1. MUC simulation and reconstruction
Zhengyun YOU
School of Physics , Peking University
Jan 10th, 2006

2. Outline μ/π Identification; Muon Chamber structure; Muc Simulation;
Muc Reconstruction;
μ/π Identification;
Summary;

3. Muon Chamber Structure
Barrel + EndCap;
RPC as μ detector;
Barrel : 9 layers
EndCap: 8 layers
One dimension read-out
strips;

4. Muc Simulation -- Geometry
All muc detector info stored in gdml file,
structure,
geometry,
materials…
Muc gdml file
GEANT4
Schema
Converted to Geant4 represented
geometry automatically by GDML
Geant4 Schema;
Detailed to each strip;

5. Muc Simulation -- Geometry
All muc detector info stored in gdml file,
structure,
geometry,
materials…
Converted to Geant4 represented
geometry automatically by GDML
Geant4 Schema;
Detailed to each strip;

6. Muc Simulation -- Digitization
RPC Gas Chamber as sensitive detector and strips as readout;
Project hits to nearby strips and set strips as fired;
No TDC and ADC info, only the strip fired or not;

7. Muc Reconstruction -- Geometry
GDML file
(same as Simu)
Muc geometry Initialization
MucGeoGeneral
MucGeoGap
MucGeoStrip
IMucGeomSvc
ROOT Geometry
Construct
GDML-ROOT Schema
MUC ROOT
Volume Ptr
Gap ROOT
Strip ROOT ::
Connect

8. Muc Reconstruction -- Algorithm
Use Ext Track from Mdc as seed;
Ext track
Fired strips
Window
Searching hits gap by gap;
Searching on Barrel first, then EndCap;
Also Searching on neighboring segments;
Line Fit with hits on track;
Compare with Mc truth;
Barrel
End Cap

9. Muc Reconstruction -- Efficiency
mu- cosθ(-0.9~0.9) 10,000 single mu- input event,
In comparison with MC truth, Reconstruction efficiency is
P (GeV/c)
0.5
0.75
1.0
Muc Reco Efficiency
> 93.33%
98.43%
98.93%
Num hits ~2 ~7 ~9

10. μ μ μ/π Identifcation π π 1.0GeV/c Input variables :
1. Depth of track in Iron ;
2. Max hits a layer contains;
Algorithm ：
Fisher (Linear); μ μ π π
1.0GeV/c

11. before entering Muc, limit
Simple μ/π Identification Efficiency
use Muc Info only %
91.2
90.3
μefficiency
87.6
18.9
12.6
15.0
π fake rate
6.24
Design Goal
9.0
12.0
6.0
9.0
5.5
GeV/c
Ratio of π decay to μ
before entering Muc, limit

12. Summary Muc simulation runs well in Boss5.0,
Next stage will focus on digitization;
Muc reconstruction also runs well, needs further study,
especially on low momentum and combination of barrel and end cap.
μ/π identification is just a simple model, much to do next.

13. Thank you!