LHC starting up again

[Alex K]

If I had a clue I'd write a paper. I think missing energy from dark matter of some sort is plausible. A new force carrier maybe, usually dubbed Z'

That's very interesting. The skeptic in me (from a layman's perspective) wonders if it's more likely that there is a fifth fundamental force of nature or that our understanding of the gravitational force is very lacking. I mean, we already wonder why it is so incredibly weak and speculate about it spilling into other dimensions. Plus, we can't unify it with other forces. I wonder if our understanding of it is fundamentally incomplete.

I'm in the fundamentally incomplete camp. Adding one more force carrier similar to the Z boson to the standard model is a relatively trivial undertaking theory-wise, compared to quantizing gravity which is super hard. Even leading string theorists I know think that strings are not the final word.

By the way, strictly speaking we already have a fifth fundamental force, which is produced by the exchange of Higgs bosons. The difference is just that it is produced by a spinless carrier, but it's a perfectly cromulent force...