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<div align="center"><font color="#000099"><b>Spin Structure of the
Deuteron<br>
New Results from CLAS<br>
<br>
Nevzat Guler<br>
(for CLAS Collaboration)<br>
ODU Physics Department</b></font><br>
<br>
February 18, 2010<br>
<br>
CEBAF Center F113<br>
11:00AM<br>
<br>
<u>Abstract</u><br>
<br>
Double spin asymmetries for the proton and the deuteron have been<br>
measured in the EG1b experiment using the CLAS detector at Jefferson<br>
Lab. Longitudinally polarized electrons at energies 1.6, 2.5, 4.2 and
5.7<br>
GeV were scattered from longitudinally polarized NH<sub>3</sub> and ND<sub>3</sub>
targets.<br>
The double spin asymmetry <i>A</i><sub>11</sub> has been extracted
from these data as a<br>
function of <i>Q<sup>2</sup></i> and <i>W</i> with unprecedented
precision. The virtual photon<br>
asymmetry <i>A</i><sub>1</sub> and the spin structure function <i>g</i><sub>1</sub>
can be calculated from<br>
these measurements by using parameterizations to the world data for the<br>
virtual photon asymmetry <i>A</i><sub>2</sub> and the unpolarized
structure functions<br>
<i>F</i><sub>1</sub> and <i>R</i>. The large kinematic coverage of the
experiment (0.05 GeV<sup>2</sup><br>
< Q<sup>2</sup> < 5.0 GeV<sup>2</sup> and 1.08 GeV < W <
3.0 GeV) helps us to better<br>
understand the spin structure of the nucleon, especially in the
transition<br>
region between hadronic and quark-gluon degrees of freedom. The results<br>
from EG1b combined with other experiments provide a good description of<br>
the virtual photon asymmetries making their parameterizations possible<br>
in a large kinematic range. In this talk, the results on <i>A</i><sub>1</sub>,
<i>g</i><sub>1</sub> and the first<br>
moment D<sub>1</sub><sup>1</sup> of the deuteron will be presented. The
parametrization efforts<br>
on the asymmetries and the spin structure functions will be discussed.
The<br>
neutron spin structure function, extracted from the combined proton and<br>
deuteron data, will be shown.</div>
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