Latest LHC schedule and luminosity for 2008 May 9, 2008Posted by dorigo in news, physics, science.
Here is an excerpt of the latest LHC schedule for the following few months, as agreed in a meeting at CERN chaired by the Director-General, with the experiments and LHC machine heads.
Based on the good progress for the cool down of the LHC sectors, and on the powering tests from two sectors, the following planning was arrived at:
- End of June: The LHC is expected to be cooled down. […]
- Mid of July: The experimental caverns will be closed […]
- End of July: First particles may be injected, and the commissioning with beams and collisions will start.
- It is expected that it will take about 2 months to have first collisions at 10 TeV.
- Energy of the 2008 run: Agreed to be 10 TeV. The machine considers this to be a safe setting to optimize up-time of the machine util the winter shut-down (starting likely around end of November).[…]
- The winter shut-down will then be used to commissioning and train the magnets up to full current, such that the 2009 run will start at the full 14 TeV design energy.
The above means that the machine will deliver collisions from the end of September on, for at most nine weeks in 2008. More safely, one can assume 6 full weeks of data-taking. What luminosity do we expect to collect ?
A state-of-the-art estimate was made by a colleague, who used his past experience with LEP as well as the information on the current limitations of the RF system -which will make the proton bunches shorter than planned (RMS of 5.4 cm), and with a transverse size of 46 microns. At the lower energy the low-beta squeeze will also be loosened from 2 to 3 meters. These figures reduce the instantaneous luminosity, and the estimate for 6 weeks of collisions are of about 40 inverse picobarns of data in 2008.
If ATLAS and CMS will be fully on during the weeks of collisions, these 40 inverse picobarns will fruit, in my opinion:
- A top pair production cross section with 10-15% accuracy
- A sizable sample of vector boson decays to leptons, very useful for calibrations and checks of lepton efficiency studies
- The first estimates of b-tagging and tau-tagging capabilities of current algorithms
- no information on the Higgs
- no SUSY discovery (of course!)
All the above will have a chance of being ready for the 2009 winter conferences, if all goes well…