Abstract: We investigate the systematic uncertainties associated with the conversion method.  Specifically, does the Monte Carlo indicate that the efficiency for passing the preshower-2 cut depends significantly on either pT or eta?

 

 

Method:

 

1. Generate 20k single gammas and pi0s with

    - flat eta distribution

    - exponential pT distribution consistent with the slope of the isolated event sample here

2. Create gamma trees.

3. Apply the cuts discussed in section 1 of the conversion method writeup.

4. Take the ratio of the number of particles passing the preshower-2 cut to the number of particles passing the isolation cut.

 

Figure 1 -- ε_gamma(pT) and ε_gamma(η).  MC is consistent with no significant pT or η  dependance.

 

 

Figure 1 -- ε_pi0(pT) and ε_pi0(η).  MC is consistent with no significant pT or η  dependance.

 

 

 

 

Conclusions:

 

1. Within the statistical precision of this event sample,  no significant variation with pT or eta is observed

2. We need more statistics, though... because a 5% deviation in the background efficiency corresponds to a large (~30%) deviation in the

3. We should also try to cross check any observed dependance with data, where feasible.