**Spin Inversion Symmetry - Predicting the Graviton**

SIS (Spin Inversion Symmetry) is a conjecture, it says: Every elementary particle in the Standard Model (except the Higgs) of spin s has a partner of spin 1/s.

So the fermions (spin 1/2) in the Standard Model would have spin 2 partners and the bosons (spin 1) in the Standard Model would be their own partner.

Of course, for this to work we need to have at least one spin 2 particle. Maybe more. So gravity appears automatically.

Content written and posted by Ken Abbott abbottsystems@gmail.com