Wu first cited the RR experiment months ahead of its publication

Wu first cited the RR experiment months ahead of its publication

• Mar 18, 2022
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The first of many writings by Wu that reference the Rustad-Ruby work was Beta Disintegration, Allowed and Forbidden Decay, published December 1952 in the journal Physica.

Note that is the very month the first results from the RR experiment were submitted for publication. In fact, Wu’s paper was received by the Dutch scientific journal months earlier, on June 9, 1952, soon after Stan had begun his graduate work at Brookhaven.

Already at that early date, Wu would write:

However the latest results on the 6He recoil experiment *) by using well-defined 6He source is strongly in favor of the tensor interaction. Supplementary experiments are being carried out to check any possible scattering effects.

The footnote reads:

R u b y, S. and R u s t a d, B. Private communication (Columbia Univ. or Brookhaven Nat. Lab.).

Overall, the paper is a review of the state of play in 1952 regarding the interaction form and coupling constants in beta decay. Among the paper’s seven conclusions is this one.

7. Reliable results from nuclear recoil experiments will help to decide between (S, T), (V, A) or (V, T).

Another Wu-connected paper that cited Rustad-Ruby before publication was The Fermi Term in Beta-Neutrino Correlation by Columbia physicist D. C. Peaslee, which was received for publication by The Physical Review one week before the first RR paper appeared in print. 

Peaslee writes:

Measurements of beta-neutrino correlation on He⁶ show that G[amow-Teller]=T[ensor]. One now seeks a suitable use for determining the F[ermi] component by beta-neutrino correlation.

He then proceeds to suggest that "the most favorable parent isotope [to determine the F component] appears to be A³⁵.

That turned out to be prophetic because it was correlation experiments with A³⁵ that later provided some of the first evidence that RR could be wrong. 

With these papers, we see Wu's early promotion of the tensor interpretation, as well as the seed of its later reversal. The fact that both papers preceded the publication of the first RR paper is a sign of the coordination of experimental work in Wu's laboratory.