Re: BB vertex offset

From: Stephen J. Sanders (ssanders@ukans.edu)
Date: Mon Apr 16 2001 - 08:25:41 EDT

  • Next message: Flemming Videbaek: "Re: BB vertex offset"

    Hi Christian,  
    
    > 
    > On Thu, 12 Apr 2001 22:15:57 -0500
    > "Stephen J. Sanders" <ssanders@ukans.edu> wrote
    > concerning ": BB vertex offset":
    >> Hi,
    >> one significant difference in the two calculations to the approx. 2 cm
    >> difference found between the BB and TPM1 vertices.
    > 
    > Bjorn, Yury, do you know why there's this difference?
    > 
    > Steve, can we be absolutely sure that the BB vertex is "off" by 2 cm.?
    
    No, but this offset is strongly suggested by tracking the single mip
    peak in individual elements of the Si array as a function of vertex position
    and, talking to Hiro, the offset is needed to obtain a symmetric dN/deta
    distribution for the Si array.  At this point, I think a shift of the BB
    vertex is the most likely culprit.
    > 
    > 
    > Uh. Steve (and others) please don't use fabs, sin, cos, tan, and other
    > functions from cmath. Use TMath/BrMath instead. TMath is there to
    > insure portabliblity (various compilers have different ideas of
    > ANSI/ISO standard C - yes I know, stupid - ROOT doesn't).
    OK,  I was wondering why you didn't like to use the standard C/C++ routines.
    



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