Slide 1:

1. The initial Z-vertex Distribution:

The z-vertex is distributed almost flat between -32 and +32. The following plot shows the distribution before (black) and after(red) the z-cut.

The entries before zcut = 380000

The entries after zcut = 259111

Eff = 0.6819, so we lose about 31.8% of D0s here by this cut.

Slide4 (Pt:mass Plot)

1. Efficiency after applying cuts on Si hits and Tpc hits

Cuts	No. of Entries	Efficiency
No Cuts	51801	-
TpcHits>20(pos&Neg)	50511	97.5%
SiHits>2(pos&Neg)	9818	18.95%
SiHits>2&&TpcHit>20(pos&Neg)	9651	18.63%

Slide5(mass plot):

2. mass plot with cuts on the number of Hits in Si and Tpc:

We get a sigma of 10. 9(no cuts) to 10.66MeV(SiHits), which is consistent with what Stephen got.

Plot logY in these histos and do a fit without the background due to wrong associations.

Cuts	Chi^2/ndf	Entries	Efficiency
No Cuts	907/20	51801	-
TpcHits>20(pos&Neg)	847.6/20	50511	97.5%
SiHits>2(pos&Neg)	60.46/13	9818	18.95%

By eliminating the background the Chi^2 reduces from 1260/85(too high) to 907/20 in the no cut case.

Slide 6(mass plot with eta cut):

3. Efficiency after cutting on the eta of daughters.

Cuts	Entries	Efficiency
No Cuts	51801	-
|EtaPos| < 0.6	31045	59.93
|EtaNeg| < 0.6	30461	58.80
|EtaPos|<0.6&|EtaNeg|<0.6	18647	36%

Slide 7(pT Resolution):

4. A slope of 3MeV is expected for the mean (pT_RECO – pT_GEANT).

5. Do we apply any correction to the dEdX of K and pi? – Not yet.

mean(pT_RECO – pT_GEANT)

A slope of 3MeV is expected due to the decreasing D0 mass with pT increase. Here the slope is 2.17+-0.1MeV, which is in agreement with the above.

Plot the mean pT of the daughters:

Mean pT of daughters:

Slide 8(sigma = σ_{(pTRECO – pTGEANT/pTGEANT)} )

6. Plot the sigma , σ_{(pTRECO – pTGEANT/pTGEANT)}

For sigma single track resolution is not expected.

Slide10:

7. Lots of decay lengths with negative values for the RECO( probably due to resolution of the Si detectors )

Later works on decay Length Resolution can be found on this page