Back in 2007, I was writing my diploma thesis (think master's just twice as long, German system prior to bachelor/master) at Auger. The collaboration has a rule that for the first year in, you don't go into the author list, but stay on it for a year after you leave. That optimizes for having the actual contributors on papers. Towards the end of my not-on-the-papers year, the collaboration published a really big paper on correlations between the arrival directions of the highest energy cosmic rays, and certain objects, active galactic nuclei (giant black holes at the center of other galaxies). This didn't just get published in Science, it made it to the cover. It was a step towards working out where these mysterious particles are coming from, and what mechanism might possibly exist to accelerate them to such energies! I was kind of bummed not to have my name on that paper (though even at the time thought the one year rule made sense).

The publication had been hotly debated internally. It had received all conceivable internal scrutiny (the author list contained over four hundred names). There had been a stark debate about what the right statistical significance was for claiming a discovery. Astronomers were used to less rigorous requirements than the particle physicists that together made up the collaboration. Ultimately, it was decided to claim a correlation. (A nil result would have been published as well.)

Almost from the day of publication, the statistical significance of the result, but in data continuously collected since, started to diminish. I was involved in running the nightly data reconstruction, and often times we would huddle around one of the workstations on the morning, to check whether a new high energy event increased or decreased the significance. It kept going the "wrong" way.

The collaboration went into a frenzy to double check everything. They redid the calculations, checked all hardware (a field of water tanks and electronics 3000km^2). Had lots of internal conferences with heated debates.

Ultimately a note was published describing the staggering decline of significance. If I remember correctly, my name was on the author list by then and I got to joke that I knew it all along.

I'm no longer in the field. Since then, the collaboration has published a di-polar asymmetry of the arrival directions of the highest energy cosmic rays. That proves something we already pretty much knew: these are not particles from our galaxy. That was a meaningful discovery. But I'm not aware of a publication with as exuberant a discovery as the source correlation.