Re: ZDC Vertex

From: Hironori Ito (hito@students.phsx.ukans.edu)
Date: Mon Mar 19 2001 - 13:31:10 EST

  • Next message: Michael Murray: "Re: ZDC Vertex"

    	Hello.   The figure includes any events which ZDC and TPM1 cluster
    vertex exist.  (I have to have TPM1 since that is what I am comparing 
    with.)  There is no additional cuts.  Unless the TPM1 cluster vertex has
    multiplicity dependence, which I have not heard such a dependence, it is coming
    from ZDC vertex.   Maybe, the slewing correction is not quite right???
    
    	Hiro
    
    On Mon, 19 Mar 2001, Michael Murray wrote:
    
    >   Dear Hiro,
    >           I guess that the figure was made only
    > for events in which the BB and the TPM1 vertex
    > failed. If so the effect you see could be induced
    > by an (multiplicity dependent)
    > inefficency in the vertex algorithm of 
    > these detectors. Could you please remake the
    > same plot for an unbiased sample of events from
    > the same run. Ideally that would be just ZDC triggers.
    >            Yours Michael
    > 
    > Quoting Hironori Ito <hito@students.phsx.ukans.edu>:
    > 
    > > 	Well.  I have another thought about fixing manually.  I can not
    > > fix manually since I only use ZDC vertex when I do not have good vertex
    > > from BB or TPM1.  This means that I can not fix ZDC since I do not have
    > > any other reference to fix ZDC Vertex.  
    > > 
    > >   hiro
    > > 
    > > On Fri, 16 Mar 2001, Hironori Ito wrote:
    > > 
    > > > 	Hello.  I have a question.  I remember reading the e-mail about
    > > > ZDC_Vertex do not have Multiplicity dependence.  Well, I think it is
    > > > there.  Look at the figure "ZDC_TPM1_vertex.ps" in
    > > > "http://pii3.brahms.bnl.gov/~hito".  The figure is produced from
    > > > run 2336.  In this figure, the vertical scale is
    > > > ZDC vertex - TPM1 (cluster) vertex, and the horizontal scale is BB
    > > > Mult.  Of cause, it is possible that BB Mult is wrong.  But, if I use
    > > > other mult such as Si and Tile mult, I see the same thing. 
    > > Furthermore, I
    > > > do not see this much dependence from BBVertex - TPM1 Vertex although
    > > > BBVertex have other problem.  Can someone look at this?  The fix is
    > > > needed since multiplicity in Si can easily is affected by 3-4 cm shift
    > > of
    > > > vertex.  Until it is fixed, I will manually (in my own code) fix
    > > ZDCVertex
    > > > to align to TPM1 vertex.  
    > > > 
    > > > 	Hiro
    > > > 
    > > > 
    > > 
    > 
    > 
    > 
    > Michael Murray, Cyclotron TAMU, 979 845 1411 x 273, Fax 1899
    > 
    



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