Wow, what a terrible trip to CERN I’ve been having. I’m here for the semi-annual CMS computing and offline software workshop week, but I took ill while here and have been confined to my room in the hostel for the past two days. That and my jet lag have totally put me off my game. I am definitely on the mend now and expect to be out and about today, and that will be a great relief. Thanks to all of our modern devices, I could keep up with what was going on in official meetings from my room, but I could have done that from my office in Lincoln too — the point of coming here is to see my friends and colleagues face to face and for us all to talk about what is really going on and what we should be doing about it. You don’t always learn that from the talks in the meetings; it’s all about the hallway conversations and the extended lunches (and those long periods of watching other people drink coffee that I’ve written about before).
But what I can see, even from inside, is the growing level of intensity as it becomes clear that the LHC restart is upon us. Seth of course mentioned earlier this week that particles were injected into the LHC over this past weekend, for the first time since last September. He didn’t mention that it wasn’t just protons injected, but also lead ions, and I think this was the first-ever injection of heavier nuclei into the LHC. With that done, fully circulating beam (making a complete circuit of the machine) could come as soon as next weekend, and that means that the detectors must be totally operational now. Even with only one proton beam (not colliding with another beam) there is a lot to learn, as we saw last year — you can see particles from the “beam halo” streaming through the detector, and also “beam splash” events. All indications are that we will have some kind of collisions, although probably at relatively low energies, before the Christmas shutdown. Then the pressure will be on the experiments (not the accelerator!) to quickly turn around and show that they can do something sensible even with the small number of collisions that we will probably get at first. Well, this is what we’ve spent twenty years preparing for — we must be ready.
It’s hard to believe that it’s really happening. Let’s hope it seems as real after I finally get home, tomorrow night, and get some proper sleep.
