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Geoff Greene Featured in Scientific American Neutron Mystery Article, Video

April 14, 2016

Despite decades of trying, scientists have not been able to definitively measure how long neutrons live outside of atomic nuclei —the best experiments in the world produce conflicting results. Image Credit: Bill Mayer

How a neutron’s life ends is not a mystery to physicists. Exactly when that happens, however, is a much trickier puzzle to solve.

Working on opposite sides of the Atlantic and using two different methods, scientists have conducted the most precise experiments in the world to figure out when neutrons will meet their demise. Even with repeated attempts, they arrive at results that differ by nine seconds. The editors of Scientific American took notice and invited UT Physics Professor Geoff Greene and his colleague Peter Geltenbort to write about this riddle for their magazine. Their take on these studies is laid out in “The Neutron Enigma,” published in the April 2016 issue.

“At any given time, any neutron, no matter how long it’s been there, has an equal probability of decaying in the next one second,” Greene said. “And that’s what we believe describes radioactive decay; it’s totally random. A neutron that’s been around for an hour is just as likely to decay in the next second as one that’s been around for a microsecond.”

The Scientific American also created a video, Quantum Cuteness: Neutron Beta Decay, using a toy gift Greene sent its writers.

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