A preliminary Muon Identification result

1. A preliminary Muon Identificationresult You Zhengyun School of Physics , PKU 2005.11.23

2. Outline Muon ID variables; Muon ID algorithm; Muon ID result; Next work;

3. 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 ) ,

4. MuonID Variables Input variables : 1. Depth of track in Iron ; 2. Max hits a layer contains; 1.0GeV/c

5. MuonID Variables Input variables : 1. Depth of track in Iron; 2. Max hits a layer contains; 0.75GeV/c

6. MuonID Variables Input variables : 1. Depth of track in Iron; 2. Max hits a layer contains; 0.5GeV/c

7. 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;

8. YCut =3.2 MuonID @ 1.0GeV/c

9. MuonID @ 1.0GeV/c Log YCut =3.2

10. MuonID @ 0.75GeV/c YCut =2.0

11. MuonID @ 0.75GeV/c Log YCut =2.0

12. MuonID @ 0.5GeV/c YCut =0.5

13. MuonID Efficiency 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;

14. YCut could be adjusted Global : MucRec + MuID For all tracks with |Cos θ| < 0.9 % YCut =2.0 YCut e.x @ 0.75GeV/c, YCut = 2.0 is the best when mu:pi = 1:1

15. Next Work More detailed MC samples to get a set of parameters and ycut; Consider more variables; Other identification algorithm;

16. Thank you !

18. 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

19. Efficiency 1.0 GeV cosθ(-0.9~0.9) mu 10,000 single track 0 hits : 236 Perfect Reco Tracks (Lost 0) : 9609  5000 as mu: 5000-441=91.18%, no hits 109 Other Tracks (Lost >0) :155 pi 30,000 single track 0 hits : 16974 Perfect Reco Tracks (Lost 0) : 28382  5000 as mu: 346 = 6.92%, no hits 2827 Other Tracks (Lost >0) : 1618 yCut = 3.2; Global Test mu 5000 : 4471 = 89.42% Test pi 5000: 312 = 6.24%

20. Efficiency 0.75 GeV cosθ(-0.9~0.9) mu 10,000 single track 0 hits : 220 Perfect Reco Tracks (Lost 0) : 9443  5000 as mu: 5000-329=93.42%, no hits 100 Other Tracks (Lost >0) :557 pi 48,000 single track 0 hits : 31645 Perfect Reco Tracks (Lost 0) : 47409  5000 as mu: 652 = 13.04%, no hits 3193 Other Tracks (Lost >0) : 591 yCut = 2.0; Global Test mu 5000 : 4561 = 91.22% Test pi 5000: 639 = 12.78%

21. Efficiency 0.5 GeV cosθ(-0.9~0.9) mu 10,000 single track 0 hits : 1218 Perfect Reco Tracks (Lost 0) : 9468  5000 as mu: 5000-618=87.64%, no hits 618 Other Tracks (Lost >0) :155 pi 90,000 single track 0 hits : 79393 Perfect Reco Tracks (Lost 0) : 95835 5000 as mu: 948 = 18.96%, no hits 4052 Other Tracks (Lost >0) : 1618 yCut = 0.5; Global Test mu 5000 : 4250 = 85% Test pi 5000: 946 =18.92 %