Θ+ in a chiral constituent quark model and its interpolating fields

The recently discovered pentaquark Theta(+) is described within the chiral constituent quark model. Within this picture the flavor-spin interaction between valence quarks inverts the (1s)(4) and (1s)(3) (1p) levels of the four-quark subsystem and consequently the lowest-lying pentaquark is a positive parity, I = 0, J = 1/2 state of the flavor antidecuplet, similar to the soliton model prediction. Contrary to the soliton model, however, the quark picture predicts its spin-orbit partner with J = 3/2. Different interpolating fields intended for lattice calculations of Theta(+) are constructed, which have a maximal overlap with this baryon if it is indeed a quark excitation in the 5 Q system. (C) 2003 Published by Elsevier B.V.