Lambda Polarization in Exclusive - and Photoproduction at Clas

The CLAS collaboration at JLab has recent results on Λ polarization for both electroproduction and photoproduction of K⁺Λ exclusive states. I note the striking phenomenological trends in the data and discuss the underlying physics which might give rise to these phenomena; both in the context of an effective Lagrangian formalism, where the degrees of freedom are intermediate mesons and baryons, and also in the context of a simple quark picture. The quark model argument leads to the conclusion that the s and bar s quarks are produced with spins anti-aligned, in apparent contradiction to the popular ³P₀ model of quark pair creation in which the pair is created with vacuum quantum numbers (J=0 and positive parity), i.e. in an S=1, L=1, J=0 angular momentum state.