[Sane-analysis] DNP abstract (again)

[Whitney R. Armstrong]

Thanks for your comments. I see that there was some cyber attack or
something... I could not ssh the lab. Anyway...

Here is an updated version.

The Spin Asymmetries of the Nucleon Experiment (SANE) measured the virtual
Compton scattering asymmetries, $A_1$ and $A_2$, which allows for a direct
measurement of the spin structure functions of the proton,  $g_1$ and $g_2$.
The kinematics for these measurements are in a range of Bjorken $x$, $0.3 <
x < 0.8$, where extraction of the twist three matrix element $d_2^p $ (an
integral with respect to $x$ of $2g_1+ 3g_2$ weighted by $x^2$) is most
sensitive. The observable, $d_2$, is a measure of the average restoring
Lorentz color force experienced by a quark inside a polarized nucleon after
it is struck by a virtual photon in electron Deep Inelastic Scattering
(DIS)[1]. The data was taken at the Thomas Jefferson  National Accelerator
Facility's Hall C, using beam energies of $4.7$ and $5.9~GeV$, probing the
nucleon at scales ranging from $Q^2 = 2.5~GeV^2$ up to $Q^2 = 6.5~GeV^2$.
In this polarized electron scattering off a polarized proton target
experiment two inclusive double spin asymmetries, $A_\parallel$ and $A_{80}$
($\simeq A_\perp$) were measured using the BETA (Big Electron Telescope
Array) detector. BETA is a device without magnetic momentum dispersion that
consists of a front scintillator hodoscope followed by a threshold gas
Cherenkov counter, a Lucite hodoscope and a large array of lead glass
detectors. In addition to motivating the physics of the proton's spin
structure we shall discuss the analysis of the BETA data and present
preliminary results.

[1] M. Burkardt, AIP Conf. Proc. 1149, 62 (2009) [arXiv:0902.0163 [hep-ph]].

On Fri, Jul 1, 2011 at 2:02 PM, O. A. Rondon <or at virginia.edu> wrote:

> Hi Whit,
>
> Most group members probably did not get your first message. I think
> there was a problem with JLab e-mail last night.
>
> The abstract looks good. One comment would be that since g1 and g2 can
> also be measured directly, I suggest wording it so it does not sound
> like one needs to measure A1 and A2 first, it is just how we did it. And
> what we actually measured are A_para and A_80.
>
> There is also a reference [1] in the text that is not shown at the end.
> Probably is should just be deleted.
>
> Cheers,
>
> Oscar
>
>
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