已有 631 次阅读 2018-2-13 19:13 |个人分类:科学感想|系统分类:博客资讯


On Tuesday (Feb. 6), a collaboration of 190 scientists operating at Fermi National Accelerator Laboratory in Illinois began using an array of magnets arranged in a ring 50 feet (15 meters) in diameter to make one of the most precise measurements ever performed. In this research, called the g-2 experiment (pronounced "g minus 2"), or just g-2 for short, scientists will measure what is called the anomalous magnetic moment of the rare subatomic particle called a muon, which is a heavy cousin of the electron and spins sort of like a top. The muon, however, exists for only 2.2 millionths of a second when at rest.

The magnetic moment, essentially a measurement of the strength of the magnet created by each muon, has been both measured and calculated to a precision of one part in 1012. That's like measuring the distance between the Earth and sun with a precision of a millimeter. Currently, the prediction and measurement do not agree, and this discrepancy might be the first hints of physics beyond the Standard Model, which is our current theory describing the subatomic world.

Why Measuring a Tiny, Spinning Particle Is Such a Big Deal

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