The 3-sigma that you're quoting may not account for the "look elsewhere" effect: the possibility that a comparable fluctuation might have occurred in any number

The 3-sigma that you're quoting may not account for the "look elsewhere" effect: the possibility that a comparable fluctuation might have occurred in any number of other energy levels or other decay channels. It's really hard to correct for that properly, and particle theory has a long history of promising signals melting away with more data. That's why the folks involved are being pretty cautious. Meanwhile, I'm not sure how well the observed decay mode fits with the most common supersymmetric models: I have the strong impression that it's not one that SUSY phenomenologists were expecting going in. It's going to be fun to see where this takes us! Maybe a surprise would be the best outcome of all.