Measurement of theΣ+Magnetic Moment

Abstract

Approximately 370 000 pictures of slow $K^{-}$ interactions were taken in the Michigan-Argonne propane bubble chamber at the Argonne National Laboratory Zero-Gradient Synchrotron. They were scanned for the reaction $K^{-}p\to {\Sigma }^{+}{\pi }^{-}$ produced by $K^{-}$ in the momentum range 250-550 MeV/c. A 45-kG magnetic field applied perpendicular to the incident beam precessed the spin of the ${\Sigma }^{+}$ through an average angle of 9°. The final sample, after cuts, consisted of 2651 events with an average time of flight of 1.5 × ${10}^{-10\mathrm{}}$ sec and an average polarization of 0.37. A maximum-likelihood analysis yielded 2.7 ± 0.9 nuclear magnetons for the ${\Sigma }^{+}$ magnetic moment.