Why does lead behave so differently from every other atomic nucleus when struck by electrons? A team of physicists at Johannes Gutenberg University Mainz (JGU) has taken an important step toward answering this question, only to find that the mystery is even deeper than previously thought. The findings were published in the journal Physical Review Letters.

Electrons usually scatter from atomic nuclei in ways that can be predicted with remarkable accuracy. One well-tested feature is that flipping the spin of the incoming electrons should slightly change the scattering pattern, an effect driven by the exchange of two “virtual photons” between the electron and the nucleus.

For most nuclei, theory predicts exactly how large this tiny effect should be, and decades of experiments have confirmed those predictions. Lead, however, has always stood out. Earlier measurements performed at the U.S. Department of Energy’s Thomas Jefferson National Accelerator Facility showed that, for lead, this spin-dependent effect seemed to vanish entirely, a result that no existing theory could explain.

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I want to read you an email that I was asked to keep confidential because I think it explains some of my worries about academia.

The Nature Physics comment is here: https://www.nature.com/articles/nphys4079

I knew that physicists would go on to argue I should have tried to solve the problem internally (within the community) before drawing public attention to it. The reason I published this comment was so that I could later demonstrate that I did this. This is why it’s a paywalled publication that you don’t find on the arxiv. But just by accident and totally unrelated here is another link:

https://www.dropbox.com/scl/fi/5o31k2jovu4nmyy219tzh/nphys40…22uph&dl=0

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