ΩandΣ0Λtransition magnetic moment in QCD sum rules

Abstract

The method of QCD sum rules in the presence of the external electromagnetic F µν field is used to calculate the Ω magnetic moment µ Ω and the Σ 0 Λ transition magnetic moment µ Σ 0 Λ , with the susceptibilities obtained previously from the study of octet baryon magnetic moments. The results µ Ω = −1.92µ N and µ Σ 0 Λ = 1.5µ N are in good agreement with the recent experimental data.Keywords: magnetic moment, QCD sum rules PACS: 13.40. Em, 14.20.Jn, 12.38.Lg According to the quark model the Ω − is composed of three strange quarks with parallel spins. This state is particularly interesting because of the large symmetry breaking that can not be accomodated consistently in the naive quark model. In Ref.[1], it has been shown that nonstatic baryon-dependent magnetic effects are large. In this paper we investigate these symmetry breaking effects and evaluate the Ω moment in the QCD sum rule [3]. The Ω moment has been studied in literaures [2] and various theoretical results range from −1.3µ N to −2.7µ N . We find our result is in good agreement with the recent data [4,5].In a typical hadronic scale the quantum chromodynamics (QCD) is highly nonperturbative which makes a direct analytical first-principle calculation impossible. In this work we adopt the method in the presence of an external electromagnetic field [6,7]

Octet baryon magnetic moments from QCD sum rules

“…We have µ ′ d = −1.12(39) < −0.51 (8). It also agree very well with the experimental moments µ ′ d = −1.003 < −0.578(26) although the two sides of this sum don't agree well.…”

“…For µ d , in n it is −1.15(11) while for Σ 0 is −0.82(8) and for Σ − is −0.93 (8). From p we can get µ (12).…”

Relativistic quark model for theΩ−electromagnetic form factors

“…The combination of the two results leads to µ Ω − = (−2.019 ± 0.054)µ N [1,14]. Several works followed with estimations of µ Ω − [15,16,17,18,19,20,21,22,23,24,25,26,27,28,29]. The Ω − electric quadrupole moment was also predicted [22,23,30,31,32,33,34,35,36,37,38,39,40], although there is no experimental result.…”

“…The differences between Eqs. (18)- (19) and the corresponding expressions in Ref. [58] are the baryon mass M B (which replaces M ∆ ) andẽ B andκ B (which replaceẽ ∆ and κ ∆ ).…”

Transition magnetic moment ofΛ→Σ0in QCD sum rules

“…Calculations of the regular baryon magnetic moments have been carried out in QCD sum rules [2][3][4][5][6][7][8]. Limited study of the Λ → Σ 0 transition magnetic moment was performed in the traditional QCD sum rule approach [9], and in the light-cone formulation of the approach [10].…”