1. Physics with the HFT prototype?
Motivation
Results of simulation :
Acceptance optimization studies
Tracking efficiency studies with TPC+PXL
Next steps
J. Bouchet for the HFT-soft group
8/2/2018
Star Coll. Meeting, LBNL, Nov. 2011

2. Star Coll. Meeting, LBNL, Nov. 2011
Motivation
PIXEL detector is the inner sub-system of the HFT tracker in STAR
3 (or 2 or 4) PXL sectors (out of 10) will be installed in STAR next year for Run-13 as an engineering run
Question : Which geometry is the most efficient for track pointing and physics measurement ?
for low Pt D0, opening angle between daughters is large.
For higher Pt D0, the opening
angle decreases.
Different Pt D0 regimes lead to
different configurations of the sectors.
cosine(φpion-φkaon) vs. PtD0
8/2/2018
Star Coll. Meeting, LBNL, Nov. 2011

3. 2 configurations studied
=108
=72
=144
=36
=180
=0
=216
=324
=252
=288
Triangle-shape
Joined-shape
1 sector covers 36
8/2/2018
Star Coll. Meeting, LBNL, Nov. 2011

4. Star Coll. Meeting, LBNL, Nov. 2011
Simulation Setup
Input:
Generate 100k D0 with flat Pt in [0,5], ||<3,|Vz|<10 cm
Count :
NN : # of D0 input
N0 : # of D0 after Pt cut for both daughters and|| <1
N1 : # of D0 with above cuts + TPC>10,PXL=2
N2 : # of D0 in triangle configuration
N3 : # of D0 in joined configuration
Single track efficiency/ghosting
Modify the existing geometry file with
Removal of SSD and IST
Localization of 3 pxl sectors according the patches configuration
~500 central AuAu Hijing events but NO PILEUP
Plus minbias AuAu hijing events for creating pile-up
8/2/2018
Star Coll. Meeting, LBNL, Nov. 2011

5. Cuts on Daughters: ||<1, TPC>10,PIXL=2, triangle(N2)
8/2/2018
Star Coll. Meeting, LBNL, Nov. 2011

6. Cuts on Daughters: ||<1, TPC>10,PIXL=2, triangle(N3)
8/2/2018
Star Coll. Meeting, LBNL, Nov. 2011

7. What physics can be achieved ?
Can we do anything substantial here ?
Any physics with the prototype?
Charm cross-section
Charm Rcp
8/2/2018
Star Coll. Meeting, LBNL, Nov. 2011

8. TPC+PXL Efficiency/ghosting studies
BFC chain reconstruction and tracking (Sti) with only pixel prototypes geometry = no material form SSD nor IST.
350 hijing events, no pile up.
Vertex cuts :
|Vreco -VMC| < 0.01 cm : good reconstruction vertex
|Vreco | < 10 cm
Tracks cuts :
Reco TPC hits >15
|η|<1
The definition is :
effSiGoodRc = # of tracks with 2 good pixels hit / # of tracks with 2 MC pixel hits
Ghosting = # of tracks with 2 good pixels hits / # of tracks with 2 pixel hits
8/2/2018
Star Coll. Meeting, LBNL, Nov. 2011

9. Star Coll. Meeting, LBNL, Nov. 2011
Efficiency with TPC+PXL prototype
Good tracking efficiency (but no pile-up yet)
Hijing – NO Pile-up
TPC+PXL
TPC+SSD+IST+PXL
8/2/2018
Star Coll. Meeting, LBNL, Nov. 2011

10. Star Coll. Meeting, LBNL, Nov. 2011
Ghosting with TPC+PXL prototype
Low Ghosting
Hijing – NO Pile-up
TPC+PXL
TPC+SSD+IST+PXL
8/2/2018
Star Coll. Meeting, LBNL, Nov. 2011

11. Star Coll. Meeting, LBNL, Nov. 2011
Next steps
Include pile-up events :
Will increase single track ghosting
Study reconstruction of D0 in this environment
So far it looks encouraging
We have two configurations for x-section and Rcp measurements (if everything else goes well)
Please think of what physics YOU would like to do. We will help you run the simulation.
8/2/2018
Star Coll. Meeting, LBNL, Nov. 2011

12. Star Coll. Meeting, LBNL, Nov. 2011
Back-up
8/2/2018
Star Coll. Meeting, LBNL, Nov. 2011

13. Star Coll. Meeting, LBNL, Nov. 2011
SSD+PXL
SSD layer
Pixel outer layer
Pixel inner layer
Note : the x-axis scale changes with the layer
8/2/2018
Star Coll. Meeting, LBNL, Nov. 2011

14. Star Coll. Meeting, LBNL, Nov. 2011
PXL only
SSD layer
Pixel outer layer
Pixel inner layer
Note : the x-axis scale changes with the layer
8/2/2018
Star Coll. Meeting, LBNL, Nov. 2011

15. Star Coll. Meeting, LBNL, Nov. 2011
comments
With SSD :
Residuals in r/phi for the outer pixel layer is better than w/o SSD
Residuals in r/phi for the inner pixel are slightly better than w/o SSD
Residuals in r/phi and Z are asymetric (due to the asymetric resolution of SSD) for both outer and inner layer
w/o SSD:
Residuals in r/phi and Z are symmetric (due to the same resolution of the pixel)
8/2/2018
Star Coll. Meeting, LBNL, Nov. 2011

16. Some precautions to make
Optimization wrt TPC sectors :
TPC has 12 sectors
PIXEL has 10 sectors
2. TPC sectors health during a physics run : we want to avoid to place a PXL sector matching a unhealthy TPC sector
8/2/2018
Star Coll. Meeting, LBNL, Nov. 2011

17. Star Coll. Meeting, LBNL, Nov. 2011
8/2/2018
Star Coll. Meeting, LBNL, Nov. 2011

18. Star Coll. Meeting, LBNL, Nov. 2011
MRPC ToF barrel
100% ready for run 10 (now!)
BBC
PMD
FPD
FMS
EMC barrel
EMC End Cap
DAQ1000
FGT
Completed
Ongoing
MTD
R&D
HFT
TPC
FHC
HLT
8/2/2018
Star Coll. Meeting, LBNL, Nov. 2011