- #1

Neitrino

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I am a little bit confused could you pls help me ...

Suppose I a have a scatering or conversion of two particles via graviton propagator.

Graviton propagator couples with energy-momentum tensor of matter fields.

So can i assume that vertex to which graviton propagator is coupled is in fact energy-momentum tensor ?

Energy-momentum tensor is conserved and thus if i take graviton propagator in some general case where i have graviton momentum in numerator it should give me vanishing contribution.

But energy-momentum tensor (which I cast in this case as a vertxe +external lines) contains two different momentum: ingoing momentum p1 and ingoing momentum p2, so my propagator momentum will be q=p1+p2... so does it mean that when I express graviton momentum through p1+p2 and and couple it to a vertxe i will have identical zero...?

Thanks