The discussion centers on the spin of neutrinos and its equivalence to electron spin, specifically addressing the intrinsic property of neutrinos as fermions with half-integer spin (ħ/2). Participants reference the Standard Model, which assumes all leptons, including neutrinos, possess this spin. Experimental evidence, such as the Goldhaber et al. experiment and neutron decay measurements, supports the conservation of angular momentum and confirms the neutrino's spin characteristics. The conversation highlights the implications of neutrino spin on particle decay processes and the theoretical consequences if neutrinos were to possess different spin values.
PREREQUISITESParticle physicists, researchers in quantum mechanics, and students studying the properties of fundamental particles will benefit from this discussion, particularly those interested in neutrino physics and the implications of spin in particle interactions.
I read those (an many more) articles, do they contain experimental data? I must have missed them.I am asking if there is any concrete experimental data that confirms that it has indeed some spin and that its magnitude is h/4pidavenn said:
Thanks , Dave, I was just looking for some experimental evidence, or at least some indirect confirmation. I know the Standard Model assumes all fermions, leptons have spin 1/2. But suppose (ad absurdum) neutrino has no spin, what happens, what is the problem?davenn said:there probably is, but I haven't found any info in my looking
not sure what else you want ?Dave
alba said:.I am asking if there is any concrete experimental data that confirms that it has indeed some spin and that its magnitude is h/4pi
Why can't spin be added during the process?mfb said:A different spin would lead to different angular distributions of the decaying particles, something measured in the experiments of Wu and Goldhaber, and later much more precisely with particle accelerators.
What I meant is that the spin musn't necesseraly be an intrinsic property. Like in a billiard ball any spin can be generated by the cue or by a collision, the value of the spin +1/2 or -1/2 (or any other value) could be determined only by the process. This would also eliminate the akward assumption of an antineutrino antiparticle of itself. Does the linked experiment rule out this possibility? Ihave not the expertise to reach any conclusion.Vanadium 50 said:If the neutrino were spin-0, it would mean angular momentum is not conserved.
If the neutrino were spin-3/2, \frac{B(\pi \rightarrow \mu \nu \overline{\nu})}{B(\pi \rightarrow e \nu \overline{\nu})} would be some number other than the measured ~12,000.
alba said:What I meant is that the spin musn't necesseraly be an intrinsic property.
What do you mean by "added"?alba said:Why can't spin be added during the process?
Assumption of what? It is possible that neutrinos are their own antiparticles, but they don't have to be - measurements are not precise enough yet to distinguish between those possibilities.alba said:This would also eliminate the akward assumption of an antineutrino antiparticle of itself.
mfb said:I think you just want one neutrino in the decay.
alba said:What I meant is that the spin musn't necesseraly be an intrinsic property.
By the way, have you ever seen a billiard ball "spinning" at half-integer angular momentum?alba said:What I meant is that the spin musn't necesseraly be an intrinsic property. Like in a billiard ball any spin can be generated by the cue or by a collision, the value of the spin +1/2 or -1/2 (or any other value) could be determined only by the process. This would also eliminate the akward assumption of an antineutrino antiparticle of itself. Does the linked experiment rule out this possibility? Ihave