1. 1 Simulation, Formatter & Analysis Kyo Tsukada Tohoku Univ.

2. 2 Geant4 simulation /home/cvs/NKS2/dev/simulation/ Geometries of OH and EV are read from hodogeo.param. Geometries of IH and DC are directly written in “NksDetectorConstruction.cc”. Target Position is read from target.param. Now, Polarity of the magnetic field is Opposite. Generated particles, Momentum, Angle and position are read from beam/xxx.param. How to run…  (1)./bin/nks2 xxx.conf  (2)./bin/nks2 xxx.conf xxx.mac (xxx.root xxx.dat)

3. 3 Simulation -- output We can see the geometries by OpenGL. “NksAnalysis.cc” generates a root file & a text file. Format of the text file is ↓, OH EV Coil Vacuum Chamber Target & IH In this picture, Chambers and Magnet Yoke are invisible.

4. 4 Formatter /home/cvs/NKS2/dev/formater Formater create the raw data using the text output of Geant4 simulation. Input & output files are assigned in conf file. Various resolutions & efficiencies are also defined in conf file. Drift times of chamber are calculated by a assumption. How to run… -->./bin/formater xxx.conf (xxx.hbook)

5. 5 Drift length of chamber For each hit, the positions and directions of two points are saved. From (x1,y1,z1), (x2,y2,z2), (dx1,dy1,dz1) and (dx2,dy2,dz2), a radius and center position of a circle (screw) can be estimated. Then, the distance between the screw and neighbor wires are calculated. position direction position direction (previous)

6. 6 Analyzer Both data of chamber and hodoscope are included in one raw data file. How to analyze.. ./bin/analysDSPiPlusPiMinus3D xxx.con xxx.root xxx.dat xxx.dat The momenta, generation points, vertex points and momenta of decayed particles of K 0 and  are also saved in the raw data. –CID : 5 (Misc) –Slot : CAMAC 22 - By “SimAnalysis.h, cpp”, these information can be used. Same!!

7. 7 Missing wires in forward region Layer#Wire# 118, 30, 33 2 3 434 534, 35 644, 45, 46 745, 46 860, 61 9 1072 1172, 73 1288 1388, 89 The influence of the missing wires are large? Or small?.

8. 8 Acceptance for K 0 The acceptances are estimated for both cases, that is, the missing wires exit or not. The number of events used is only 500000 events. The cut conditions are “Decay Volume Cut” and “Opening Angle Cut -0.9<cosOA<0.8”. The acceptances are not so different. The “missing wires” don’t exist.The “missing wires” exist. GeneType : K0, uniform P [GeV/c] cos 

9. 9 Acceptance for  The conditions are almost same with that of K 0 (previous page). #Event = 500000 Only “Decay Volume Cut” The influence of “Missing wires” is larger than that of K 0. GeneType : Lambda, uniform The “missing wires” don’t exist.The “missing wires” exist. P [GeV/c] cos 

10. 10 Chamber resolutions We estimate the chamber resolutions by “UserDCEfficiency.cpp”. But, the resolutions include the resolution of the trajectory. Simulation data : arbitrary resolutions can be assumed. GeneType : K0, uniform 150mm for SDC and 200mm for CDC are reasonable. (?) The resolution of trajectory is large….

11. 11 momentum – beta correlation Gene Type: K0Lambda As per usual…

12. 12 Momentum resolutions -- calculation by MThesis of K. Futatsukawa By using typical values, the momentum resolution is about 1-2 %.  x =200-500  m, n=4-9, l=80cm, B=0.42T, X 0 =34100cm, X=l PXY=0.3-0.5GeV/c

13. 13 aside By using following value, –  x =300mm –n=6 –l=13cm –B=0.42T –X 0 =34100cm –X=l –PXY=0.1GeV/c dp/p = 12%

14. 14 Momentum resolutions -- simulation (K 0 ) The momentum resolution of  form K 0. The definition : dp = p(sim) – p(ana). The momentum resolution is about 2  4 % ( 9% for vertical track ). I cannot understand why the resolution of  is better than that of    GeneType : K0, uniform

15. 15 Momentum resolutions -- simulation (  ) The momentum resolution of p  form . The momentum resolution is about 4-6 % ( 10-25% for vertical ). For proton, absolute value is estimated to be large.  proton GeneType : , uniform

16. 16 Opening Angle for K 0 The opening angle of  form K 0. Two curves are shown in the correlation of the opening angles (Left Figure). The derivation of vertex point should be improved? GeneType : K0, uniform

17. 17 Opening Angle for  The opening angle of p  form . The same problem exist. GeneType : , uniform

18. 18 Opening angle resolution ? Now, we cannot correct the emission angle dependence of the opening angle. p 

19. 19 Vertex resolutions The vertex resolution for  and p . Condition : Opening Angle Cut for K 0 The resolutions are not so good…. p 

20. 20 Mass resolutions The invariant mass spectra of  p . Conditions : –Decay Volume Cut & Opening Angle Cut for K 0 –Decay Volume Cut for  p 

21. 21 K 0  measurement 4-tracks analysis Almost no cut Lambda is clearly seen. K0 is … ? By the simulation, we can estimate the number of K 0. Reasonable? GeneType : K 0  KMaid

22. 22 K +  measurement 2-Track analysis. Although we may detect K +, the K + is, now, measured as a missing particle. The gamma energies are discrete by 6 MeV. GeneType : K +  KMaid Target : proton at rest