All dressed and ready to go

In a few days, the four large experiments operating at the Large Hadron Collider (LHC), the 27-km long accelerator from CERN, will be ready to collect data again. The accelerator is just about to resume normal operation after the four-month annual shutdown needed for regular maintenance. A long commissioning process, started at the beginning of May, should be completed any day now. The LHC operators had to slowly and safely bring back the accelerator complex into operation, testing all components along the way. Once back into full operation, it should produce enough collisions to allow the experiments to double their data sample. Collecting more data is the best way there is to refine all measurements made so far and hopefully also discover new particles or phenomena.

During the shutdown, the experiments took the opportunity to repair faulty equipment and implement various improvements. Once the accelerator started delivering test beams, the physicists had to make sure that the whole detector and all the components making up the data acquisition system worked properly and harmoniously. This tedious process is now completed. With the size of the experiments nowadays at CERN, this took place over several weeks to bring all detector sub-systems and various components of the complex data acquisition chain back into action.

Back in 1990, when I was a graduate student on a small experiment called E791 taking place at Fermilab near Chicago, it only lasted a few hours and was called a “dress rehearsal”. Being a non-native English speaker, I had no clue what that expression meant. I asked the woman in charge of it what would I have to do. She simply replied: « Just stand there and look pretty ». So I decided to take it literally and convinced two other graduate students, Penny Kasper and Danying Yi to join in. Just before the dress rehearsal, we sneaked out of the control room to come back dressed to the nines. Penny wore her best dress, Danying put on the dress her mother had sent from China, hoping to encourage her to get married and I wore my mother’s spiffy copper satin wedding dress. When we showed up in the control room, our colleagues looked puzzled, to say the least. Most had a good laugh, even though I suspect many of them just thought we were plain nuts.

Huge doses of humor and patience will be necessary to tackle the huge task that might lead to new discoveries. Since nothing easy to find jumped to our eyes in last year data, we are probably in for a long haul. All physicists know there is way more to be discovered but no one knows when we might luck out. But if we do, I’ll make sure to get my good dress out again.

Pauline Gagnon

To find out more about particle physics and what’s going on at CERN, check out my book « Who Cares about Particle Physics: making sense of the Higgs boson, the Large Hadron Collider and CERN ».

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