Outline

1
Status of the Forward Preshower Software

• Jose Lazoflores and Abid Patwa
• DØ Collaboration Meeting
• October 8, 2003

• Outline
• Brief Status of FPS Software
• Current Results
• TMB studies
• Matching Resolutions (CAL-FPS)
• Outstanding Issues and Future Work
• Closing Remarks

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Summary of FPS Software

• Overview of FPS reconstruction
• combine adjacent strips in u-v sublayers of each
  wedge
• locally match u-v pairs
• convert u-v matches in global (?, ?)
• non-trivial/tricky FPS spherical geometry
  (perfect sphere assumed)
• cut on energy correlation (optional)
• run fps_reco ? fps_analyze to generate flat-file
  with MIP calibration (in groups of 8
  FPS-channels)
• see A. Patwas March 28, 2003 ADM talk for
  discussion of calibration algorithm
• flat-file available in d0_reco
• Tremendous effort in understanding and testing
  fps code with data and resolving software bugs
• fps offline software had originally been written
  and tested on MC
• required modifications in order to be adapted for
  data
• General comments
• due to several fixes, reprocessed data based on
  p13 DSTs will not have good FPS information
• pre-Moriond (pre-Jan 2003 shutdown) data has 9
  out of 64 FPS wedges with some degree of mapping
  errors
• errors related to FPS hardware in particular
  waveguide installation and a few channels (16) in
  Shower layer on a series of AFE boards
• fixed AFE problems before Jan 03 shutdown
• fixed waveguide map problems during Jan 03
  shutdown
• post-Jan 03 shutdown data, post-run 172354
  should be used to commission FPS software

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Summary of FPS Software (cont.)

• Brief history of releases and FPS
• p13.06.00 major fix to incorporate post-Jan 2003
  shutdown map
• p14.01.00 minor mapping and bug fixes and
  updates...
• p14.02.00 first production version of FPS
  software
• FPS data in DST/TMB is now useful for first-pass
  physics analyses
• new versions with bug fixes of fps_analyze,
  fps_unpdata, and fps_address
• fps_geometry, fps_event are tuned for real data
  with reduced chunk size
• offline thresholds (still not optimized) are
  adjusted in fps_reco to reduce DST size
• p14.03.00 improved FPS reconstruction
• fps_address, fps_reco initializing variables bug
  fix
• p14.03.01 currently on farms
• fps_address, fps_reco, fps_unpdata fix phi bug
  and incorporate u-v layer flip
• p14.04.00 improved, more accurate FPS maps and
  geometry
• updated fps_geometry to include global ?-rotation
  of 0.019 radians (for both FPS-N and FPS-S) ? fix
  detector alignment in ?
• TMBTree information updated with new MIP
  calibration
• unpacker fps_unpdata fixed minor mapping
  problems
• We (Patwa) believes FPS mapping issues not
  completely resolved complicated mapping
  convention used

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FPS ? alignment (using FPS-TRK)
Rotate FPS ccw
Rotate FPS cw

• Using Z?ee sample, observe FPS-TRK d? resolution
• Systematic shift in ? averaging 19 mrad seen
  for both FPS-N and FPS-S ? corrected in p14.04

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Preshower Commissioning
Observation of MIPs Forward Preshower
E(MIPs)
E(MIPs)
E(MIPs)

• Commissioning of software continues...
• run on raw data processed with fps_analyze
• observation of MIP peaks with collider data
• Tag mips in FPS MIP u ? v sub-layer (Nstrip, E)
• examine energy of matched cluster in other MIP
  layer
• clear evidence for singlet and doublet peaks
• for more than 2 strips, energy consistent with
  the passage of 2 particles

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FPS y vs. x Distributions

• FPS y vs. x distributions
• observe u-v clusters per Shower, MIP layer
  useful for monitoring global mapping errors or
  dead channels
• Also, look at mip coincidences in wedge-to-wedge
  overlap region
• 5.3 of ? has overlapping wedges (i.e., 0.5 per
  wedge ?-side)
• may help relate problems in (? ? ?)?

8
TMBs for FPS

• Main effort during past weeks in developing
  TMBTree for FPS
• Additions of new variables and tools in
  TMBFpsMaker.cpp .hpp and TMBFps.cpp .hpp (p14.04)
• list of variables, definitions
• r -gt FPS hit radius
• z -gt FPS hit z position
• phi -gt FPS hit phi position
• E -gt Integrated cluster energy
• cntrd_u -gt Centroid strip in u
• cntrd_v -gt Centroid strip in v
• nstrp_u -gt Number of strips per hit in u
• nstrp_v -gt Number of strips per hit in v
• index_cl -gt Indexing of FPS wedges in each layer
• rms_u -gt Cluster root mean square per hit in u
• rms_v -gt Cluster root mean square per hit in v
• ecl_u -gt Cluster energy in u
• ecl_u -gt Cluster energy in v
• M. Lynker studied FPS-TRK matching resolutions
  with DSTs (using wz_analyze)
• Present study concentrates on FPS-CAL resolutions
  (in ?, ?, r)
• with TMBs

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CAL-FPS Matching Resolutions ?
CAL-FPS (N-MIP, N-SHW, S-MIP, S-SHW) d?
Distributions

• Core resolution to first-order appear okay
• centered about d? 0.0
• but, significant contribution of shoulders and
  tails
• Mapping issues in 3 FPS wedges still existing on
  South-MIP layer and 2 FPS wedges in South-Shower
  layer
• Shoulders/tails also partially due to MIP
  calibration for FPS, which is known to about 20

10
CAL-FPS Matching Resolutions ?
CAL-FPS (N-MIP, N-SHW, S-MIP, S-SHW) d?
Distributions

• Recall, p14.04 fps_geometry contains global ?
  rotation fix of 19 mrads
• needed to resolve alignment issues
• current TMBs run on Z?ee sample processed through
  localbuild of p14.03 and thus, with alignment
  fixes
• Distributions centered about d? 0.0 mrad but
  appear broad
• just for reference observed FPS-TRK d? 3.6
  mrad (integrated over wedges in FPS-S Shower
  layer)
• width on the order of size of one FPS wedge
  (22.5o 0.392 radians
• Again, correlated with known mapping issues in
  FPS wedges
• Investigations continue...

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CAL-FPS Resolutions d? vs. Wedge
CAL-FPS (N-MIP, N-SHW, S-MIP, S-SHW) d? vs
FPS-Wedge Distributions

• Define all 64 FPS wedge indices by side and layer
  
• zlt0, FPS-N Shower 1-16
• zlt0, FPS-N MIP 17-32
• zgt0, FPS-S Shower 64-79
• zgt0, FPS-S MIP 80-96
• Effort to understand wedge-by-wedge mapping
  effects
• from studies, isolated on FPS-South 3 wedges in
  MIP layer, 2 wedges in Shower layer

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Matching Resolutions dr rcal (_at_zfps) - rfps
CAL-FPS (N-MIP, N-SHW, S-MIP, S-SHW) dr
Distributions

• Look at dr, defined by r_cal r_fps, where r_cal
  is radius of calorimeter cluster re-computed at
  z_fps
• Used to understand d? resolutions and monitor
  mapping errors
• Consistent with observations in d?, d? resolutions

13
Outstanding Issues and Closing Remarks

• FPS has come a long way in the past year and
  commissioning is progressing...
• primary focus thus far in improving matching
  resolutions more work still needed
• mapping issues still needs to be fully resolved
• detector efficiencies still needs to be studied
• L1/L2 Trigger work with FPS has begun
• FPS SVX-gains have stayed same since start of
  detector commissioning proposal is to
• keep MIP-layer gains as is
• lower Shower-layer gains by factor of ?2 after
  10-week shutdown ? setting where CPS presently
  stands
• Reco-level modify the method by which FPS-TRK
  cluster matching is done
• Tracks extrapolate to a z such that for each FPS
  cluster within some loose d? window, re-compute
  the track position at true FPS z position
• Clusters using a PV, extrapolate back from the
  CAL z position to FPS position apply possible
  cuts on dr and d?
• Currently, little focus on using FPS MIP-layer
  for forward tracking
• DØ Note with overview of FPS software and
  definitions in TMBTree due out soon...
• Feedback from id-groups and physics analyses
  needed to continue understanding response from
  the detector