i have performed a separate analysis on the polarized hydrogen data taken
in the past day (i.e. runs 1846-1848, 1850-1852, 1854, 1855, 1860-1863).
due to the miscabling error discovered yesterday, i believe that only
this data is reliable. i cannot find the theoretical pictures that
vitaliy claimed to have found. the data is these plots had charge and
coplanarity cuts imposed on them.
i don't believe my results. i do not know what the theory says, but this
picture looks too high, considering that both the helicity and the vector
polarization are still included in these plots. maybe there's an error in
the macro. or else blast has problems.
to do this analysis, i wrote a new macro called "show_ep_asym2.C"
("show_ep_asym.C" is a pre-existing but currently non-working macro.) the
macro is fairly easy to adapt. it is also well documented.
i am leaving for a while later on in this week. thus, someone else should
probably take over the hydrogen asymmetry analysis, as it will surely go
on for a while longer.
if you care (or are forced) to pick up where i am leaving off, you need to
know the following:
1) for each run, you need to go to the pro2003/analysis/CRUNCH/v3/
directory and run the "lrn" macro, then you need to go to the
pro2003/analysis/utils/ directory and run the "flrn.C" macro, and then
you need to go to the pro2003/analysis/macros/ directory and run the
"charge.C" macro. do NOT run the "charge_t20.C" macro (as we have been
doing for the past two months or so).
2) the next step is to go to the pro2003/analysis/utils/ directory and
look at the "strings.C" file. make sure that it is set up for proton
scattering off of a hydrogen target!!!! (this is extremely simple to\
do if you just read the documentation at the beginning of the
"strings.C" file.)
3) you can then run the "show_ep_asym2.C" macro. for example, to
calculate the asymmetry in runs 1846-1848, 1850-1852, 1854, 1855, and
1860-1863, type the following:
root -l show_ep_asym2.C 1846-1848 1850-1852 1854 1855 1860-1863
4) i'm not very experienced with hydrogen analysis. the "show_ep_asym2.C"
macro assumes that the H(e,e'p) cross section is given by the
following:
S( h, P) = S0*(1 + h*P*A_{eN})
thus:
h*P*A_{eN} = [S( h, P) - S(-h, P)] / [[S( h, P) + S(-h, P)]
if this assumption is wrong, the macro is straightforward to modify.
5) a VERY GOOD check to run on your hydrogen data is to run the
"show_ep_asym2.C" macro only for runs of ONE DEFINITE POLARIZATION
STATE (i.e. (h = +1, P = +1) or (h = -1, P = +1)). the first few lines
that the macro prints out tell how much charge was collected in each
polarization state. the next few lines tell how many hits were
collected in each each polarization state. check that charge and hits
were collected in only the polarization state pertinent to the runs.
this may sound like a funny check, but this error has appeared numerous
times in the last couple of months (it even occurred this morning).
good luck.
aaron
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