1. External Alignment Maya Shimomura (ISU)
Attempt to solve the problem of dφ alignment
12/02/23
VTX Meeting

2. The problem
Some parts of DCA distribution by standalone tracks are shifted.
Inner alignment shows the slope depending on φ.
 the ladder is tilted ?
 the radius is wrong ?
Check the external alignment (dφ) vs. φ distribution.
dφ vs. φ for B2 using pixel clusters
DCA West and East by SA tracks
Different color indicates different ladder in pixel dφ
Φ[rad]
Φ[rad]
12/02/23
VTX Meeting
Φ[rad]

3. Some ladders have slops
Not in CNT acceptance
Weak signal
Dead
slope
12/02/23
VTX Meeting

4. Attempt to solve 1 (did not work)
Make East coordinate shift with 190 microns along with x direction.
set_OffsetEastToWest(0.151,-0.010,0.)
set_OffsetEastToWest(0.113,-0.010,0.)
default : (unit is [cm]) set_OffsetEastToWest(0.132,-0.010,0.)
No hot dead map is applied.
12/02/23
VTX Meeting

5. dφ vs. vtx φ at B0 East (L5-9) Default Shift 1. Ladders have slopes.
12/02/23
VTX Meeting

6. dφ vs. vtx φ at B0 East (L5-9) Default Shift 2.
Attempt 2 looks better than 1.
Slopes are reduced.
12/02/23
VTX Meeting

7. dφ vs. vtx φ at B1 East (L10-19) Shift 2. Default
Slope became flatter than the default.
Phi center might be shifted.
12/02/23
VTX Meeting

8. dφ vs. vtx φ at B2 East (L8-15) Shift 2. Default
Small slope appeared ? ?
12/02/23
VTX Meeting

9. dφ vs. vtx φ at B3 East (L12-23) Shift 2. Default
No significant change is detected.
12/02/23
VTX Meeting

10. Peak position vs. ladder number (shift 2)
B0 West
B0 East
B1 West
B1 East
B2 West
B2 East
B3 West
B3 East
East has slope.
12/02/23
VTX Meeting

11. Attempt to solve 2
Since the whole shift for the east coordinate does not solve the problem, we decided to shift the ladder by ladder individually along each radius direction.
Calculate the amount of needed r-shift by fitting the profile slope of dϕ vs. ϕ distribution for each ladder.
Shift the r position for each ladder and create the new DST with this new geometry file. (waiting for finishing the jobs now.)
Will check if the DCA with standalone tracks are improved or not.
12/02/23
VTX Meeting

12. Fitting function Fitting function : y = [0]*tan(x-[1])
Parameter [0] is the necessary amount to shift.
Parameter [1] is the ϕ center position at each ladder where dϕ =0.
x is ϕ and y = dϕ here.
Track dϕ
ladder
In Software ϕ
Needed shift [0]
ladder
In Real
Fitting ϕ
profile
12/02/23
VTX Meeting

13. Condition and Selection
Run #349369
DST production is done in RCAS. (We have to use rcas instead of 1008 machines.)
Reconstruct from PRDF files ( under /phenix/zdata03/phnxreco/VTX/prdf/eventdata/)
Au+Au peripheral collision (10<BBC charge<200 )
-15<bbcz<15
Suppose the magnetic filed is uniform. (0.9 Tesla)
Coordinate systems are matched between VTX and CNT.
OffsetVtxToCnt :(-0.169,-0.122,0.)
X Y vertex
Xoffset = and Yoffset = for West
Hot dead map is applied.
Z vertex --- VTX vertex
VTX Meeting
12/02/23

14. DCA distribution before and after shift [0]
Before West
After West
Before East
After East
West around phi = 1 is slightly better than before ?
12/02/23
VTX Meeting

15. dϕ vs. vtx ϕ before and after shift
B0 West
After
B0-L0 and L4 became flatter than before.
12/02/23
VTX Meeting

16. dϕ vs. vtx ϕ before and after shift
B0 East
After
B0-East became steeper than before.
Looks like there are some phi shift occurred.
12/02/23
VTX Meeting

17. dϕ vs. vtx ϕ before and after shift
B1 West
After
B1-West became slightly flatter than before.
12/02/23
VTX Meeting

18. dϕ vs. vtx ϕ before and after shift
B1 East
After
B1-East became steeper than before.
Looks like there are some phi shift occurred.
12/02/23
VTX Meeting

19. dϕ vs. vtx ϕ before and after shift
B2 West
After
B2-West looks same before and after shift.
12/02/23
VTX Meeting

20. dϕ vs. vtx ϕ before and after shift
B2 East
After
B2-L8 became flatter and L12 became steeper than before.
Looks like there are some phi shift occurred.
12/02/23
VTX Meeting

21. dϕ vs. vtx ϕ before and after shift
B3 West
After
B2-L7 and L11 looks flatter than before.
12/02/23
VTX Meeting

22. dϕ vs. vtx ϕ before and after shift
B3 West
After
Looks like there are some phi shift occurred.
12/02/23
VTX Meeting

23. dϕ peak position vs. Ladder number
B0 West
B0 East
B1 West
B1 East
B2 West
B2 East
B3 West
B3 East
There are a lot of dϕ shift on East.
They have some structure as same as beam offset was shifted.
12/02/23
VTX Meeting

24. Shift [0] is better than –[0] at West?
DCA distribution before and after shift –[0] Just for the confirmation I tried opposite shift also.
Before West
After West
Before East
After East
Shift [0] is better than –[0] at West?
12/02/23
VTX Meeting

25. dϕ peak position vs. Ladder number with opposite sift (–[0])
B0 West
B0 East
B1 West
B1 East
B2 West
B2 East
B3 West
B3 East
There are a lot of dϕ shift on East.
They have some structure as same as beam offset was shifted.
12/02/23
VTX Meeting

26. Back Up
12/02/23
VTX Meeting

27. σ vs. ladder number (shift 2)
B1 West
B1 East
B0 West
B0 East
B2 West
B2 East
B3 West
B3 East
No strange behavior.
12/02/23
VTX Meeting

28. Possible reason In this case, we see the ϕ dependence. r ϕ DC track
Real hit
VTX layer Real position
VTX layer position in the software
Hit we see dϕ dϕ r ϕ
In this case, we see the ϕ dependence.
12/02/23
VTX Meeting

29. dφ vs. vtx z at B0 East (L5-9) West (L0-4)
Ladders at East have slopes.
12/02/23
VTX Meeting

30. dφ vs. vtx z at B1 East (L10-19) West (L0-9)
Some ladders at East have slopes.
12/02/23
VTX Meeting

31. dφ vs. vtx z at B2 East (L8-15) West (L0-7) East ladders have slopes.
12/02/23
VTX Meeting

32. dφ vs. vtx z at B3
West (L0-11)
East (L12-23)
12/02/23
VTX Meeting

33. Correlation cut is applied.
dφ correlation cut : dφ_{3} – dφ_{x} (x:0~2) < 2σ
 Background is reduced.
dϕ3 vs. dϕ1 (L5)
Red line y= ax +b
dϕ3 vs. dϕ1 (L5)
Red line y= ax +b
dϕ1 (B1L5)
dϕ1 (B1L5)
12/02/23
VTX Meeting

34. dφ vs. vtx φ before/after the correlation cut
The background is reduced.
However,,
the distribution is not significantly sharped as Yasuyuki expected.
The dead areas increase due to requiring the B3 correlation.
B1 West
Read: Average
(Profile)
12/02/23
VTX Meeting

35. Both run#349369 and run#349679 are in this period.
Zero field run
Zero field run ,
Zero field run ,
Zero field run , ,349007
Both run# and run# are in this period.
12/02/23
VTX Meeting

36. Calculation details on x-y plane
hit in VTX (xvtx,yvtx)
Distance(D) between the VTX hit and the straight line projection from (xoffset1,yoffset1) along the vector u can be calculated as the cross product (vector product) of vector x and vector u.
x = (xx,xy)=(xvtx-xoffset,yvtx-yoffset)
u = (ux,uy)=(cos(ϕ0),sin(ϕ0))
D = xx*uy - xy*ux
Track from (xoffset,yoffset)
Magnetic bending correction is approximated as
bend ~ 0.5*r2/R
r: length of vector x
Since p = 0.3*B*R
with B=0.9T
p ~ 0.27*R
1/R ~ 0.27/p
bend ~ *r2/p (r in cm)
u = (cos(ϕ0),sin(ϕ0))
initial direction of the CNT track used as the seed or guide
Beam center
(xoffset,yoffset)
12/02/23
VTX Meeting

37. Central Track Cut Track quality = 31 or 63 1.0<p[GeV/c]<4.0
|pc3dphi - emcdphi |<0.02
|pc3dz - emcdz + 0.2|<5.0
VTX Meeting
12/02/23

38. Mikhail’s slide
12/02/23
VTX Meeting