[Clas_cascades] simulation time problem?

[Zhiwen Zhao]

Hi, All

http://clasweb.jlab.org/rungroups/eg3/wiki/index.php/Eg3_simulation
I add more plots and description, particular the plots use vertex time 
calculated without vertex term.

I still think the time in SCPB is calibrated TOF time so it can be used in the 
formula without additional "starttime" mentioned by Stepan.

For data, the photon time in tagger is calibrated at target center, so to 
compare it to particle vertex time, the vertex term is needed. For sim, if I use 
photon time at target center, the vertex term is needed too. As shown in those 
plots,the vertex term will make peak sharper and nicer for data and sim.

The main problem I have now is the time diff is not centered around 0 for sim, I 
will need photon time = (-56)/c_light to make that happen( please refer to the 
plots). This makes me wonder either some of my understanding is wrong or my 
simulation configuration is wrong.

Please comment.

Thanks a lot

Zhiwen