Alex, Can you please supply a simple reproducible example? When I set the boost for a term to zero then documents containing it do not come to the top. Nor do they go to the bottom. The boost is multiplied into the weight for the term, but the weights are then added into the document score, so a zero boost will have little effect on the final ranking.
Lucene does not currently support negative boosts, which might achieve what you want. I just made the modifications to required to support negative boosts. Please find these attached and tell me how they work. If they work then I will check them in after the 1.2 release is final. Doug
