I watched this video featuring Michio Kaku explaining parallel universes. In the last two minutes he said that experiments in the LHC could reveal that there might be parallel universes and then he stops. What experiment was he talking about? And how would that be possible?
The LHC is a discovery machine, and a lot of phenomenologists have worked hard to make predictions from various models , some of them using mainstream theories, some of them not.
Searching on the net I found this preprint which proposes checking the data for such signatures:
They have put bounds from their model using available LHC data. Note that they are talking of two parallel universes, not infinite. So the video you watched probably has no connection to this, but I submit it to show how one can search for signatures of the invisible in the LHC data.