by CP-PACS Collaboration, and the result of the three nucleon force in triton channel is presented.