Towards high partial waves in lattice QCD with an extended two-hadron operator

An extended two-hadron operator is developed to extract the spectra of irreducible representations (irreps) in the finite volume. The irreps of the group for the finite volume system are projected using a coordinate-space operator. The correlation function of this operator is computationally efficient to extract lattice spectra of the specific irrep. In particular, this new formulation only requires propagators to be computed from two distinct source locations, at fixed spatial separation. We perform a proof-of-principle study on a 243 ?? 48 lattice volume with m7v ??? 900 MeV by isolating various spectra of the 7v7v system with isospin-2 including a range of total momenta and irreps. By applying the L??scher formalism, the phase shifts of S- and D-wave 7v7v scattering with isospin-2 are extracted from the spectra, with a tentative look at the role and influence of the G-wave.

Automated summary

An extended two-hadron operator is developed to extract spectra of irreducible representations in the finite volume. The phase shifts of S-wave and D-wave 7v7v scattering are extracted from lattice spectra using the Lüscher formalism.