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Greetings,<br>
<br>
I looked into the workings of vert2. The method of obtaining the
vertex for 2 tracks in this method is no different than the method I
have been using for years. The problem with this method is that it
will fail if the tracks are parallel, which is usually the case for
conversions and low mass e+e- events (the problem are in which we
are investigating).<br>
<br>
Below is a the snipet of the code to prove it<br>
<br>
<font color="#3366ff"> /*calculate dot product of direction unit
vectors*/<br>
R = v3dot(line1.dir,line2.dir);<br>
<br>
if(R==1){ /*parallel to beamline*/<br>
/*returns a negative distance so know that it was not
calculated*/ <br>
return;<br>
}</font><br>
<br>
In this case beamline is not used, this is a regurgitated function
used for another program that calculates the vertex of a particles
from the beamline if # of tracks ==1, otherwise all tracks in TBTR.<br>
<br>
I will provide plots tomorrow, I wanted to give a heads up about the
code, and why this might not be useful for either side of the
conversion debate.<br>
<br>
BR<br>
MK<br>
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