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A systematic study of muon capture

University of British Columbia

Negative mucn lifetimes have been measured in 48 elements including four pairs of separated isotope targets (⁶Li, ⁷Li, ¹⁰B, ¹¹B, ¹²C, ¹³C, ¹⁶O, ¹⁸O) . The experimental set-up and electronics logic were checked against the positive muon lifetime, wiich was measured to be 2197,0±0.7 ns, in good agreement with the accepted value of 2197.120±0.077 ns. Muons were produced by the backward decay of pions which were provided by the M20 beam channel at TRIUMF. The negative muon lifetimes were measured for all light elements except H and He. An improved accuracy has been achieved in Be, N, 0, F, Na, Cl, and K, and new measurements were performed for ¹³C, ¹⁸O, Dy and Er. Strong isotope effects were observed in Li, B, and O, but there was no isotope effect in C. Our results in ⁶Li and ⁷Li were in good agreement with the predicted values by Lodder and Jonker. Our measurements confirm that the even-odd effect in heavy nuclei is not strong and the increase of the odd-Z capture rates is smaller than that expected from the quenching of the Cabibbo angle in large magnetic fields. The negative muon beam was also stopped in 23 metallic oxides in order to measure the atomic capture ratios. The number of muons captured by each element was deduced by lifetime analysis. Our result reproduced the periodic dependence and agreed well with earlier X-ray measurements. The results however are of higher accuracy and are liable to very different systematic errors, which gives added confidence to the overall situation.

Text

2010-03-23

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http://hdl.handle.net/2429/22389

Physics

University of British Columbia

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