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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