Is there something that is not affected by gravity?

[Polaris]

Is this graviton predicted in the standard model?

No, it doesn't say anything about gravitons.

But beyond the stadard model, there has been a strong suspicion since Einstein that gravity at a deep level is symmetrical with the three forces covered by the standard model. So by analogy with those other three forces, gravity would be expected to also be carried by its own messenger particle, the graviton. Although standard model doesn't predict a graviton, particles fitting the necessary characteristics of gravitons doesn't conflict with the standard model.

So at this point existence of the graviton is a well educated guess, but not a strongly supported fact. The gravitational wave experiments planned can potentially verify the existence of gravitons.

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That's like saying a feather affects the wind and is responsible for the wind because it is showing wind exists.

No, it's not. It's like saying you can't change the flow of the air with a feather if the feather doesn't interact with the air. Dark energy won't come out as a residual terms in einstein's equations if it didn't interact with gravity.

Dark energy is theorized as the driving force of gravity (as you cannot have an effect without actual mass)...gravity is one of the proofs dark energy exists under that theory.