Luke Yuan

Luke Yuan, the husband and Chien-Shiung Wu, was an experimentat high-energy physicist at Brookhaven National Laboratory. 

A Critical Examination of the He-6 Recoil Experiment of Rustad and Ruby

C. S. Wu and A. Schwarzschild
Columbia University Dept. of Physics internal report
Apr 21 1958

Wu repudiates Rustad-Ruby experiment in unpublished CU-173 Columbia University report. Franklin says letter from Wu to Cavanaugh suggests reexamination was done in November.


The latest results of A-35 strongly indicate a vector-interaction in Fermi transition. The evidence of the recoil experiment of He-6 by Rustad and Ruby has been considered rather conclusively for tensor interaction. So here we are in a predicament!  
It is therefore highly desirable to look carefully into the He-6 experiment and decide whether any systematic errors due to oversight could have affected their interpretation

The following is a report of such an investigation, and the conclusion is that unfortunately some corrections which the authors neglected in their calculations turned out to be quite substantial and rendered the conclusion which they originally made definitely questionable.

The purpose of the re-examination is to point out the detrimental effects on the correlation results due to the presence of even a small quantity of He-6 gas in the diaphragm holes. Furthermore, by using an optical analog it has been possible to infer directly the pressure gradient of He-6 along the chimney hole and therefore substantiate our supposition. This is, unfortunately, what happened.

Acknowledgments. We wish to thank Dr. Richard Garwin and Dr. Luke Yuan for many valuable discussions concerning the measurement of the gas pressure gradient. We particularly want to thank Mr. K. Lattemann for his patient help in carrying out the investigation of the angular variation effect. To Mr. B. Rustad and Mr. S. Ruby we express our thanks for their cooperation. 

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