Possible Issues at Eta=4.0 and Cos(phi)=-1

There has been a question of whether the large AN at small pt for Energy ~ 50 GeV could be related to a possible problem in the detector near eta=4.0

and cos(phi)=-1.


This is the 1 parameter fit for that region 4.1>Eta>3.9 and 40<Energy<60, .04<Mass<.3

I do not see evidence of one region that is making this slope large. Note: the chi2 is 4.5 for 9 DOF.