Does panpsychism state that the mind exists in a different dimension? They seem to allude to the existence of a soul, and that the mind is a part of the fabric of reality, but are they saying that the mind exists in a different dimension? Because they seem to be saying that the brain isn't the only thing that produces the human consciousness.
I would not use the word 'dimension'. The problem with this word in this context is that it is used in a very precise mathematical way by physicists, and in this mathematical sense it would certainly not be the claim of sophisticated contemporary panpsychists that mind exists in a different dimension.
The clearest contemporary panpsychist statement that I am aware of is the line of Philip Goff and others, which draws from Bertrand Russell's suggestion that physics studies extrinsic structural relations of the world and its constituents, and that conscious experience seems in the case of ourselves (the only thing we know from the inside, as it were) to be our intrinsic nature, so maybe it is the intrinsic nature of everything else too. But it will never be found by physicists in some hidden dimension or whatever, because the whole methodological point of physics is to exclude this approach.