{Delta}(1232) and the polarizabilities of the nucleon

Journal Article · Thu May 01 04:00:00 EDT 1997 · Physical Review, D

DOI:https://doi.org/10.1103/PhysRevD.55.5598· OSTI ID:562457

Hemmert, T R ^[1]; Holstein, B R ^[2]; Kambor, J ^[3]

---

1. Theory Division, TRIUMF, 4004 Wesbrook Mall, Vancouver, British Columbia, V6T 2A3 (CANADA)
2. Department of Physics and Astronomy, University of Massachusetts, Amherst, Massachusetts 01003 (United States)
3. Theoretische Physik, Universitaet Zuerich, CH-8057 Zuerich (Switzerland)

Previous calculations of the polarizabilities of the nucleon within the framework of heavy baryon chiral perturbation theory have included the contribution of the {Delta}(1232) only in its effects on various contact terms or have been performed in chiral SU(3) where systematic errors are difficult to control. Herein, we perform a corresponding calculation in chiral SU(2) wherein {Delta}(1232) is treated as an explicit degree of freedom and the expansion is taken to third order in soft momenta, the pion mass, and the quantity M{sub {Delta}}{minus}M{sub N}, collectively denoted {epsilon}. We present the results of a systematic O({epsilon}{sup 3}) calculation of forward Compton scattering off the nucleon, extract the electric polarizability {bar {alpha}}{sub E}, the magnetic polarizability {bar {beta}}{sub M}, and the spin polarizability {gamma}, and compare with available information from experiments and from previous calculations. Concluding with a critical discussion of our results, we point out the necessity of a future O({epsilon}{sup 4}) calculation. {copyright} {ital 1997} {ital The American Physical Society}

• OSTI ID: 562457
• Journal Information: Physical Review, D, Journal Name: Physical Review, D Journal Issue: 9 Vol. 55; ISSN PRVDAQ; ISSN 0556-2821
• Country of Publication: United States
• Language: English

Related Subjects

66 PHYSICS
CHIRAL SYMMETRY
COMPTON EFFECT
DELTA-1232 BARYONS
NUCLEONS
PERTURBATION THEORY
PHOTON-NUCLEON INTERACTIONS
POLARIZABILITY
SPIN
SU-2 GROUPS
SU-3 GROUPS