[Clas_lmd] The g11 data with tracking matrices is available

[Sudeep Ghosh]

Greetings to Everyone,

        Finally we have the g11 data available with tracking matrices at
"/mss/clas/g11a/production/pass1/v1/ntuple/" in ".hbook" format.
We also need to follow instructions below given by Raffaella
before converting it to ".root" and using the PID for event
selection.

        In using this ntuples for the analysis, one should consider that
the particle selection in the EVNT (SEB) common blocks is rather
loose and additional cuts should be always applied. Listed below
are some of the typical cuts used in the analysis (these are a
reasonable example but adjustment may be needed depending on the
specific analysis) referring to the variable names in the ntuples
and assuming vector indexes start from 1 as it is in fortran.

charged particles:
- dc(i)>0  : ensure track information is available
- stat(i)>0: ensure information from the different detector is consistent
- may need to cut on m(i) for kaons or on their vertex time
- dc_stat(dc(i))>0 : require time-based tracking; dc_stat(dc(i)) is the
pointer to the tbtr and tber banks for the i-th particle that may be
needed for the kinematic fit

general cuts on incoming photon:
- taggoodhit>0 : at least one good photon in the tagger
- abs(dt_st_tag(1))<1. : difference between start counter and tagger time
for the best matching photon is less than 1 ns.

      To implement these, we need assistance from someone who has the
experience of working on G11.

Best regards,
-- 
Sudeep Ghosh
Research Scholar
LMD-CAA Collaboration
IIT Indore, India