Nucleon-delta Mass Research Articles

On the [formula omitted] corrections to hadron masses

The strong coupling limit of lattice QCD is reviewed and the important corrections of order 1 g 2 to the pion, rho, nucleon and delta masses are computed with Wilson's fermion method. The nucleon-delta mass difference is obtained by decomposing the baryon field into independent fields transforming in irreducible representations of the rotation-flavor group.

Does chiral symmetry breaking cause the Nucleon-Delta mass difference?

We critically review recent calculations of the Nucleon-Delta mass splitting in the QCD sum rule approach. Some calculations indicate aN-Δ mass splitting already to zeroth order QCD, i.e., only due to the chiral symmetry breaking quark condensate. We show that there is no indication of a mass splitting to zeroth order if optimal interpolating fields are used for theN and Δ, where optimal fields are those for which the continuum contribution is minimal.

Why the neutron isn't all neutral

Experimental measurements of the electric form factor of the neutron indicate a spatially inhomogeneous distribution of charge. The quark model, with a spatially dependent spin-spin interaction, can accurately describe this inhomogeneity. We relate the neutron's charge radius to the nucleon-delta mass difference and discuss other experimental consequences of the inhomogeneity.