Track Correction Stuff ...

I presented my track correction scheme to the Jet Group on 10/25/11 and recieved many good comments. Based on the feedback, I have created several new plots which I present below.

One set of plots people were interested in seeing were the h+/h- ratios for tracks in the various sectors. A pdf containing the h+/h- ratios for the RFF and FF period can be found here.

There was also interest expressed in some details of the correlation plots I used to make my corrections. Specifically, people wanted to see how the distribution compared to what one would get if the correction was done without smearing.

Figure 1: This figure shows the modified RFF 1/pt vs unmodified RFF 1/pt. The RFF spectrum was modified using the gausian smearing described in previous posts. The smearing parameters are: Mean = 0.59, Sigma = 0.30 cm. The red triangles show the mean of the distribution along the X-axis for each bin in Y. The black squares show the relationship between the modified and unmodified RFF pts if we assume a constant sagitta shift of 0.59 with no smearing. The top plot shows positive tracks and the bottom plot shows negative tracks.

Based on the plots in figure 1, I have implamented two new back corrections schemes. To recap, in the scheme I have been using, I take the FF track pt and find the corresponding bin along the vertical axis in the plots from figure 1. I then find the mean (red triangle) and sigma of the X-distribution for that Y bin. I use those values to define a gausian from which I take a random value. That value is then my corrected pt.

The first new back correction scheme I have implamented in similar to the original scheme described above, for each FF pt I find the corresponding Y bin and then find the mean of the X distribution. In this scheme, I use the mean value as my corrected pt instead of constructing a gausian and finding a random value along the distribution.

In the second new back correction method, I just apply the sagitta correction directly assuming no smearing. So for each FF track pt, I find the sagitta and shift it by 0.59 cm in the appropriate direction and then use this modified sagitta to calculate my corrected pt.

Figure 2: This figure shows the results of the first new back correction scheme described above which uses the average values of the correlation distribution to do the correction. The black curve is the uncorrected FF spectrum, the blue curve is the RFF spectrum, and the red curve is the corrected FF spectrum. The top plot shows positive tracks and the bottom plot shows negative tracks.

Figure 3: This figure shows the results of the second new correction scheme described above which uses the constant sagitta shift. The black curve is the uncorrected FF spectrum, the blue curve is the RFF spectrum, and the red curve is the corrected FF spectrum. The top plot shows positive tracks and the bottom plot shows negative tracks.

Figure 4: For completness, I repost the results of my original back correction scheme. The colors are the same as above. As above, the top plot shows positive tracks and the bottom plot shows negative tracks. I have also added a set of plots which compare the positive and negative spectra in sector 20 before and after the correction.