Abstract. We analyze peculiarities of the Pauli principle in thrre-cluster system. We demonstrated that the antisymmetrization operator, being a source of the three-body interaction, can be decomposed into components involving either permutations between all three clusters, or permutations between two clusters only. Introducing this into the Faddeev equations, one obtains three alternative but equivalent formulations. These sets of equations are presented in operator form, for practical applications we will make use full set of the oscillator functions.
IntroductionThe Resonating Group Method (RGM) is a well-established approach to three-cluster nuclear systems. It leads to both bound and scattering states using a coupled channels approach. It is a rigorous an self-consistent method for taking into account exactly the Pauli principle, but is computationally expensive and has slow convergence properties.The Faddeev formalism on the other hand has no problems dealing with the non-orthogonality of channels, and is much more suitable for implementing the boundary conditions for two-and three-cluster asymptotics. It was also demonstrated repeatedly that the Faddeev approach is computationally more efficient. This led to numerous attempts to extend the Faddeev formalism to three-cluster systems (see for instance). Because of complexity, which arise from the Pauli principle, many of these attempts were concentrated on simplified and approximate treatment of the Pauli principle.The key issue to extend the formalism to three-cluster systems is the correct and full treatment of the Pauli principle. It is well-known that full antisymmetrization leads to nonlocal, energy-dependent inter-cluster interaction. In addition, in a three-cluster system the antisymmetrization operator is a source of three-body interactions originating from the twobody nucleon-nucleon (NN) interaction, but also from the kinetic energy and overlap kernel.We want to address these difficulties by starting from the RGM wave function, and introduce it in the Faddeev equations. This wave function will then exhibit three Faddeev amplitudes, each with their appropriate set of boundary conditions. The antisymmetrization operator is then decomposed into components involving either permutations between all three clusters, or permutations between two clusters only. Introducing this into the Faddeev equations, one obtains three alternative but equivalent formulations.