From FRASCATI@axcdfq.fnal.gov Mon Apr  9 19:05:51 2001
Date: Fri, 23 Mar 2001 16:19:56 -0600
From: FRASCATI@axcdfq.fnal.gov
To: velev@fnal.gov, v0565@fnal.gov, rebcdf@fnal.gov, goshaw@fnal.gov,
     bed@fnal.gov, rlc@fnal.gov
Subject: 5450 q&a

From:	SMTP%"rlc@fnal.gov" 20-MAR-2001 18:02:10.80
To:	FRASCATI
CC:
Subj:	Re: comments on cdf 5450

     dear cdf 5450 godparents,
     I don't agree that most of my questions have been answered
     in a satisfactory way. A few examples:

 1) the gamma+b  analysis compares data to a method II prediction
    of the SM background. This prediction has an error of about 16%,
    close to the error of the method II prediction of the background
    to W+b events. I was impressed and I wanted more details on how each
    background and its
    uncertainty were estimated. I also thought that, before claiming such an
    accuracy on the background calculation, the authors should have shown
    that they understand the same backgrounds in other data samples.
    This is standard practice in a ``conservative and careful" collaboration.
    There is nothing like this in the answers:
    a)  I am not  told
    how the rate of negative tag was parametrized.
    b) there is no way
    of understanding in the paper or in the documentation how
    the rate of fake photons  is determined
    c) the authors believe that they tag jets correctly, but a
    tautological answer is not good enough. Good answers are
    "Weiming checked it" or " here is the list of tags, check it".
    d) I am glad to know that Keith (who should then be referenced
       in the PRD) and not MLM calculated the
      matrix element of gamma b production.
     Nevertheless, I would like to
     see some description of its implementation into Herwig
     (and some checks too). I remain
     that the uncertainty of the calculation  is not
     discussed seriously (remember that the Ellis calculation
     of the bbar production is off by a factor of two).

2)   I thought that showing a comparison of data and prediction up to
     a jet multiplicity of 8 was silly. Your answer:
     "The higher jet multiplicities would be predicted by the standard
      Herwig; they were not specifically checked."

3)  There is no point in showing Figure 33 with ``a posteriori probabilities".
    The problem is not the ``a posteriori" as you seem to suggest, but the
    fact that a reliable background calculation is missing. You say
    this innn the text, but a confession is not an absolution.
    In addition, one is not
    supposed to sin and repent in the same article.

4) There is no point in showing double tags without an evaluation
   of the background

5) There is no point in singling out events by run and number when there
   is no solid background estimate or no excess.

 I understand that, since there is not a SUSY discovery, the attitude is
 very cavalier and errors and procedures are let to be handwaved.
 It makes no harm here, but helps diffusing
 in the scientific community the perception  that we are a conservative but
 not careful collaboration. On one side, I find it regretful that you are
 sacrifying  an interesting QCD measurement to the SUSY hype.
 On the other hand,
 imagine that actually CDF (or D0) will
 find out in Run II that the all calculation is wrong
 by a factor of two and there is actually a huge excess. How will you feel
 having set a 16% error now?
 In addition, all this showing of events with MET and double tags will
 backfire  when taken
 out of the context of the  determination of the background,
 where they belong.

 regards, Paolo