Scalar meson exchange and the baryon spectra

Abstract

We explore the role of a scalar meson exchange interaction between quarks in a semirelativistic constituent quark model where the quarks are also subject to a linear confinement. We search for a variational solution and study how the spectrum evolves when the strength of the scalar meson exchange increases. Our results have good implications on the description of the low-lying baryon masses, especially on the long-standing problem of the relative position of the first positive-parity (Roper resonance) and the first orbitally excited states.