We used to think we understood protons, but these bedrocks of the atomic nucleus could send our theories of particle physics tumbling.
In the long life of a proton, 10 years is a mere trice. These peerlessly stable particles, the bedrock of the atomic nucleus, are not prone to the decadence and decay of some of their subatomic brethren. Measuring their lifetimes means watching very many of them do very little for a very long time. Our current best estimate is that they survive for upwards of 1029 years - over a billion billion times the age of the universe.
Ten years, though, is what it took for Randolph Pohl and his colleagues to show that the proton is not all it seems. The results of their experiments at the Paul Scherrer Institute (PSI) in Villigen, Switzerland, were published in July last year. The proton hadn't suddenly become less stable. But it was quite a bit smaller than theory or previous experiments allowed (New Scientist, 10 July 2010, p 10).
To read the rest of the article, click here.