Here I look at the systematic errors associated with the choice of cutoff parameters and number of bins used while doing the SVD unfolding ...

I look at two systematics related to the SVD unfolding scheme, a systematic associated with the choice of cutoff parameter and a systematic associated with the number of bins used in the unfolding.

The systematic associated with the choice of cutoff parameter is found by comparing the cross section calculated using the nominal cutoff value of six with the cross sections calculated using cutoff values of 5 and 7. In each bin, the largest variation between the nominal cross section and either the 5 or 7 cross section is the size of the systematic. That variation is added and subtracted from the nominal cross section to give the final symmetric systematic.

The other systematic associated with the SVD unfolding is the choice of number of bins used. I will show the cross section starting with the 19-23 GeV mass bin but I include a lower bin from 16-19 GeV while doing the unfolding. The bin choice systematic looks at the change in the cross section which arrises if I add another lower mass bin (13-16 GeV) while doing the unfolding. The systematic is calculated by finding the variation between the nominal cross section and the cross section computed with 12 bins. The size of the variation in each bin is the systematic for that bin and is added / subracted from the nominal cross section to give the final symmetric systematic.

The two systematics associated with the SVD unfolding are then added in quadrature. The cross section ratio with SVD systematic bands can be seen in figure 4.

Figure 1: This figure shows the (Data-Theory)/Theory curve for the data unfolded using SVD with a cutoff of 6 (Black), a cutoff of 5 (Red), and a cutoff of 7 (Blue). The 11 bin scheme was used and the theory used the CTEQ6M PDFs.

Figure 2: This figure shows the ratio of the cutoff systematic to the cross section.

Figure 3: This figure shows the ratio of the systematic associated with number of bins to the cross section. Note that the systematic in the first bin is undefined.

Figure 4: This figure shows the (Data-Theory)/Theory curve (Red) along with bands for the theory uncertainty (Blue) and the two SVD systematics added in quadrature (Black).