attached are some results from my studies of muon pairs. I tried to find cuts which increase the contribtuions from muons from open charm production with respect to the other backgrounds. The largest background arises from Bethe Heitler Processes. These produce muon pairs which are correlated in their transverse components. You can see this in the plot in file "graphical_cut.ps" where I have plotted the x-component of the 2 muon momenta together with a 2d-cut (a graphical cut ) which I have applied later to the other events.
The naming convention of the attached files is as follows:
Therefore as an example the file : w_1.2_8.0_1.1.ps show invariant mass histograms for ptt2_min = 1.2 an e_max = 8.0 and w_min = 1.1 GeV
In addition files with gc have in addition the graphical cut applied mentioned above.
The different processes are labled as
In the future I will add the effects of the coherent spectrum. I think we could also use more events.
To summarize the largest effect on reducing the background comes from pt also in the muon pairs. With additional cute on w one can reduce the resonance contributions. I think we will have to study how to measure the muon total energy.
so thats all for now. I am off to JLAB where our D(ee'p) experiment just started to take data.
Werner U. Boeglin