[SomewhatLikely]

Both of your references use RRF=1/(60+Rank)

So I'm not sure why the article uses 1/Rank alone. Did you test both and find that the smoothing didn't help? My understanding is that it has been pretty important for the best results.

[johnjwang]

It's a good call out -- we use smoothing parameters that are closer to what you see in the academic articles (they're tuned slightly, but not much).

We used 1/Rank in the article for simplicity purposes, though I can see why this might be confusing to an astute reader.