Effect of higher orbital angular momenta in the baryon spectrum

We have performed a Faddeev calculation of the baryon spectrum for the chiral constituent quark model including higher orbital angular momentum states. We have found that the effect of these states is important, although a description of the baryon spectrum of the same quality as the one given by including only the lowest-order configurations can be obtained. We have studied the effect of the pseudoscalar quark-quark interaction on the relative position of the positive- and negative-parity excitations of the nucleon as well as the effect of varying the strength of the color-magnetic interaction.Comment: 7 pages, 4 figures. To be published in Phys. Rev. C (November 2001

ndnd scattering lengths from a quark-model based NNNN interaction

We calculate the doublet and quartet neutron-deuteron scattering lengths using a nonlocal nucleon-nucleon interaction fully derived from quark-quark interactions. We use as input the $NN$ $^1S_0$ and $^3S_1$-${}^3 D_1$ partial waves. Our result for the quartet scattering length agrees well with the experimental value while the result for the doublet scattering length does not. However, if we take the result for the doublet scattering length together with the one for the triton binding energy they agree well with the so-called Phillips line.Comment: 6 pages, 2 tables. Accepted for publication in Physical Review