Quantum gravity force violations

[touqra]

Apart from C, P and T violation in weak interaction, do the same violations occur for the other three forces, in particular, the quantum gravity force?

 

[zefram_c]

Both EM and strong force respect C, P and T. I am pretty certain that gravity also respects them: a particle has the same mass as its antiparticle so its gravitational pull is the same (C). I think Einstein's equations are time reversal invariant so (T) holds, hence (P) should also hold by CPT.

 

[touqra]

Both EM and strong force respect C, P and T. I am pretty certain that gravity also respects them: a particle has the same mass as its antiparticle so its gravitational pull is the same (C). I think Einstein's equations are time reversal invariant so (T) holds, hence (P) should also hold by CPT.

Why then is the weak force the only force to violate C, P and T symmetry? Isn't that funny?

 

[Haelfix]

The answer is that experiment demands it..

So by construction the theory is chiral, eg its a gauge theory in the yangmills sense with two representations of SU(2)

Su(2) (left) * Su(2) (right)

 

[selfAdjoint]

So by construction the theory is chiral, eg its a gauge theory in the yangmills sense with two representations of SU(2)

Su(2) (left) * Su(2) (right)

And that is because SU(4) the double cover of the Poincare group, just happens to decompose into two copies of SU(2), so the 4-component spinors have their first two components acted on independently of their last two. Left and right helicity.