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arXiv · hep-ph/0506193

Two Nucleon-States in a Chiral Quark-Diquark Model

Keitaro Nagata·Atsushi Hosaka
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Abstract

We study the ground and first excited states of nucleons in a chiral quark-diquark model. We include two quark-diquark channels of the scalar-isoscalar and axial-vector-isovector types for the nucleon states. The diquark correlation violating the spin-flavor SU(4)$_{SF}$ symmetry allows to treat the two quark-diquark channels independently. Hence the two states appear as the superpositions of the two quark-diquark channels; one is the nucleon and the other is a state which does not appear in the SU(4)$_{SF}$ quark models. With a reasonable choice of model parameters, the mass of the excited state appears at around 1.5 GeV, which we identify with the Roper resonance N(1440).

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Keitaro Nagata, Atsushi Hosaka. 2006-01-05. Two Nucleon-States in a Chiral Quark-Diquark Model. https://doi.org/10.1088/0954-3899%2F32%2F6%2F003

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