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Name: David S.
Status: student
Age: 16
Location: N/A
Country: N/A
Date: 4/26/2004


Question:
Is there anyway to measure the spin of a particle mathematically? Or can this be achieved using a hypothetical particle?


Replies:
I am not sure what you mean by "mathematically" or "a hypothetical particle", but the Dirac equation, first written by Paul Adrien Maurice Dirac predicted that the electron would have a spin of 1/2. That means an angular momentum of 1/2 times Planck's constant divided by 2*pi. It also predicted the existence of the antiparticle of the electron, called the positron, which was soon discovered.

The electron and the positron are real particles, and numerous experiments prove conclusively that they have spin 1/2. These are real measurements, not using hypothetical particles. I participated in measuring the spin of the lambda hyperon -- it has spin 1/2 also. The spin of numerous other particles have also been measured.

Best, Dick Plano, Professor of Physics emeritus, Rutgers University



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