[Clas12_rgb] new RG-B wiki page, news, and plans

[Silvia Niccolai]

Dear RG-B collegues,
I am preparing a new Run-Group B wiki page, which will be our page of 
reference for all information of the incoming experiment.
The link is: 
https://clasweb.jlab.org/wiki/index.php/Run_Group_B

It is also accessible from the main CLAS12 wiki (https://clasweb.jlab.org/wiki/index.php/Main_Page )

As you can see, it is still mainly empty, aside from the Software and 
Calibration sessions, where I listed the manpower available for the 
different tasks, based upon our internal discussions and the outcomes of 
the CLAS12 Task List.

There has been a meeting, last week, to start a transfer of 
information, mailny about about monitoring and reconstruction software 
between RG-A and RG-B. I included in the wiki the slides that Raffaella 
showed to introduce the subject. Following that first meeting, other 
"RGA->RGB training meetings" are taking place, in JLab, in these days.
I encourage the people who are attending these meetings (Zhiwen and 
Katheryne, mainly), to please update the wiki (section "Software") with 
as much information as they can put together from these "training" 
session.

I am going to contact all people who volounteered as calibrators for RGB 
to ask them to get some training, using RGA/RGK data and under the 
supervision of the detector experts, so to be ready to calibrate RG-B data 
as soon as they start coming in. We already had one such "training" 
session for the CND, and it was quite useful, I believe.

I propose to start having weekly RGB meetings (maybe starting from after 
Christmas) to get ready for the experiment. Would every Thursday at 8AM 
(or 8:30?) US time be OK more of less for everybody? Please respond to me 
privately to avoid email overload. We could start on January 10th.

Among the issues that we should discuss in our next meeting is the one 
about taking proton data. My post-doc has been analyzing RGA data (at 10.6 
and 6 GeV) to study the CND efficiency for neutrons via the ep->epi+X channel. 
He got nice results (and consistent with expectations and simulations) 
with the 6-GeV data, for which the missing-neutron peak is clearly visible 
and the background low and easy to separate. On the other hand, he could 
not get any decent clean-neutron events out of the 10.6-GeV data, due to 
the high background in the missing mass distribution.
We should make sure that 10.6 GeV data can be used to properly measure 
neutron efficiency. Otherwise, it would make more sense to spend the whole 
RGB spring run on deuterium target, and use RGK data, which are taken at 
low beam energy, to monitor the neutron efficiency.

We also need to discuss about the trigger configuration and choice of beam 
current.

Looking forward to your replies.

Best regards,
Silvia