1. VTX tracking issues
Y. Akiba

2. Working directories Data (copied by Hachiya-san)
/common/s10/phnxreco/prdf
127 file segments from RUN349679
Reconstruction (set up by Hachiya-san)
/home/phnxreco/run11/testmacros/svxtest
run.csh run reconstruction code
Fun4All.C actual reco macro
Analysis code
/common/s7/vtx/akiba/svxana
svxana.cc analysis code
/common/s7/vtx/akiba/svxana/wrk
run_svxana2.C run analysis code.

3. Update on SvxStandAloneReco
As it is shown in the software meeting on Monday, the beam spot size is shifted by ~2 mm. This needs to be corrected.
Beam position in West VTX (x>0) and East VTX (x<0) is also different by ~1mm.
Implement “beam center” and “East offset”
Usage: (in Fun4All.C)
Here beam center is set to (0.23,0.045)
East offset is set to (-0.14,-0.01)
New members

4. Calculate (approx) 2D DCA
Magnetic field ~ 0.9T
L0 at 2.5cm = 0.025m
L1 at 5cm
L=0.025m 2d d 3d
Straight line projection from L0 and L1 hit can be corrected by 0.017cm/p (p in GeV/c)
Here p is pT measured by StandAloneReco

5. Bend corrected DCA vs phi0
East VTX
West VTX
East VTX
DCA (cm)

6. DCA (part of the detector)
P>1 GeV
s = 139 um
P>1 GeV
s = 126 um
2d DCA resolution relative to beam center is
139 um for p>1 GeV/c and 126 um for p>2 GeV/c
This is actually the beam spot size.
The beam spot size I calculated from the RHIC parameters is about 130 um for Au+Au at 200 GeV.
Is it too good?

7. Structure in DCA New geom is better at West VTX, but worse in East
Using the most-recent SvxPISA.par
(prepared by Asano-san and in CVS)
Using the “original” SvxPISA.par
(when Hachiya-san set up svxtest dir)
New geom is better at West VTX, but worse in East
Is the correction applied in the wrong direction in the East?

8. Comparison of West
New SvxPISA.par
For the West, zig-zag structure seems to be reduced.

9. Structure is related to ladder
Color by L0 ladder ID
Color by L1 ladder ID
Different color corresponds to different ladder (L0 and L1)
The structure corresponds to ladder division
It should be possible to adjust ladder position/orientation to eliminate the structure
 Asano-san volunteered to do this.

10. Association to Central Track
Difference of theta angle of VTX track and
CNT track. (|dphi|<0.3, p>0.5 GeV/c)
Difference of phi angle of VTX track and
CNT track. (|Dtheta|<0.2, p>0.5 GeV/c)
For all VTX tracks with p>0.5 GeV/c, calculate difference in phi and theta with all CNT tracks
For CNT tracks, (the0, phi0) (emission angle at R=0) is used
Good news: Clear peaks are seen.
Bad news: the phi angle has two peaks! (problem. Should be one.)

11. Two peaks…charge dependent
Two peaks corresponds to charge of the CNT track.
The peak position should be the same. This is a problem in CNT track model.
Part of the problem can be due to the shift of the beam center. To be investigated.