Figure 1: Proof. It happened. (Image: Mine)
This is terrific news and if you happen to see a member of CERN’s accelerator division, be sure to congratulate her or him.
Figure 2: Total (integrated) luminosity delivered to (red) and recorded by (blue) the CMS detector. (Image: CMS)
To give a little context, 1 fb-1 (pronounced: one inverse femtobarn) worth of data is measure of the number proton collisions (scaled by a bunch of physics and efficiency parameters) and is the equivalent of 70 trillion proton-proton collisions. So 5 fb-1 is 350 trillion proton-proton collisions, which is 3.5 × 1014 = 350,000,000,000,000 proton-proton collisions. Before the start of collisions this year, the LHC had only delivered about 35 pb-1 (0.035 fb-1), which is only about 2.45 trillion = 2,450,000,000,000 proton-proton collisions. In other words, 99.3% of the data generated by the LHC came between this past March and Today. How can you not be impressed by that?
Due to detector efficiencies and such, not all the data generated is recorded. The above plot, generated & continuously updated by CERN, shows that ATLAS and CMS have a small bit before reaching 5 fb-1. However, it is very reasonable to suggest that both experiments will have recorded 5 fb-1 before the end of
the third week of November October. (Thanks to Achintya & Dave for catching this mistake. I have “week 43” in my notes for this post, so I have no idea how I ended up with the November date.)
As always, happy colliding.
- richard (@bravelittlemuon)
PS. I refer you to a previous post about what the experiments can do with 5 fb-1.