This was a thing last year:

Band creates the 'most relaxing tune ever' - Telegraph

Kinda funny little study. I checked out all the songs that were considered and most of them I would consider to be upbeat, but I gotta admit the winner was a heavyweight. Marconi Union. I listened to quite a few more of their tracks and I really dig them now as an ambient group.

Marconi Union - Weightless - YouTube

It reminded me of this:

Portal Soundtrack - Self Esteem Fund - YouTube