Measurement of the π0 Mass, and Search for a π00 Gettner, M. ; Holloway, L. ; Kraus, D. ; Lande, K. ; Leboy, E. ; Selove, W. ; Siegel, R. Abstract Publication: Physical Review Letters Pub Date: June 1959 DOI: 10.1103/PhysRevLett.2.471 Bibcode: 1959PhRvL...2..471G