CMS m Alignment Status and Goals for 2011

1. CMS m Alignment Status and Goals for 2011 MU Barrel Workshop

2. 2011 Alignment Goals Understand systematic differences between HW / TB barrel alignment Provide realistic APEs Alignment of barrel (+ endcap?) using Stand-Alone muons Complete/update endcap HW alignment: SLMs + TLs Merge HW and TB alignment information in endcaps+ barrel Study of MB1-ME12 overlapping tracks checkrelative YE-YB alignment Several others regarding technical issues Optimization, automation, merging of HW system DAQs etc MU Barrel Workshop

3. Status shown by POG during Physics Week Muon Alignment: current status Barrel alignment comparison (exaggerated by a factor of 200) • Two alignments for comparison: track-based and hardware • They agree on the mm-scale positions of chambers, but differ by a “twist” of 2 mm amplitude: sin(phi) x eta bias in track pT for TeV-scale muons (~0.2 c/TeV) • Resolving this is our highest priority (several ongoing studies) • Current geometry from hardware • Endcap aligned using a combination of hardware, beam-halo, and collisions tracks • Beginning new project to supply APEs (misalignment-dependent weights for track-fits) to improve TeV-scale track-fitting Sample plot from endcap alignment before alignment after alignment MU Barrel Workshop

4. Status shown by POG during Physics Week Muon Alignment: projections and plans Projections: Plans: • pT > 15 vs 20 GeV/c → 30% effect • Best track-based resolution for first-station chambers • Reaches systematic limit at ~1 fb-1 • Systematic issues (e.g. “twist”) do not scale with integrated lumi • Continue working with comparisons of TB collisions, cosmics/BH, and HW This is very conservative: 0T vs PG indicate ~500 mm Note: barrel ali with collision muons ongoing MU Barrel Workshop

5. Link Disk (-) readjustment • Soon after the detector closing in January 2010, the negative Link Disk structure (LD-) suffered an impact. • This impact rotated the LD- around Φy ~-3 mradand around Φx~+1 mrad. • As a consequence of the LD incident, some laser hits were lost: After incident. No Signal. *: 2 sensors at B=0T; only 1 at B=3.8T. In January 2011, the Link team performed a reorientation of the LD-, in order to recover laser impacts. MU Barrel Workshop After reorientation. Good Signal.

6. LD- readjustment: -z recovered! LD- reconstruction (inside YE-1) using laser impacts in 3 different periods all at B=0T. Note: we purposely remove inclinometer data from fit for independent cross-check purposes(not our standard reco) DATA INFO • Jan-10: First data after closing in January 2010 before field. Immediately after, the LD- was displaced physically (LD incident). • Oct10: Data at B=0T after several magnetic cycles and after LD- incident. • Jan11: Data after reorientation of LD- by Link Team at B=0T. • Since 10-February, full field back again: B=3.8T • After ramp to 3.8 T, still 4 out of 6 AR- lasers reach YE-1 !! (see Zoltan’s talk) MU Barrel Workshop

7. Barrel + Link HW Alignment @ 3.8 T •  New barrel alignment at 3.8 T • See Zoltan’s talk • New link alignment at 3.8 T • Benefits from recovered negative side • Both use recent 3.8 T data taken simultaneously (on Feb. 13, 2011) • These alignments are very new (from this week) and are therefore still preliminary MU Barrel Workshop

8. TB-HW “Twist” • Systematic difference between HW and TB barrel alignments • Overall 4-5 mm end-to-end effect in z and rf • Dominant source of alignment uncertainty! Priority: highest People: ALL Timescale: unknown MU Barrel Workshop

9. “Twist-free” Track-based Muon Alignment Aysen Tatarinov, Texas A&M • 2010 – a relative "twist" is observed in the barrel in track-based muon alignment with respect to hardware muon alignment. • Feb 2011 – a new "twist free" tracker alignment produced by Tracker DPG • 20 Feb 2011 – the twist is gone with latest track-based muon alignment with the “no twist” tracker. Muon pT =15 – 200 GeV, multiple refit of global muons. HW vsTBnewTK NO “TWIST” HW vsTBoldTK “TWIST” (animated slide) MU Barrel Workshop

10. “Twist-free” Track-based Muon Alignment Aysen Tatarinov, Texas A&M 2D view of station 1 HW vsTBnewTK NO “TWIST” HW vsTBoldTK “TWIST” • Summary • The “twist” is gone with the latest tracker alignment • The agreement with the hardware based alignment has substantially improved • Although some more polishing to be done before producing a new quality alignment • It is clear now that comparisons of track-based and hardware muon alignments is a good tool for detecting possible tracker deformations • A valuable feedback and a cross-check for the tracker people Detailed discussion at tomorrow’s mali: stay tuned! MU BarrelWorkshop

11. APEs • POG asks for realistic APEs (for DTF) • For each d.o.f. of each chamber • For TB: from covariance matrix • For HW: under study Priority: high Timescale: 1 month • Work is ongoing • For HW: take at zeroth order residuals from PG comparison at 0T (subtracting PG uncertainty) (different APEs for different DTs, for example station 4, special DTs not well reconstructed, DTs close to lost MAB, etc etc) • Collective wheel movement factored out • Global z uncertainty has a “constant” term and a linear term which scales with |z| because this uncertainty is cumulative for HW alignment • For all chambers: GlobalPosRcd should include APEs as well: this way there is no need to convolute muon alignment APEs with errors in the TK-MU relative positioning MU Barrel Workshop

12. Alignment using SA Muons Priority: medium Timescale: 3-6 months • Important test, independent from tracker • See status talk by Luca today (24-Feb-2011) • Some comments • Manpower not great: only one person • After/If barrel alignment is successful, no reason not to extend it to endcap (endcap is harder with cosmics, and few high energy collision muons so far…) • It would be desirable to find one more person to work on extension to endcap when/if the time comes MU Barrel Workshop

13. Endcap HW Alignment Priority: medium Timescale: unknown • We need to update SLM alignment • We must finish transfer line analysis • Merge SLM+TL+Link into one endcap HW ali • Some comments • Manpower concern: • SLMs have only ½ FTE • TLs have only ¼ FTE • Who will do this in the longer term? Are the responsible institutions going to ensure a proper transfer of knowledge and tasks? • What are realistic timescales in the short term for these tasks? MU Barrel Workshop

14. Merge TB and HW alignment info • Current barrel situation: • two separate alignments now agree • reasonably well (to be quantified, • detailed discussions will start tomorrow). • We can now start thinking about combining • to get the best of each • Current endcap situation: • attempts to unify HW and TB are ongoing Priority: medium Timescale: 6 months? MU Barrel Workshop

15. MB1-ME12 overlapping tracks Priority: medium People: ?? Timescale: 2-3 months? • Look at tracks overlapping MB1 and ME12 • chambers • Extrapolate MB1 track into ME12, check out residuals • Powerful to determine MB – ME relative positions • Use TB-aligned barrel and endcap • Use DTs and CSCs anchored to Link MABs on one single side • Some comments • This task does not yet have a person assigned to it MU Barrel Workshop

16. MU-TK cross-alignment • Determine the MU position with respect to TK using global tracks • New MU-TK cross alignment will be presented tomorrow at mali meeting by Alexander Spiridonov • Barrel+Link will soon provide new alignment • X-alignment should find small corrections to barrel position if the barrel is anchored to link MABs • Because Link MABs are referenced to Ars which are placed at PG and TK GPR is also taken from PG •  Input: • New internal “twist-free”tracker alignment • Current (not 2011 yet!) internal optical barrel alignment • 70K global tracks • TK GPR: • Was using x,y,z from PG = (-0.09, -0.11, -0.17) cm, but all rotations were 0 • Now includes non-zero rotations: • Rz from PG (large, -1.2 mrad) and Rx (300 mrad) from B-field vs TK axis studies • This should in turn make the MU GPR rotations (especially Rz) smaller • Output: • Global Position Record for Muon System MU Barrel Workshop

17. Summary • Recovered link functionality on –z side after shutdown intervention: link is better than ever at 3.8 T • Also additional improvements such as including inclinometer information • New (preliminary) link+barrel HW alignment for 2011 at 3.8 T • Barrel HW-TB twist, our topmost priority, seems to have been solved • Much improved agreement between the two methods • Opens up a few more lines of work such as • merging of HW and TB in barrel • Using HW-TB differences to constrain TK alignment • Aside: maybe a few changes to current alignment section of performance paper (this is why I asked for a 4-day extension) • Realistic calculation of APEs for barrel (HW and TB) and endcap (TB) is ongoing • Barrel alignment with collision muons is ongoing • Expected performance as a function of ∫Ldt known • Barrel alignment using SA muons is progressing well • MU-TK cross alignment procedure well established (and fast) • Merging of HW endcap alignment with TB endcap alignment is ongoing We are in better shape than ever MU BarrelWorkshop