Anomalous behavior of the ratio of counts of high pT particles as a function of charge sign have been seen in the initial attempt to produce Run 17 st_W stream data for the W analysis (P17ig). This was shown in slide 4 of You do not have access to view this node. I have included the relevant pT distributions of high pT primary tracks in the left plots below. In the upper right, I have tried to make a simple representation of the primary track pT distribution as A*p_T^B, with A=2e7, B=-2.83. In the lower right, I have used the interpreted impact of GridLeak models on primary tracks of δ(p_T) = 0.005*p_T² to demonstrate the impact on h^-/(h^- + h⁺).

A few comments:

1. The real data is clearly not a perfect power law (particularly at low p_T), so my simple model is not a very accurate replication, but is at least loosely illustrative.
2. I am uncertain I have the sign of the impact correct for whether h^-/(h^- + h⁺) increases or decreases when switching models - I have simply chosen a sign to match that of the observation in real data.
3. There should be an even larger impact on global tracks, but the real data did not show much of an issue for global tracks.

Here is another version of the lower right plot from above, but with minima and maxima expanded to [0,1]:


-Gene