Fifth force?

[Zefram]

I was reading this article (http://www.npl.washington.edu/AV/altvw15.html) by John Cramer (those are usually pretty out there) and I noticed that the references (and probably the article itself) are from the '80s. I then found that this stuff is mentioned in the World of Physics (http://scienceworld.wolfram.com/physics/FifthForce.html). So what's the state of this idea today? Any possible connection to the accelerating expansion of the universe? Or any other interesting tidbits?

[selfAdjoint]

They looked for that fifth force for a long time. You used to see pictures in mags like Science News showing people with instruments by some cliff, trying to detect it. They never did, and it sank out of the radar. I don't know what ever happened about the curious velocity-dependent behavior of Kaons.