User name perdrisat
Log entry time 19:16:39 on November 5,2000
Entry number 51551
keyword=anomalies in the h.dp histo
Anomaly discovered earlier in the day was a sharp dip in the h.dp histo at about -0.04. This dip was seen in all runs with # larger or equal to 1064.
After looking at many histos, conclude that the dip exist only when all triggers are analyzed. When T5-events only are selected from the ntuple display, the acceptance in dp is strongly reduced, and the dip region contains nothing. So for the 3.5 GeV^2 data the dip is irrelevant. It may become more relevant in other kinematics, I will look into that.
When comparing h.dp with e.dp for T5 only, one see that one is mirror image of other , as should be. But then both show an extra bump superimposed on a trapezoidal shape. The origin of this bump is not understood; it survives when placing a trapezoidal cut on the elastic ridge in e.dp versus b.dp, so is not related to acceptance on continuum due to radiation.
To conclude: we have a problem of acceptance, in the form of a dip in h.dp in all runs starting at 1064; but it is outside of the dp region populated by elastic concidence events in the present kinematics.