2 D parity violating proposal
Spokeperson X Zheng


Preliminary Review

Alas this proposal is very hard to read.  Both because of its organization, 
and the inadequate use of the English language.
Time does not permit me to go over these in detail.

I think that I have got the points clear in my mind but am not sure.   This 
review has two parts:
The physics itself\

The proposal
It may seem unimportant but whoever is accepting or rejecting the proposal 
has to understand it and be sure he has missed nothing of importance.  As 
it is written that is hard.
I suspect that it is too late to do a major reorganization of the proposal 
so I suggest some cosmetic features.

Someone whose native language and education is in English should go over it 
and get tenses, prepositions and pronouns straight.
Equipment in existences WAS built and IS now.  Equipment to be built WILL 
be built.  There is a difference between WILL and SHALL.  One leanrs:  "If 
a drowning man says I WILL die and no one SHALL save me, someone might take 
him at his word and let him die.  But if he cries:  I SHALL die if no one 
WILL save me that is a different matter."   I found two places where this 
was (I hope) misused.  I say I hope, because we hope someone WILL build the 
equipment and it SHALL be ready..

The abstract is long and does not carefully summarize the crucial 
points.  It is important because a casual reader may think that the 
proposers dont know what is crucial.   Let me see whether I have the 
crucial points right.   If I have not, then I suggest that the fault is 
that of the proposers.  (the old adage - the customer is always right)

1.  Scattering is described by a set of coupling constants of which the 
group (2C2u - C2d) is poorly measured.
2.  Although the standard model describes them all in terms of one 
parameter sin^2 thetaW , it is important to check these in detail to see 
whether there are small differences which might suggest new physics beyond 
the standard model
  3.  We propose to measure this quantity with an improved precision of a 
factor of eight.
4.  A complication is higher twist effects which we will check by 
measurements at two different values of Q^2
5.  We propose to do the experiment in HALL A and use the experience, and 
much of the apparatus, of previous parity violation experiments in HALLA.
6.  The following improvements and changes are necessary.
(i) A beam of 85 microamp on a liquid D2 target - hopefully to be soon 
demonstrated with an  approprate raster
(ii) measurement of polarization to an accuracy of 1% - both by Compton 
Polarimetry and Moller.  This to be done already in the forthcoming neutron 
radius experiment
(iii) counting not integrating because of pion background.

The motivation seems good.  One of the goals of many experimenters is to 
test the standard model in all conceivable ways.   This will, of course, be 
done at CERN starting in about 4 years, but  preliminary indications are 
well worthwhile.   What are unclear are:
(A) whether anyone else is doing it
(B)  Whether anyone else can do it better by the time (alas, all too long) 
this experiment can run.
(C)  whether CERN running might make this experiment irrelevant.

The team is the experienced HALL A parity team plus  a few more (this might 
well be emohasized for the ultimate reviewer) and provided there is a clear 
answer to the above three questions the    approval should be forthcoming.