Determination of theΛmagnetic moment by QCD sum rules

Abstract

The magnetic moment of the Λ hyperon is calculated using the QCD sum-rule approach of Ioffe and Smilga. It is shown that ${\mu }_{\Lambda }$ has the structure ${\mathrm{\mu }}_{\mathrm{\Lambda }}$=(2/3(${\mathrm{e}}_{\mathrm{u}}$+${\mathrm{e}}_{\mathrm{d}}$+${4\mathrm{e}}_{\mathrm{s}}$)(eħ/${2\mathrm{M}}_{\mathrm{\Lambda }}$c)(1+${\mathrm{\delta }}_{\mathrm{\Lambda }}$), where ${\delta }_{\Lambda }$ is small. In deriving the sum rules special attention is paid to the strange-quark mass-dependent terms and to several additional terms not considered in earlier works. These terms are now appropriately incorporated. The sum rule is analyzed using the ratio method. Using the external-field-induced susceptibilities determined earlier, we find that the calculated value of ${\mu }_{\Lambda }$ is in agreement with experiment.