Positive-parity Excited Baryons Research Articles

Photoproduction of Positive-Parity Excited Baryons in the1/NcExpansion of QCD

We analyze the photoproduction helicity amplitudes for positive-parity excited baryons in the context of the $1/{N}_{c}$ expansion of QCD. The results show that subleading corrections in $1/{N}_{c}$ are important and that, while one-body effective operators are dominant, there is some evidence for the need for two-body effects.

Ground-state and low-lying positive-parity excited baryons containing u, d, s, c and b quarks in a consistent quark model with chromodynamics

A quark model suggested by quantum chromodynamics is used to calculate the entire spectrum of ground-state and low-lying positive-parity excited baryons containing u, d, s, c and b quarks. The only input parameters aside from Δ(1950) are ground-state masses.

Nonleptonic hyperon decays-wave amplitudes and negative-parity excited baryons

The contribution of negative-parity excited baryons is calculated and found to be small relative to other contributions (i.e. the equal-time commutator and the vector-meson pole) which have been successfully employed in the recent past. While positive-parity excited baryons help to explainp-wave (B) amplitudes, 1/2− baryon poles do not spoil the existing description ofs-wave (A) amplitudes.

Erratum: Positive-parity excited baryons in a quark model with hyperfine interactions

A quark model suggested by quantum chromodynamics with strong spin-dependent forces of magnetic-dipole-magnetic-dipole character perturbing a flavor-independent confinement potential is applied to lowlying positive-parity excited baryons. SU(3) is broken only by quark masses, and this leads to a new choice of basis states in the hyperon sector; couplings to $\overline{K}N$ are especially transparent in this basis. The results, which are largely determined by previous analyses, are in good agreement with the known properties of these states. Spin-orbit forces are once again found to be negligible.

Positive-parity excited baryons in a quark model with hyperfine interactions

A quark model suggested by quantum chromodynamics with strong spin-dependent forces of magnetic-dipole-magnetic-dipole character perturbing a flavor-independent confinement potential is applied to lowlying positive-parity excited baryons. SU(3) is broken only by quark masses, and this leads to a new choice of basis states in the hyperon sector; couplings to $\overline{K}N$ are especially transparent in this basis. The results, which are largely determined by previous analyses, are in good agreement with the known properties of these states. Spin-orbit forces are once again found to be negligible.