A new Muon misalignment scenario for 2011 (7 TeV) Monte Carlo re-processing was re-leased. The scenario is based on running of standard track-based reference-target algorithm (exactly as in data) using single-muon simulated sample (with the transverse-momentum spectrum matching data). It used statistics similar to what was used for alignment with 2011 data, starting from an initially misaligned Muon geometry from uncertainties of hardware measurements and using the latest Tracker misalignment geometry. Validation of the scenario (with muons from Z decay and high-pT simulated muons) shows that it describes data well. The study of systematic uncertainties (dominant by now due to huge amount of data collected by CMS and used for muon alignment) is finalised. Realistic alignment position errors are being obtained from the estimated uncertainties and are expected to improve the muon reconstruction performance.

Concerning the Hardware Alignment System, the upgrade of the Barrel Alignment is in progress. By now, data taking for calibration of all the MABs and the MiniMABs is finished. MiniMABs are installed on YB0, YB–1 and YB–2. Patch cables for the BoardPC repositioning are installed on YB0, YB–1, YB–2 and YB+2.

by M. Dallavalle