From: Steven Biller (s.biller1@physics.ox.ac.uk)
Date: Sat May 28 2005 - 19:09:39 CDT
Hi Mike,
Thanks for the new draft!
Here are a few (hopefully helpful) comments:
Side 1
======
Our "design goals" have certainly never centered around the value
of sin2(2theta) of 0.013 and I don't ever remember discussing the
required reach of a 90% CL (which, again, isn't stated here regarding
what you call "sensitivity" but should be). I think what is probably
the closest to what we ideally wanted at was a sensitivity at the level
of 3 standard deviations for a sin2(2theta) of 0.01.
At this point I feel I must again express my unease at separating
"discovery potential" from "sensitivity" and, indeed, even in that
choice of wording. Personally, I don't think a 90% CL means much
at all in this business and I don't think we should even risk giving
the impression that we'd settle for a 90% CL on anything by
highlighting it as some important goal. An upper bound on theta13 will
be just as important (argueably more so, if it turns out to be small)
as a measurement and we should apply the same rigid criteria to both.
Also, this experiment is not merely about a "discovery potential"
its about us being able to make a definitive and precise measurement
of a fundamental parameter. If, for example, it turns out that
Double-Chooz sees a 2.5 sigma or more effect before us, they may well
claim "discovery," but OUR experiment will then nail this beyond
all doubt and OUR precise determination will be the one used by
everyone in the community for years and years to come. I know other
proposed experiments may play with 90% CL intervals to sell their
project, but I think they just looks silly and think we would ultimately
look much better to our very learned reviewers if we made it clear up
front that our standards are higher and we're not looking for anything
short of 3 sigma, even for limit.
Slide 10
========
You need to spell out what you mean by "maximises data samples"
Slide 11
========
Same issues as with slide 1
Slide 20
========
This slide still does not work. Whatever words are said, the eye
is drawn to a figure which, on the face of it, shows a much more
dramatic effect for the 2-zone design and this is what sticks
in the mind. At the very least, a shaded region needs to be shown
where the energy shift is constrained to +-0.3%. Though, even this,
may draw some skeptcism about whether it can really be pinned
down to that level. On looking at this more, I definately think
a 'before' and 'after' plot would be MUCH better. In a short
presentation like this, I think it's important to leave the right
visual impressions that will stick around after the words have
faded.
Slide 25
========
You need to make it clear that your drawing is really just a
cartoon and does not necessarily represent how the shield will
actually look. Even aside from the fact that we're pursuing
alternative designs, you may get asked about things like
access to the neck, which is in your bullet points but not
in your sketches.
Slide 28
========
I think it's worth noting that you really do need both reasonable
depth and well-matched and well-understood overburdens at near and
far sites in order to do 12B to half a percent. That is, we should
strongly imply that only we can do this.... the others may well
claim that, of course, they can look at things like this as well,
but they won't be able to genuinely make use of it as a convincing
calibration of the relative fiducial volumes to the necessary level.
Slide 31 and, to a lesser extent, 32
====================================
You knew I was going to complain about this give my previous
tirade about 90% CL !
Slide 35
========
I don't believe it has been demonstrated, even in a "first analysis"
that ES systematics can be controlled to 1%. Questions have been
raised which may well be "show-stoppers" and these have not been fully
addressed, which is one of the points of having an ES review.
This phrase needs to either be dropped or substantially softened.
I would advocate the former.
Along a somewhat similar line, I would alter the highlighted box
to read, "Braidwood is unique among theta13 experiments in
HAVING THE POTENTIAL OF addressing this physics..."
Slide 38
========
Same gripe about "Sensitivity" vs "Discovery potential"
- Steve
This archive was generated by hypermail 2.1.6 : Wed Jun 01 2005 - 03:10:14 CDT