Study of importance of Esmd hit resolution
Updated: Wed Jan 10 15:58:01 EST 2007

Question: How much charge & pT reconstruction depends on accuracy of E-SMD hit.

  1. General method: as desribed here, geometry UPGR12,

  2. electrons w/ pt=30 GeV/c.

  3. Tracking uses: vertex+FST+FGT+TPC+ESMD.

  4. Used detector configurations:
    * config=D : FST=1+4, FGT=1+3, ESMD=yes, varied sigma Esmd=0.5,1,2,3 mm
    * config=G : FST=1+4, FGT=1+3, ESMD=no

  5. Resulting charge reco efficiency & pT resolution for electrons w/ pt=30 GeV/c.
    Primary vertex & TPC are used in all configurations. Statistical error of efficiecny is of 0.01 to 0.02.
    Config D05: ESMD=yes sigEsmd=0.5mm
    Pt resolution=(1/Rrec-1/Rgen) / 1/Rgen vs. eta for 3 zVertex positions
    Config D1: ESMD=yes sigEsmd=1.0mm
    Pt resolution=(1/Rrec-1/Rgen) / 1/Rgen vs. eta for 3 zVertex positions
    Config D2: ESMD=yes sigEsmd=2.0mm
    Pt resolution=(1/Rrec-1/Rgen) / 1/Rgen vs. eta for 3 zVertex positions
    Config D3: ESMD=yes sigEsmd=3.0mm
    Pt resolution=(1/Rrec-1/Rgen) / 1/Rgen vs. eta for 3 zVertex positions
    Config G: ESMD=no
    Pt resolution=(1/Rrec-1/Rgen) / 1/Rgen vs. eta for 3 zVertex positions

  6. Conclusions
    1. For zVertex [-30,0] cm and track eta<1.8 one expects small increase (below 10%) in the charge & pt reco accuracy - the more precise the Smd hit is the better.
    2. For zVertex=+30 cm, adding Smd hit recovers eta range [1.2, 1.6], but ... in UPGR12 geometry such tracks miss completely FST & FGT. With optimized location of new detectors the Smd hit will be less important.
    3. Smd hit improves accuracy of pT reco, which however will be measured in EEMC towers anyhow. Especialy if sigma of the SMD point is about the sigma of TPC hits assumed to be 1mm.