Dumping Data Overboard: The Trigger at an LHC Experiment

Did you know that most of the information produced in the proton-proton collisions at the Large Hadron Collider (LHC) is dumped irretrievably in the metaphorical trash bin — sent ingloriously into oblivion — yes, discarded permanently — as quickly as it comes in? By “most,” I don’t mean 75%. I don’t mean 95%. I mean 99.999% to 99.9999% of all the data at the Large Hadron Collider is erased within a second of its being collected.

It sounds crazy; how can a scientific experiment simply ignore the vast majority of its data?! Well, it’s not as insane as if first appears. Nor is it unprecedented; previous generations of hadron colliders have done something similar. And finally, it is absolutely necessary. In this article I’ll tell you why.