Abstract
We derive covariant equations describing the three-quark bound state in terms of quark and diquark degrees of freedom. The equations are exact in the approximation where three-body forces are neglected. A feature of these equations is that they unify two often-used but seemingly unrelated approaches that model baryons as quark-diquark systems; namely, (i) the approach using Poincaré covariant quark+diquark Faddeev equations driven by a one-quark-exchange kernel [pioneered by Cahill et al., Aust. J. Phys. 42, 129 (1989) and Reinhardt, Phys. Lett. B 244, 316 (1990)], and (ii) the approach using the quasipotential quark-diquark bound-state equation where the kernel consists of the lowest-order contribution from an underlying quark-quark potential [pioneered by Ebert et al., Z. Phys. C 76, 111 (1997)]. In particular, we show that each of these approaches corresponds to the unified equations with its kernel taken in different, nonoverlapping, approximations.
Original language | English |
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Article number | 054016 |
Number of pages | 6 |
Journal | Physical Review D |
Volume | 108 |
Issue number | 5 |
DOIs | |
Publication status | Published - 1 Sept 2023 |
Keywords
- Bethe-Salpeter equation
- Bound states
- Feynman diagrams
- Quantum field theory
- Quark model