Few-Body Systems

, Volume 49, Issue 1–4, pp 111–119 | Cite as

Electromagnetic Structure of the Δ Baryon within the Covariant Spectator Theory

  • M. T. PeñaEmail author
  • G. Ramalho
  • Franz Gross


We calculated all the electromagnetic observables for the nucleon and its lowest-lying Δ(1232) excitation within a constituent quark model for those two baryons based on the covariant spectator theory. Once the reactions γ NN and γ N → Δ were described, we predicted without further adjusting of parameters the four electromagnetic Δ form factors: the electric charge G E0, the magnetic dipole G M1, the electric quadrupole G E2 and the magnetic octupole G M3. The results are compatible with the available experimental data and recent lattice QCD data.


Form Factor Constituent Quark Electromagnetic Form Factor Transition Form Factor Constituent Quark Model 
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  1. 1.
    Gross F., Ramalho G., Pena M.T.: A pure S-wave covariant model for the nucleon. Phys. Rev. C 77, 015202 (2008)ADSCrossRefGoogle Scholar
  2. 2.
    Gross F., Ramalho G., Pena M.T.: Fixed-axis polarization states: covariance and comparisons. Phys. Rev. C 77, 035203 (2008)ADSCrossRefGoogle Scholar
  3. 3.
    Ramalho G., Pena M.T., Gross F.: A covariant model for the nucleon and the Δ. Eur. Phys. J. A 36, 329 (2008)ADSCrossRefGoogle Scholar
  4. 4.
    Ramalho G., Pena M.T., Gross F.: D-state effects in the electromagnetic N-delta transition. Phys. Rev. D 78, 114017 (2008)ADSCrossRefGoogle Scholar
  5. 5.
    Ramalho G., Pena M.T.: Nucleon and gamma N-delta lattice form factors in a constituent quark. J. Phys. G 36, 115011 (2009)ADSCrossRefGoogle Scholar
  6. 6.
    Ramalho G., Pena M.T.: Valence quark contribution for the gamma N → delta quadrupole transition. Phys. Rev. D 80, 013008 (2009)ADSCrossRefGoogle Scholar
  7. 7.
    Ramalho G., Pena M.T.: Electromagnetic form factors of the delta in a S-wave approach. J. Phys. G 36, 085004 (2009)ADSCrossRefGoogle Scholar
  8. 8.
    Ramalho G., Pena M.T., Gross F.: Electric quadrupole and magnetic octupole moments of the delta. Phys. Lett. B 678, 355 (2009)ADSCrossRefGoogle Scholar
  9. 9.
    Ramalho G., Pena M.T., Gross F.: Electromagnetic form factors of the delta with D-waves. Phys. Rev. D 81, 113011 (2010)ADSCrossRefGoogle Scholar
  10. 10.
    Amsler C. et al.: [Particle Data Group]: Review of particle physics. Phys. Lett. B 667, 1 (2008)ADSCrossRefGoogle Scholar
  11. 11.
    Buchmann A.J., Henley E.M.: Intrinsic quadrupole moment of the nucleon. Phys. Rev. C 63, 015202 (2001)ADSCrossRefGoogle Scholar
  12. 12.
    Blanpied G. et al.: N-delta transition and proton polarizabilities from measurements of p(gamma polarized, gamma), p (gamma polarized, pi 0), and p(gamma polarized pi +). Phys. Rev. C 64, 025203 (2001)ADSCrossRefGoogle Scholar
  13. 13.
    Julia-Diaz B., Lee T.S., Sato T., Smith L.C.: Extraction and interpretation of gamma N-delta form factors within a dynamical model. Phys. Rev. C 75, 015205 (2007)ADSCrossRefGoogle Scholar
  14. 14.
    Alexandrou C., Koutsou G., Neff H., Negele J.W., Schroers W., Tsapalis A.: The nucleon to delta electromagnetic transition form factors in lattice QCD. Phys. Rev. D 77, 085012 (2008)ADSCrossRefGoogle Scholar
  15. 15.
    Gockeler M., Hemmert T.R., Horsley R., Pleiter D., Rakow P.E.L., Schafer A., Schierholz G.: [QCDSF Collaboration] Nucleon electromagnetic form factors on the lattice and in chiral effective field theory. Phys. Rev. D 71, 034508 (2005)ADSCrossRefGoogle Scholar
  16. 16.
    Alexandrou C. et al.: Quark transverse charge densities in the Δ(1232) from lattice QCD. Nucl. Phys. A 825, 115 (2009)ADSCrossRefGoogle Scholar
  17. 17.
    Geng L.S., Camalich J.M., Vicente Vacas M.J.: Electromagnetic structure of the lowest-lying decuplet resonances in covariant chiral perturbation theory. Phys. Rev. D 80, 034027 (2009)ADSCrossRefGoogle Scholar
  18. 18.
    Alexandrou C., Korzec T., Leontiou T., Negele J.W., Tsapalis A.: Electromagnetic form factors of the delta baryon. PoS LAT2007, 149 (2007)Google Scholar
  19. 19.
    Boinepalli S., Leinweber D.B., Moran P.J, Williams A.G., Zanotti J.M., Zhang J.B.: Precision electromagnetic structure of decuplet baryons in the chiral regime. Phys. Rev. D 80, 054505 (2009)ADSCrossRefGoogle Scholar

Copyright information

© Springer-Verlag 2010

Authors and Affiliations

  1. 1.Centro de Física Teórica de Partículas and Dpt. of Physics, Instituto Superior TécnicoUniversidade Técnica de LisboaLisboaPortugal
  2. 2.Thomas Jefferson National Accelerator FacilityNewport News, VirginiaUSA

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