PAC24 Presentation Tuesday June 17, 2003 see:
Related Experiments see: http://www.jlab.org/exp_prog/experiments/
E03-110 Jlab-Technical-Review and Jlab Theory Review (Below)
Proposal Number: P03-110Hall: C
Days requested for approval: 5 days
Tune up included in beam line request: no
Energy: 1.18, 2.29, 3.41, 4.52, 5.64, GeV and 1.64, 4.04 GeV
Current: 30 - 80 m A
Nuclei: 4 cm LH2, LD2, A1(MT), C, Fe, Cu, Au, Si, Ca, Quartz, (possibly H 20)
HMS: single arm mode
SOS: single arm mode
Special requirements/requests: none
1) The experiment is technically doable, as proven by the previous E94-110 experiment, a similar measurement on the proton. In addition, experiment E99-118 has performed similar measurements on nuclear targets in the region of W2 ~ 5 GeV2, with far worse particle identification, charge symmetric background, and radiative correction problems.
2) The experiment is an add-on to approved experiment E02-109 that performs similar measurements on a deuterium (and A1 dummy) target. No overhead, apart from target changes, is included in this experiment, as it is assumed that the additional targets can be added either to the cryogenic target ladder, or to a standalone nuclear target ladder.
3) If the experiment would be scheduled separately from E02-109, the overhead for this experiment would amount to an additional 5-6 days, not requested, including one energy change and five pass changes.
4) As this is an L/T separation, many beam pass changes are required, and an additional one (major) linac energy change. However, as mentioned, these energy changes are compatible with the previously approved E02-109.
5) The experiment assumes some unconventional targets such as Si, Ca, and Quartz, and further more mentions it will investigate adding a water target.The choice of these targets is guided by targets/detectors used in neutrino physics experiments. Although none of these targets are impossible, some care would need to be taken.E.g., the final current allowed by some of these depends strongly on the thermal contact with external active or passive cooling (as also mentioned in the proposal), the Ca target should be kept in oil as it reacts with air (such a target has been used before in Hall C), and possible inclusion of a water target seems non-trivial.
6) The estimated uncertainty in D RA is not given, but is presumably similar as the estimate of D RD of E02-109: 0.03-0.05.To reach such precision in an experiment accessing a wide range of rates in the detectors is difficult, although conditions are easier than in E99-118.The achieved uncertainty of E99-118 should be shown.
7) The experiment does include some overhead for investigation of charge symmetric backgrounds and radiative corrections.
From PAC24 Home Page:
Questions from Kuhn
Answers at: http://www.pas.rochester.edu/~bodek/jlab/PACcomments.htm
as you know, I am the secondary reader for your new PAC proposal 03-110.
Since time is getting short for your preparation for the PAC meeting,
preliminary questions/concerns I have about your proposal. If you want to meet in person to discuss these issues, I should be available sometime next week.
However, I would also appreciate an email response.
1) Obviously, this proposal is related to similar experiments already
approved or even completed. In particular, some results from 99-118
and how they relate to the proposed program would be interesting. Is
there any overlap (or could there be) with PR03-103? (J. Arrington,
2) In a similar vein, could you address the question "what do we learn
from this wide variety of nuclear targets (some quite unconventional,
for sure) that we cannot learn from a careful comparison of just
a few 'pure' species, e.g. C, Al and maybe Fe?" My naive assumption
would be that R_A is approximately equal to R_D (plus Fermi smearing),
and if there is an EMC-type effect, it should be quantifiable by studying
a few denser/heavier nuclei. I'm worried about the overhead of all
these target changes.
3) In general, I believe it would be good to have a clear and detailed
expose of the INTRINSIC Physics value of your proposed measurements
(what will we learn about nuclei, QCD, nuclear corrections, the
EMC effect... that we don't know already) as opposed to just the
neutrino-related justification. Can you show us a comparison of
the expected data (with statistical and systematic errors) on a plot
like Fig. 1? Maybe even with expected error bars from 99-118?
4) Regarding the Al target: Do I read your table II correctly that seems
to say that you'll spend a lot more time on Al than all other target
types? I realize this is part of E02-109, but couldn't one shorten
this time by using thicker Al targets?
5) I also would like to get a clearer idea of the value of the proposed
data in relationship to the neutrino experiments. Do you need the
measured R values as INPUT to analyze nu experiment? In that case,
can you show the impact of these proposed data on nu data (how much
does their systematic error due to lack of knowledge of R shrink)?
Or do you argue that these data can be COMPARED with nu ones? In that
case, can you give us an idea of what this comparison would look like (what
quantities can one extract or tests apply? With what confidence level?)
Greetings - Sebastian
Date: Tue, 10 Jun 2003 12:36:32 -0400
From: Sebastian Kuhn <email@example.com>
To: Cynthia Keppel <firstname.lastname@example.org>
Cc: F. Klein <email@example.com>
Subject: Re: response to PAC reader questions
Hi Thia (and Arie),
thanks for your very detailed answers to my questions. I will ponder them
some more and look at the updated version of your proposal. Unfortunately,
it may be
hard to get together to discuss these issues in person before the PAC meeting due to all the other events going on this week (which I am heavily involved in).
However, I'll be certain to try to contact one of you if there are remaining questions after your presentation.
I had a quick look at some of your slides. I guess (to reiterate my main
points) what I really would like to see are "predicted pseudo-data" together
existing (preliminary) results from SLAC and JLab, including 99-118. I realize that the kinematic region is different, but it is much easier to visualize the
impact these new data would have if they could be plotted vs. some reasonable model predictions for R (maybe even several) in nuclei. Correspondingly, it
would also be nice to see a plot of some quantities extracted from neutrino scattering (e.g. sum rules, moments, duality tests,...) with the systematic error that one
would get WITH and WITHOUT the knowledge these new data will provide. I realize that all of this hangs together and each piece of information
is valuable (for better models etc.), but it's always better to be quantitative (or at least illustrative).