Anatomy of an “Anomaly”

by landonlehman

On Tuesday, December 15 of last year, the LHC experimental collaborations ATLAS and CMS released the first results from the 13 TeV run. The most exciting news was a bump in the diphoton spectrum at about 750 GeV. This could be a sign of new physics (finally), or it might just be a fluctuation (the statistical significance is not very high). We will probably have to wait until at least late summer to find out whether or not the bump disappears with more statistics (this an optimistic estimate as far as magnet issues go).

Of course this “anomaly” is exciting and gives theorists something to think about. But I want to focus on the amount of thinking that has been done already, measured in part by the papers that have been written. (Of course, one could argue that the number of papers written is not a good proxy variable for the amount of real, hard thinking that has been done. One might have a point.)

Seven papers citing the ATLAS or CMS papers were submitted on the day of the announcement (i.e. the same day the ATLAS and CMS papers were released). Obviously a good number of theorists had advance warning. Here is a plot of the number of papers versus the date of their arXiv submissions from Dec. 15 until today (not counting the papers that just showed up on the arXiv tonight).


The vertical orange lines are for Mondays, the day when diphoton papers were most likely to be submitted. There is an idea that your paper is most likely to be read if you submit in on a Monday (so it shows up on the arXiv on Tuesday). So far there have been 172 papers!

For those interested in how I made the plot, I used inspire and searched for papers citing either the ATLAS results or the CMS results, and sorted by the earliest date recorded (“de”). I didn’t use both/and, because sometimes it takes a while for inspire to correctly catch all of the citations.