| CMS Note | |
| Report number | CMS-CR-2012-134 |
| Title | The CMS Tracker alignment in p-p collisions |
| Author(s) | Bhardwaj, Ashutosh (Delhi U.) ; Ranjan, Kirti (Delhi U.) |
| Publication | 2012 |
| Collaboration | CMS Collaboration |
| Imprint | 09 Jun 2012 |
| Number of pages | 3 |
| Presented at | 12th Pisa Meeting on Advanced Detectors: Frontier Detector for Frontier Physics, La Biodola, Isola d'Elba, Italy, 20 - 26 May 2012 |
| Subject category | Detectors and Experimental Techniques |
| Accelerator/Facility, Experiment | CERN LHC ; CMS |
| Abstract | The CMS all-silicon tracker consists of 16588 modules. Aligning these with the desired precision of a few micrometers is only feasible using track based alignment procedures. Ultimate local precision is now achieved by the determination of sensor curvatures. This leads to about 200 000 parameters to be calculated simultaneously. The Millepede II program interfaced with CMS software is optimized to provide solution in one step. The main remaining challenges are systematic distortions in the achieved geometry that are systematically biasing the track parameters like the track momenta. These distortions are controlled by adding further information into the alignment workflow, e.g. the mass of decaying resonances. In addition, the orientation of the tracker with respect to the magnetic field of CMS is determined with a stand-alone chi-square minimization procedure. The geometries are finally carefully validated. The monitored quantities include the basic track quantities for tracks from both collisions and cosmic muons and physics observables like resonance masses. |
| Copyright/License | Preprint: (License: CC-BY-4.0) |
记录创建於2012-07-20，最後更新在2018-06-07
