Madame Wu and the backward Universe

(Since my weekly round-up experiment seems to have failed horribly, I’m going to try to go back to linking and summarizing individual articles I’ve written around the web on this blog. We’ll see if I keep it up!)

The great physicist Chien-Shiung Wu in 1958. [Credit: Smithsonian Institution]
The great physicist Chien-Shiung Wu in 1958. [Credit: Smithsonian Institution]
Chien-Shiung Wu is one of those physicists that everyone should know about, but not enough do. A veteran of the Manhattan Project, she went on to become the world’s expert on beta decay: the process by which an atomic nucleus changes into another element, emitting an electron (or positron) in the process. In the 1950s, she realized beta decay would be a way to test a fascinating new theory of the weak force, which predicted that there should be a fundamental asymmetry between processes occurring in different directions. Her experiment was the first observation of parity violation, which opened up a wealth of new results, leading ultimately to the discovery of the Higgs boson.

For Double X Science, I commemorated this discovery, explaining why it’s important and how weird it is. It would seem that the laws of physics shouldn’t depend on which direction a process occurs, yet that’s the way the Universe works!

Wu realized she could test this idea in the lab after discussions with her colleagues Tsung-Dao Lee and Chen-Ning Yang, who laid the theoretical groundwork for understanding the weak force. She recruited Henry Boorse, Mark Zemansky, and Ernest Ambler, who were skilled at experiments at very low temperatures. It’s a great illustration of the collaborative nature of science: Lee and Yang provided theoretical knowledge, but needed Wu to design and perform the experiment; Wu in her turn brought in experts in low-temperature physics to provide expertise in an area unfamiliar to her. (On a more sour note, Lee and Yang won the Nobel Prize for the discovery of parity violation, but Wu and her fellow lab workers were passed over.) [Read more…]

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