Uncertainty Study

Uncertainty
Source of Error Estimated Value
Forward/Back Comparison
Cosmics0%
Ratio Fits
Slope Fits1%
Theory

Backgrounds

We rerun the analysis with the requirement that pairs be unlike-sign removed and note how much doubling the background affects the results.
Five Parameter fit. Fitting scheme for the minbias set, 0.0 < y < 0.5. Plot with statistics here. (left panel)

Five Parameter fit. Fitting scheme for the minbias set, 0.5 < y < 1.0. Plot with statistics here. (right panel)


Five Parameter fit. Fitting scheme for the topology set, 0.05 < y < 0.5. Plot with statistics here. (left panel)

Five Parameter fit. Fitting scheme for the topology set, 0.5 < y < 1.0. Plot with statistics here. (right panel)


Detector Modelling

Fitting scheme for minbias set, 0.0 < y < 0.5, using R(t) from uncorrected MC t distributions.


Fitting scheme for minbias set, 0.5 < y < 1.0, using R(t) from uncorrected MC t distributions.


Fitting scheme for topology set, 0.05 < y < 0.5, using R(t) from uncorrected MC t distributions.


Fitting scheme for topology set, 0.5 < y < 1.0, using R(t) from uncorrected MC t distributions.


Fitting Uncertainty

Ratio Fitting


A summary of the error derived by varying the ratio fits. The standard deviation of the statistical errors on the c parameter are calculated. The fits can be found here.
Fit Error
minbias
0 < y < 0.5
0.00271
minbias
0.5 < y < 1.0
0.00327
topology
0.1 < y < 0.5
0.00917
topology
0.5 < y < 1.0
0.0523

Slope Fits


A summary of the c parameters obtained by fixing the exponential slope parameter (k) in the overall fit to 100%, 90%, and 80% of its correct value. The fits can be found here.
Dataset 100% 90% 80%
minbias
0 < y < 0.5
1.01 1.00 0.99
minbias
0.5 < y < 1.0
0.92 0.91 0.91
topology
0.1 < y < 0.5
0.83 0.83 0.87
topology
0.5 < y < 1.0
1.04 1.04 1.10

Theory Uncertainty

Two main models predict and describe the interference effect we see in the data. STARlight is the Monte Carlo event generator algorithm which is used in this analysis. It is based on theory and calculations by Klein and Nystrand. The other model is by Hencken, Baur, and Trautmann (HBT) .

KNLite Comparisons

Extensive predictions and comparisons have been made with the KNLite model by Jim Draper.

STARlight Comparisons


Figure 1 & 2:

Comparisons between STARlight and the Hencken, Baur, Trautmann (HBT) model. On the left are curves representing predictions for events without nuclear excitation. On the right are curves representing events with multiple neutron excitation. The curves have been normalized so that the area under the curves is equal to 1. The nuclear radius in STARlight has been adjusted to match the data as described here.

Figure 3 & 4:

Comparisons between STARlight and the Hencken, Baur, Trautmann (HBT) model. The curves in each of the plots represent predictions for events without nuclear excitation. On the left the STARlight curve includes a hard sphere approximation. On the right, the STARight curve is without the approximation. The curves have been normalized so that the area under the curves is equal to 1. The nuclear radius has not been adjusted to match the data as in figures 1 & 2.