Accession Number : AD0437670

Title :   ELECTRON DECAY BRANCHING RATIO OF THE PION,

Corporate Author : COLUMBIA UNIV IRVINGTON-ON-HUDSON N Y NEVIS LABS

Personal Author(s) : Strelzoff,Alan

Report Date : MAR 1964

Pagination or Media Count : 63

Abstract : The ratio of the pion decay rates for the processes, pi yields e + nu and pi yields mu + nu was measured. A large NaI (tl) crystal was used to separate the high energy pion decay electrons from the continuous spectrum of the pi-mu-e chain. Counting decay electrons immediately following a pion stop, the ratio by a direct comparison of pi-e and pi-mu-e electrons was determined. From an observed 10,891 pi-e electrons a precision of 1.8% was attained in the guantity (pion lifetime x branching ratio). Considering the present uncertainty in the pion lifetime the branching ratio, (1.247 = 0.028) x 10 to the -4 power is obtained. This is in good agreement with the theoretical value, 1.233 x 10 to the -4 power, required by the V-A theory when radiative corrections are included. (Author)

Descriptors :   (*PIONS, DECAY SCHEMES), LEPTONS, ELECTRONS, MUONS, NEUTRINOS, NUCLEAR PARTICLES, THEORY, SODIUM COMPOUNDS, IODIDES, CRYSTALS, NUCLEAR RADIATION SPECTROMETERS, SCINTILLATION COUNTERS, MEASUREMENT, MATHEMATICAL ANALYSIS, NUCLEAR RADIATION SPECTROSCOPY

Distribution Statement : APPROVED FOR PUBLIC RELEASE