Wave Function of the Roper from Lattice QCD

Understand

We apply the eigenvectors from a variational analysis in lattice QCD to successfully extract the wave function of the Roper state, and a higher mass P_11 state of the nucleon.

• We use the 2+1 flavour 32^3x64 PACS-CS configurations at a near physical pion mass of 156 MeV.
• We find that both states exhibit a structure consistent with a constituent quark model.
• The Roper d-quark wave function contains a single node consistent with a 2S state, and the third state wave function contains two, consistent with a 3S state.