Precision measurement of the Σ0hyperon mass

Using pp→p+ all charged particles at 800 GeV/c and 27.5 GeV/c incident protons at Fermilah and Brookhaven, respectively, the mass of the Σ 0 hyperon has been measured with an uncertainty of 7 times smaller than the best previous result. This result, M Σ 0 =1192.65±0.020±0.014 MeV/c 2 is based on 16 times the statistics of previous results.