Re: BBRdo Questions...

From: Yury Blyakhman (Yury_B@physics.nyu.edu)
Date: Thu Nov 09 2000 - 09:50:59 EST

  • Next message: Yury Blyakhman: "BB Vertex."

    	Hello, everybody.
     Ian, thanks for noticing the bug, I'll fix it.
    As for the timing question, in general I'm working now on improving it
    in general and creating smth. like a quality factor to go with t0. In
    other words, when ever you ask BBRdoModule for t0, it'll tell yo how
    good it is at the same time. But this is well in future because of many
    other things on the to-do-NOW!!! list...
     The simplest solution I can suggest would be to individually modify
    BBRdo Module. As of now it determines t0 using all of the tubes, but it
    uses different mechanism for Small and Big tubes. One'll just have to
    comment out lines about Small tubes, starting with smth like:
      if(l<37)...  and  if(r<31)
    l and r are indices for Left and Right and Small numbers are: l=1...36
    and r=1...30.
     As of now, if it can't extract time from any of the tubes using "good"
    method, it uses the "fastest tubes". It's resolution is also of the
    order of 4cm and "fastest" mechanism is used roughly in 5-10% of the
    events. So, if one wants to use Big tubes only, one'd have to comment
    this part as well.
    
     As for dN/dEta, Flemming answered it already. i'm looking into ALL
    possible reasons... Thanks,
    
    "I. G. Bearden" wrote:
    > 
    > Dear Dev-iants,
    > I have been looking a little at the BBRdoModule to try to figure out how
    > to use
    > only the Big tubes to produce T0, since these apparently have the best
    > resolution.
    > Yury, I think you have done this before, how?
    > Also, is it reasonable to have two T0s in the rdo data object, say one
    > from the
    > whole BB array and one from only the Big Tubes?
    > I think I also found a bug in the code....
    > in the loop over the "left" side of the array, the following line
    > appears:
    >     rdodata->SetLeftHits(NumLeft);
    > and in the loop over the "right" side, the following appears:
    >      rdodata->SetLeftHits(NumRight);
    > I guess this is not right.  I think that I have the latest version, but
    > if not, sorry
    > for the false alarm.
    > 
    > I have one other question related to the Beam-Beam results from Yury's
    > last note.
    > The multiplicity appears to be higher on the right side (i.e. positive
    > eta), is this
    > due to scattering from D1?  If so, how much--if at all--do the results
    > change with the
    > angle of the FS?
    > Cheers,
    > 
    > --
    > Ian--------------------------------------------------------------------
    > | I.G. Bearden                                                         |
    > | Niels Bohr Institute Tb 3    email:      bearden@nbi.dk              |
    > | Blegdamsvej 17               phone:      (+45) 35 32 53 23           |
    > | København Ø                    FAX:      (+45) 31 42 10 16           |
    > | Danmark                                                              |
    >  ----------------------------------------------------------------------
    
    -- 
            Yury Blyakhman.                               
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