# Presentation: 203496

## South Arm: Hardware and Analysis Status

- Brief overview of muon arm
- Physics goals-->implied performance requirements
- Status of system and hardware performance
- Analysis plans
- Status of software and analysis

## PHENIX Experiment

- MVD - multiplicity and vertex
- Beam-Beam - trigger, time
- Central Arms:
- |y| < .35 (±20o),   = 180o
- high occupancy
- excellent p resolution
- PID covering wide p range and  particle types
- Detect e, , , K
**Muon Arms:**
- 1.2 < |y| < 2.4,   = 360o
- lower particle multiplicity
- higher geom. acceptance
- Detect single and di-muons
- complimentary to Central arm measurements

- Goals:  Search for multiple signatures of the QGP
-              Measure spin contributions from gluons and anti-quarks, through multiple
-                   channels
-              Study p-nucleus interactions

## Physics Goals of Muon Subsystem

- Contribute to systematic study of expected QGP signatures:
_**Debye screening**_ --> varying suppression of vector mesons (J/, ’, )
- _Strangeness production_ --> enhancement of other?
_**Charm production**_ -->cross section measurement, understanding required for background subtraction (from single s or e- coincidence)
- p-Nucleus experiments:
- study of nuclear effects (shadowing, energy loss, etc.)
- p-p: spin structure of the nucleon

## PHENIX Muon System Overview

- LANL responsible for “South” muon tracker system (mechanics, electronics, oversight); North mechanics and help with installation
- Muon Tracker specifications
- 3 stations of cathode-strip chambers
- 6,6,4 readout planes per station
- 100 m resolution per plane
- various stereo angles
- Noise 2 adc counts on strips
- Good track finding in Central Au-Au events

## South Arm: Hardware Status

- South arm installation “complete” early 2001 with electronics fully functional and a few HV channels not working
- No data until summer 2001
- Lost access to inside of magnet in spring
- Lost 8/168 FEMs entirely, few more with data problems==> much larger fraction of **dimuon **acceptances loss (~40%).  But stable since spring of 2001
- High humidity of summer uncovered HV sensitivity to humidity.  Many channels disabled.  Also found:  various mapping problems, some channels which don’t work even with low humidity
**SHUTDOWN PLAN**:
-  Fix electronics (pull off station 1)
- fortify chambers against humidity
- Add shielding to station 2
- Change station 1 HV distribution

## South Arm: Hardware Workers

**People available for south installation:**
- Full-time at BNL
-   3 post-docs (Rusty, Ming, Dave B.), one experienced grad student (Andrew), 3 or 4 additional students, one dedicated tech
- Significant fraction at BNL:
-   Melynda, Dick, Dave, Walt, Mike, Peter
-   2 from UNM (Nicki and Doug)
-   1 from NMSU (Steve)
-   2 from RIKEN (Jiro and Yuki)
**Available for North:**
-   2 fewer post-docs (none with FEE experience)
-   no experienced grad students
-   similar number of other students and techs
- Significant fraction:
-   2 fewer staff from LANL.  Same fraction from rest of staff?
-   1 from UNM not available until summer
-   Added:  French team, others?

**TO DO:**  North installation + south repair + finish North chamber bulding

## South Arm: Analysis and Performance Status

**Physics from Year-1:**
- Low luminosity, smaller integrated run time, plus detector inefficiencies left us with rather small data set for analysis (few hundred J/psis in both Au-Au and p-p runs; probably similar numbers of single muons at high pT)
**Analysis of Year-1 data:**
- What performance is required to extract physics?
- Data extraction working in PHENIX environment - DONE
- Reasonable electronics noise levels - DONE
- Calibrations working, at required precision - pretty much DONE
- Hit clusters found in Au-Au as well as p-p environment - DONE?
- Hit position extraction from clusters working - DONE to first order
- Track finding working well - code in place.  Undoubtedly some tuning required
- Track reconstruction works well - seems to work reasonably well with Monte Carlo
- Alignment of tracker and tracker to other systems completed - in progress
**Muon Identification**: finds roads in identifier, matches well with tracker system, separates pions from muons

## Analysis and Performance Status--LANL Contributions

**Software:**
- LANL almost solely responsible for MuTr software development to this point; expect to need to continue to play large role in maintenance and development of data analysis algorithms (Melynda, Mike, Ming, Pat, ?)
- Columbia and UNM recently started effort to re-write software “framework”, but will keep the same analysis algorithms that are currently in use
- French contributing to replacement of one of the track-fitting methods as well as general infrastructure maintainence (tutorials, writing of data-summary-tape, writing of micro-DST, etc.)
- RIKEN, Columbia working on understanding alignment of tracker system
- ORNL and associated institutions responsible for Muon Identification software

## South Arm Performance Status--Noise and Calibration

- Station 2
- ~1.5 - 4.5

- Noise specs close to design, but not quite what is desired for long-term physics ()
- Calibration stability o.k.

## South Arm Performance Status--Chamber Resolution

- Chamber resolution not quite up-to-spec for real data--probably easily explained
- Resolution good enough for year-1 analysis and probably even year-2

## South Arm Performance Status--Other analysis software

- Alignment of tracker system still being worked on--required for track finding and reconstruction
- Monte Carlo studies indicate track finding and fitting working reasonably well though certainly some tuning is required
- Muon identifier suffered somewhat from higher occupancies than expected--partially corrected during run by shielding, will shield more next run.  Needs some more work reducing number of tracks found in MuID system
- / separation needs some more attention to reduce background rates

## South Arm: Analysis and Performance Status

- Plans for data reconstruction:
- First pass starting soon, to get data in time for Quark-Matter, July 2002
- Expect second-pass to fix alignment, etc.
- Physics Working Groups forming task forces now
- Software working groups separate from PWG: trying to resolve now
**Analysis of Year-1 data:**
- No students, but expressed interest to Heavy-Flavor group in j/psi and single-muon physics.  Potential analysis contributors:
- Melynda, Dave, Mike, Ming, Pat, Joel, new post-doc (April),
- In addition, interest expressed by:
- ORNL/UT - 2 students, 1-2 post-docs 2+ staff, long-standing role in muon identification (Au-Au physics primarily)
- RIKEN - 1 student (spin physics), several staff
- NMSU - 1 student, 1+ staff (j/psi polarization)
- Columbia - 1 student, 1 post-doc, 1+ staff (single muons from Au-Au, J/psi)
- French - focus on year-2 data but want to be involved with year-1 analysis

## Overall Schedule

- Analysis of Year-1 data
- Continued development of software and analysis tools for Year-2 data
- North arm assembly (pre-installation-chambers, electronics, etc.)
- Repair of South arm
- Installation of North arm chambers, electronics, plumbing, racks, alignment system, gas system, integration
**Shutdown begins now**
- _	__	_**Jan****	****Feb****	****Mar****	****Apr****	****May****	****Jun****	****Jul****	****staff**
**Year-1 analysis****	****	****	****	****	****	****	****	****?**
**North Chambers****	****	****	****	****	****	****	****	****6**
**N. FEE Assembly****	****	****	****	****	****	****	****2+**
**South Repairs****	****	****	****	****	****	****	****	****4-5**
**Chamber install,etc.****	****	****	****	****	****	****	****~6**
**FEE Install****	****	****	****	****	****	****	****	****~6**
**Next run:  October 2002 (or later)**