When I first worked with him, [Gene Commins] was a grad student, and then he was an instructor. He worked under—with Polykarp Kusch. It was Kusch’s lab. But Gene just liked doing it. And they made you feel a part of the lab. I made use of my experience there. I’ve written chapters about [laugh] some of them in my later work. It was just very formative, if you will. I was sorry, in some sense that when—after I graduated, they wouldn’t let me work in the lab anymore. They needed the spaces for other students.

Zierler: And I’m curious, Allan, how did you develop an interest in the theory of weak interactions? Where did that come from? ....

Franklin: Well, what got me interested in looking at it, well, there were a couple of things. Parity violation was a big thing, made a [laugh] big impression on me. I was an undergraduate at Columbia when it was announced....They stopped classes.

Zierler: [laugh]

Franklin: They stopped physics classes to announce the experimental results. That always had a big effect on me. And also, when I learned more and started working in history and philosophy, there was a problem. When the V-A theory was proposed, there were three experiments that disagreed with it. And I was interested in why did they do that. Why did they propose a theory that was known to be refuted?

And so then I had to—then I went into—I had to do the history of how did we get to V-A, that there were good reasons for believing V-A, so there were reasons for questioning the experimental results. And they all turned out to be wrong, which was suggested interestingly by the theorists, Feynman and Gell-Mann and Marshak and Sudarshan. So, you know, it was an interesting historical question and philosophical—why do you propose a theory that’s known to be refuted?

Zierler: Yeah. So what’s the answer?

Franklin: ....Well, when you have a disagreement between theory and experiment, theory could be wrong, experiment could be wrong, or they both could be wrong.

Zierler: Sure. [laugh]

Franklin: And they can’t both be right. And so in this case, it turned out of course that the experimental results were incorrect.... [I]n the case of V-A, there were lots of things that V-A had going for it. And so people said, “Well, maybe we ought to redo those experiments.” Now that leads you to my current work, or my most recent work, [which] is, do experiments need to be replicated?

The implications of these results can now be combined with the conclusions of Adler's summary (Session VI) by adding to his list of experiments: V. Non-classical recoil experiments. 

This in combination with the polarization results (Alder I), indicates that the G-T interaction is A, in direct contradiction with results of classical recoil experiments for He⁶ and Ne¹⁹. The observed interference between the Fermi and GT-parts of the interaction in ß-γ polarization correlation experiments (Alder II) leads to the consulsion that if the FT-interaction is A, the Fermi interaction must be V.

The A and V assignments are in agreement with two-component theory and also with other new theories. [Sudarshan-Marshak and Feynman-Gell-Man are cited.]

t t Formerly at Columbia University at BrookhavenNational Laboratory, now deceased.

The experimenters and technicians associated with this work express their sorrow at the untimely death of Brice Rustad and offer their condolences to his wife, Mrs. Mary Rustad.

T.D. LEE:

We next turn to the Universal Fermi Interaction, which is an attempt to gain a more unified understanding of certain of the weak interactions. We draw the famous triangle representing the interactions of interest:

Beta decay information tells us that the interaction between ( ^p-i v\ ) and ( £ V ) is scalar and tensor, while the two-component neutrino theory plus the law of conservation of leptons implies that the coupling between ( V ) and ( /^y V ) is vector. This means that the Universal Fermi Interaction cannot be realized in the way we have expressed it. If all these coupling types turn out to be experimentally correct, we prefer to think that the similarity in coupling constants cannot be accounted for in terms of such a limited scheme. Rather it is a universal feature of all weak interactions, and not just those involving leptons. Nevertheless, at this moment it is very desirable to recheck even the old beta interactions to see whether the coupling is really scalar, a point to which we shall return later….

C.S. WU :

First, we may place an upper limit on the contribution from the Z-dependent Coulomb part, using the data supplied by the e-ν angular correlation in the decay of He⁶. Since Z = 28, α = 1/137 , and the He⁶ data indicates that the remaining factor is less than 2 /√3, the Z-dependent term is less than 0.23. Therefore most of the asymmetry is provided by the first term. But such a term exists only if neither charge conjugation nor parity are conserved, so the experiment already demonstrates the noninvariance of C and P.

The evidence on the relative strengths of scalar and vector components in the Fermi interaction is no longer so convincing as we previously had thought, because we don f t know if time reversal invariance holds true. The old methods used beta-neutrino angular correlations to determine the nature of the interactions. For example He⁶, which decays through a pure G. T. interaction, was used to show that this interaction is mostly tensor. Ne¹⁹ was used to investigate the Fermi interaction, but since here a mixture of Fermi and G . T . interactions is involved, this method turned out to be not very sensitive. The decay of A³⁵ would furnish a much more sensitive test, because here I IMgr M p j 1 ^ l/atf Knowledge about the exact nature of the Fermi interaction, i . e . the relative strength of C and C v , becomes essential when we wish to select the best experimental method of testing time reversal invariance.

Nowadays we no longer need to use the beta-neutrino angular correlation method, which is difficult and insensitive. As Prof. Lee has pointed out, the longitudinal polarization of electrons from scalar, pseudo-scalar, and tensor interactions is different from the longitudinal polarization of electrons coming out of vector and axial vector interactions. Therefore it would be most interesting to investigate the longitudinal polarization of electrons coming from pure Fermi decays, i . e . 0 } 0 transitions, of which there are many.

Parity violation threw a sudden and dramatic spotlight on the weak interaction—or rather, whether such a thing as the weak interaction existed. At the Rochester conference in April 1957, Wu described a still unpublished experiment, by her students Brice Rustad and Stanley Ruby, at the BGRR suggesting that beta decay, the prototypical weak interaction, might have different forms and therfore could actually be the product of several forces. One piece of evidence for this had to do with the spin of the neutrinos emitted in beta decay. Mor exactly, it had to do with wat is called the helicity of the neutrinos, or their spin relative to the direction of motion....The experiment described by Wu suggested bea-decay neutrinos could be right-janded, which implied in turn that beta decay itself had different forms and was not one force.

When Leonard Schiff, Chariman of the physics department at Stanford began organizing the program for an APS meeting to be held just before Christmas 1957, he cast about for someone to survey the beta-decay problem. Maurice Goldhaber's name leapt to mind....Goldhaber recalled:

My first inclination was to say no, because I had not worked on beta spectra. My second inclination was that it would do me a lot of good to read these contradictory papers. I accepted, got the key reprints together, and stayed home one Friday morning in mid-October to read them. Before I finished the first paper, I thought, "There must be a better way to do this." Twenty minutes later, I had thought of one.