Download - A preliminary Muon Identification result
A preliminary Muon Identification
result
You ZhengyunSchool of Physics , PKU
2005.11.23
Outline
Muon ID algorithm;
Muon ID result;
Muon ID variables;
Next work;
MuonID Samples
Train Samples :
Mu (True) & Pi (False) Reco. Tracks.Use Perfect Reco tracks only (all associated mc hits found)
5000 tracks at each Discrete Momentum ( @ 0.5, 0.75 and 1.0 GeV/c ) ,
MuonID Variables
Input variables : 1. Depth of track in Iron ; 2. Max hits a layer contains;
1.0GeV/c
MuonID Variables
Input variables : 1. Depth of track in Iron; 2. Max hits a layer contains;
0.75GeV/c
MuonID Variables
Input variables : 1. Depth of track in Iron; 2. Max hits a layer contains;
0.5GeV/c
MuID Alogrithm
Project n-dim variables space to 1-dim line. g : average of input variable vector;S : covariance of input variables;
T=S1+S2 ω=T-1(g1-g2) Y = ωt * x;
Use two samples mu and pi to get a Transform Vector ω, Which could separate two samples best, and determine a YCut;
Test :For an unknown sample to be tested, Use input variable x to get a y, compare it with YCut to determine whether it belongs to mu or pi;
MuonID @ 1.0GeV/c
YCut = 3.2
MuonID @ 1.0GeV/c Log
YCut = 3.2
MuonID @ 0.75GeV/c
YCut = 2.0
MuonID @ 0.75GeV/c Log
YCut = 2.0
MuonID @ 0.5GeV/c
YCut = 0.5
MuonID Efficiency
GeV/c
%
0.5 0.75 1.0
Mu Efficiency
87.64 93.42 91.18
Pi
Fake rate18.96 13.04 6.92
Mu Efficiency
85.00 91.22 89.42
Pi
Fake rate18.92 12.78 6.24
MuID Alg
Global :MucRec + MuID
For all tracks with|Cos θ| < 0.9
Mis-identified muon includes : 1. Lost hits by Acceptance; 2. Lost hits by muc reconstruction;3. All hits found, but mis-identified as pion by MuonID Algorithm;
YCut could be adjusted
Global :MucRec + MuID
For all tracks with|Cos θ| < 0.9
0
10
20
30
40
50
60
70
80
90
100
1 1. 2 1. 4 1. 6 1. 8 2 2. 2 2. 4 2. 6 2. 8 3
mupi
YCut
e.x @ 0.75GeV/c, YCut = 2.0 is the best when mu:pi = 1:1
YCut = 2.0
%
Next Work
Consider more variables;
More detailed MC samples to get a set of parameters and ycut;
Other identification algorithm;
Thank you !
图 6 进入 μ子鉴别器之前 , π介子衰变成μ子的比率随动量的分布
Efficiency
1.0 GeV cosθ(-0.9~0.9)
mu 10,000 single track0 hits : 236Perfect Reco Tracks (Lost 0) : 9609 5000
as mu: 5000-441=91.18%, no hits 109Other Tracks (Lost >0) :155
pi 30,000 single track0 hits : 16974Perfect Reco Tracks (Lost 0) : 28382 5000
as mu: 346 = 6.92%, no hits 2827Other Tracks (Lost >0) : 1618
yCut = 3.2; GlobalTest mu 5000 : 4471 = 89.42%Test pi 5000: 312 = 6.24%
Efficiency
0.75 GeV cosθ(-0.9~0.9)
mu 10,000 single track0 hits : 220Perfect Reco Tracks (Lost 0) : 9443 5000
as mu: 5000-329=93.42%, no hits 100Other Tracks (Lost >0) :557
pi 48,000 single track0 hits : 31645Perfect Reco Tracks (Lost 0) : 47409 5000
as mu: 652 = 13.04%, no hits 3193Other Tracks (Lost >0) : 591
yCut = 2.0; GlobalTest mu 5000 : 4561 = 91.22%Test pi 5000: 639 = 12.78%
Efficiency
0.5 GeV cosθ(-0.9~0.9)
mu 10,000 single track0 hits : 1218Perfect Reco Tracks (Lost 0) : 9468 5000
as mu: 5000-618=87.64%, no hits 618Other Tracks (Lost >0) :155
pi 90,000 single track0 hits : 79393Perfect Reco Tracks (Lost 0) : 95835 5000
as mu: 948 = 18.96%, no hits 4052 Other Tracks (Lost >0) : 1618
yCut = 0.5; GlobalTest mu 5000 : 4250 = 85%Test pi 5000: 946 =18.92 %