What does the spin of a particle tell us ? And what does it means ?
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Feb 23, 2013
The spin of a particle tells us how it behaves under interchange.... Yes, that is true, but what does that mean for physical systems? Things with integer values of spin (0,1,2, etc.) can be in the same place at the same time in the same quantum state. These are called bosons, and a consequence of this is that at low temperatures bosons form condensates where they clump together around the ground state and create Bose-Einstein condensates. Things with half-integer spin (1/2,3/2,5/2,etc.) are called fermions and are a reason why you would still have electrical current even at zero temperature; electrons are fermions and even if they are at zero temperature they cannot be in the same quantum state and so they will always have some distribution of momentum in a metal (see: fermi surface).
There is a lot we could talk about spin, but it also can tell us how a particle decays. Spin is conserved, and so if a particle decays the spin of the products can give limits on the spin of the original object (with restrictions). For instance a spin 0 object can decay into two spin 1/2 objects, but so can a spin 1 object. How do we tell the difference? Well, the decay products will be distributed differently in the detector (eg they will have a different angular distribution) due to the different spins of the mother particles (the particle that decayed).
As a very theoretical side note, spin also has a deep connection to relativity.Feb 27, 2013
+Alexander Anderson-Natale
right!, that sounds to be an well interpretative for more... "What does it means?", "for meaning?" to "tell" approach to some numbers(?) - hihi.Sep 1, 2014