P11 and S11 Resonances in Multichannel πN Scattering

Recently several independent experiments have found evidence for the extremely narrow Θ⁺(1540) pentaquark state. Several models suggest that this state has spin-parity 1/2^±, although neither of these quantum numbers have yet been measured experimentally. The Θ⁺(1540) is expected to have an N* pentaquark partner with the same quantum numbers. For that reason, we have taken a fresh look at the P₁₁ and S₁₁ πN scattering amplitudes to see if there are any suggestions of narrow states, or extra states beyond those expected as q³ configurations.