Magnetic moment of the Omega(-) in QCD sumrule (QCDSR)

The Omega(-) magnetic moment (mu(Omega)) was measured very accurately and i t differs from most of the theoretical estimates, thus posing a challenge t o the latter. There are two existing calculations of the magnetic moment [F . X. Lee, Phys.Lett. B 419 (1998) 14, hep-ph/9707411; S. Zhu, W. Y. P. Hwan g and Z. Yang, Phys. Rev. D 57 (1998) 1527, hep/ph 9802322] using QCDSR. Th e first is a careful theoretical study which underestimates the( mu(Omega)) We revisit this calculation, using condensate parameters which were obtain ed from fitting the differences ( mu(p)-mu(n)), (mu(Sigma+)-mu(Sigma-)) and (mu(Xi 0)-mu(Xi-)) [J. Dey, M. Dey and M. Sinha Roy, Phys. Lett. B 443 (19 98) 293] and confirm the experimental number. The mu(Delta++) is also found to agree with the experimental estimate. We conclude that there is no disc repancy between experiment and theory. The second QCDSR calculation reports agreement with experimental (mu(Omega)) and it is found that this is incon sistent with the octet baryon magnetic moment differences investigated by D ey et al. [J. Dey, M. Dey and M. Sinha Roy, Phys. Lett. B 443 (1998) 293] a nd is unreliable. (C) 2000 Published by Elsevier Science B.V. All rights re served.