### SPIN & PARITY STATISTICS

**SPIN v PARITY**

The top chart shows the number of isotopes with odd and even parity against those with integral or half-integral spin. There are many more isotopes with even parity and integral spin (this includes spin-0 bosons) than there are with integral spin and odd parity. This must mean something. I wonder what?
**PARITY**

The parity of an isotope can be either even (+) (fawn coloured bar) or odd (-) (blue coloured bar). There are more than twice as many isotopes with even parity than there are with odd parity. Quite what the significance this has, I haven't a clue!

Parity is conserved except in weak interactions (e.g. beta decay processes)

**SPIN**

By definition, all bosons have integer spin (green coloured bars). Similarly, all fermions have half-integer spin (red coloured bars). Taking all the known isotopes together, there are nearly the same numbers of bosons as fermions.

**BOSONIC**

All isotopes with zero spin (spin-0) have an even number of protons and an even number of neutrons (even-N, even-Z), thus are composed of a whole number of helium-4 nuclei. As can be seen, most bosons have zero spin, and the higher the spin, the fewer bosonic isotopes.

**FERMIONIC**

This contrasts with the fermions. The peak spin number for the fermions occurs at spin-2½. Quite what the significance this has, I haven't a clue!