From evans@nevis1.nevis.columbia.edu Fri Aug  7 03:01:04 1998
Date: Fri, 7 Aug 1998 09:31:18 -0400
From: Hal Evans <evans@nevis1.nevis.columbia.edu>
To: Horst Wahl <wahl@fsheb2>
Cc: Hal Evans <evans@nevis1.nevis.columbia.edu>
Subject: comments on Physics Section
Resent-Date: Fri, 7 Aug 1998 9:32:55 -0400 (EDT)
Resent-From: wahl@FSHEB1
Resent-To: wahl

Hi Horst,

I looked over your draft of the physics section of the report to
the PAC. It looks quite good - and addresses all the points I think
we should be making.

I have a few suggestions for improvements - but they are mainly
cosmetic. If you don't think that any of them would be useful,
don't bother putting them in.

*** Section 1.2.2 (page 2):
- phi0 should be defined for b<>0. You could add something like:
  "... B is the impact parameter [and phi0 is phi at the point
   of closest approach of the track to the nominal beam line.]"
- It might also be worthwhile mentioning that phi(r) is an
  approximation and point out under what conditions it holds.

*** Et/Pt for electrons at L2 (page 4):
- Was 13%/sqrt(E) used as the L2 electron energy resolution as in
  Fig. 13? (This seems quite good to me for a L2 number, by the way).
  It should probably be stated.

*** Section 1.3 (page 5)
- Would it be worth adding to the list of benefits of the STT that it
  could provide stability against unforseen backgrounds? In the case
  where background conditions are significantly worse than predicted
  the signal to background behavior of STT triggers could decrease less
  sharply than normal triggers. I think that this is the reason why
  John's WH0 studies have more optimistic conclusions than Doug's
  SUGRA 4-b results. Doug only looks at points of high signal efficiency
  and low backgrounds - while John considers a broader eff/bgrd set.

Section 1.6 (page 9)
- If I remember correctly, the current Higgs limit from LEP as reported
  at ICHEP 98 is something like 89 GeV (rather than 75 from last year).
  Another study of the final LEP reach has also been done (and was
  presented at ICHEP). It indicates that the final LEP Higgs reach will
  be around 105 GeV.

Table 5 (page 11)
- What does TT mean? Is it the number of tracks with Pt>X? If so, perhaps
  it should be called Trks.

Section 1.8 (page 13)
- We should probably use l+l- instead of mu+mu- in the rare decay mode
  list to be as general as possible.

***** Table 11 (page 15)
- Where do the background cross-section and eff1 come from? It might
  be clearer to quote the total background cross-section and eff1 from
  the trigger rejection factor, if this is possible.

Reference 26 (page 19)
- Refer to ICHEP 98 talks. Peter Macnamara gave the LEP Higgs talk and
  Daniel Treille gave the searches summary.

Figure 13 caption (page 23)
- "...z-vertex [assumed to be] at zero..."

That's all for my comments. I hope that they're useful. As I 
mentioned before, I'll be out of contact for the next two weeks. I'll 
return on the 24th of August.

Best Regards  -  Hal

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