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Motivation Results of simulation : Acceptance optimization studies Tracking efficiency studies with TPC+PXL Next steps. Physics with the HFT prototype?. J. Bouchet for the HFT-soft group. Motivation. PIXEL detector is the inner sub-system of the HFT tracker in STAR
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Motivation • Results of simulation : • Acceptance optimization studies • Tracking efficiency studies with TPC+PXL • Next steps Physics with the HFT prototype? J. Bouchet for the HFT-soft group 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 Star Coll. Meeting, LBNL, Nov. 2011
2 configurations studied =108 =72 =144 =36 =180 =0 =216 =324 =252 =288 Triangle-shape Joined-shape 1 sector covers 36 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 Star Coll. Meeting, LBNL, Nov. 2011
Cuts on Daughters:||<1, TPC>10,PIXL=2,triangle(N2) Star Coll. Meeting, LBNL, Nov. 2011
Cuts on Daughters:||<1, TPC>10,PIXL=2,triangle(N3) Star Coll. Meeting, LBNL, Nov. 2011
What physics can be achieved ? • Can we do anything substantial here ? • Any physics with the prototype? Charm cross-section Charm Rcp Star Coll. Meeting, LBNL, Nov. 2011
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 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 Star Coll. Meeting, LBNL, Nov. 2011
http://www.star.bnl.gov/protected/jetcorr/kapitan/HFT/upgr15_2010/productionQA/thin/CD1/single/http://www.star.bnl.gov/protected/jetcorr/kapitan/HFT/upgr15_2010/productionQA/thin/CD1/single/ Ghosting with TPC+PXL prototype • Low Ghosting Hijing – NO Pile-up TPC+PXL TPC+SSD+IST+PXL 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. Star Coll. Meeting, LBNL, Nov. 2011
Back-up Star Coll. Meeting, LBNL, Nov. 2011
SSD+PXL SSD layer Pixel inner layer Pixel outer layer Note : the x-axis scale changes with the layer Star Coll. Meeting, LBNL, Nov. 2011
PXL only SSD layer Pixel inner layer Pixel outer layer Note : the x-axis scale changes with the layer 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) Star Coll. Meeting, LBNL, Nov. 2011
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 Star Coll. Meeting, LBNL, Nov. 2011
MTD EMC barrel MRPC ToF barrel 100% ready for run 10 (now!) EMC End Cap FMS BBC FPD TPC FHC PMD DAQ1000 Completed HLT Ongoing R&D HFT FGT Star Coll. Meeting, LBNL, Nov. 2011