https://halldweb.jlab.org/wiki/index.php?title=07/07/2020&feed=atom&action=history07/07/2020 - Revision history2024-03-29T10:31:04ZRevision history for this page on the wikiMediaWiki 1.24.1https://halldweb.jlab.org/wiki/index.php?title=07/07/2020&diff=100121&oldid=prevDeurpam at 14:55, 8 July 20202020-07-08T14:55:28Z<p></p>
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<tr><td class='diff-marker'> </td><td style="background-color: #f9f9f9; color: #333333; font-size: 88%; border-style: solid; border-width: 1px 1px 1px 4px; border-radius: 0.33em; border-color: #e6e6e6; vertical-align: top; white-space: pre-wrap;"><div>General:</div></td><td class='diff-marker'> </td><td style="background-color: #f9f9f9; color: #333333; font-size: 88%; border-style: solid; border-width: 1px 1px 1px 4px; border-radius: 0.33em; border-color: #e6e6e6; vertical-align: top; white-space: pre-wrap;"><div>General:</div></td></tr>
<tr><td class='diff-marker'> </td><td style="background-color: #f9f9f9; color: #333333; font-size: 88%; border-style: solid; border-width: 1px 1px 1px 4px; border-radius: 0.33em; border-color: #e6e6e6; vertical-align: top; white-space: pre-wrap;"></td><td class='diff-marker'> </td><td style="background-color: #f9f9f9; color: #333333; font-size: 88%; border-style: solid; border-width: 1px 1px 1px 4px; border-radius: 0.33em; border-color: #e6e6e6; vertical-align: top; white-space: pre-wrap;"></td></tr>
<tr><td class='diff-marker'>−</td><td style="color:black; font-size: 88%; border-style: solid; border-width: 1px 1px 1px 4px; border-radius: 0.33em; border-color: #ffe49c; vertical-align: top; white-space: pre-wrap;"><div>M.D:</div></td><td class='diff-marker'>+</td><td style="color:black; font-size: 88%; border-style: solid; border-width: 1px 1px 1px 4px; border-radius: 0.33em; border-color: #a3d3ff; vertical-align: top; white-space: pre-wrap;"><div><ins class="diffchange diffchange-inline"><!--</ins>M.D:<ins class="diffchange diffchange-inline">--></ins></div></td></tr>
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<tr><td class='diff-marker'> </td><td style="background-color: #f9f9f9; color: #333333; font-size: 88%; border-style: solid; border-width: 1px 1px 1px 4px; border-radius: 0.33em; border-color: #e6e6e6; vertical-align: top; white-space: pre-wrap;"><div>S.Š: (By email):  </div></td><td class='diff-marker'> </td><td style="background-color: #f9f9f9; color: #333333; font-size: 88%; border-style: solid; border-width: 1px 1px 1px 4px; border-radius: 0.33em; border-color: #e6e6e6; vertical-align: top; white-space: pre-wrap;"><div>S.Š: (By email):  </div></td></tr>
</table>Deurpamhttps://halldweb.jlab.org/wiki/index.php?title=07/07/2020&diff=100120&oldid=prevDeurpam at 14:54, 8 July 20202020-07-08T14:54:52Z<p></p>
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<tr><td class='diff-marker'> </td><td style="background-color: #f9f9f9; color: #333333; font-size: 88%; border-style: solid; border-width: 1px 1px 1px 4px; border-radius: 0.33em; border-color: #e6e6e6; vertical-align: top; white-space: pre-wrap;"></td><td class='diff-marker'> </td><td style="background-color: #f9f9f9; color: #333333; font-size: 88%; border-style: solid; border-width: 1px 1px 1px 4px; border-radius: 0.33em; border-color: #e6e6e6; vertical-align: top; white-space: pre-wrap;"></td></tr>
<tr><td class='diff-marker'> </td><td style="background-color: #f9f9f9; color: #333333; font-size: 88%; border-style: solid; border-width: 1px 1px 1px 4px; border-radius: 0.33em; border-color: #e6e6e6; vertical-align: top; white-space: pre-wrap;"><div>A. D.:  </div></td><td class='diff-marker'> </td><td style="background-color: #f9f9f9; color: #333333; font-size: 88%; border-style: solid; border-width: 1px 1px 1px 4px; border-radius: 0.33em; border-color: #e6e6e6; vertical-align: top; white-space: pre-wrap;"><div>A. D.:  </div></td></tr>
<tr><td class='diff-marker'>−</td><td style="color:black; font-size: 88%; border-style: solid; border-width: 1px 1px 1px 4px; border-radius: 0.33em; border-color: #ffe49c; vertical-align: top; white-space: pre-wrap;"><div>*Remembered why so far the GDH data on neutron have not been published in spite of the available deuteron data from MAMI/ELSA. This is because of the very large contribution from deuteron 2-body breakup at very low nu. With the 1/nu weighting, the 2-body breakup cancels almost exactly the resonance+large nu part. Accurately correcting for it to get the neutron information is very delicate without a very good model of the deuteron structure, see  [https://arxiv.org/abs/nucl-th/0006083 the study by H. Arenhövel] concluding that "''It is very doubtful, if not impossible, that one can extract in a simple manner the neutron spin asymmetry from the spin asymmetry of the deuteron.''" [https://arxiv.org/abs/nucl-th/0407058 A later paper] confirms this stating "''This means that a direct experimental access to the neutron spin asymme- try from a measurement of the spin asymmetry of the deuteron by subtracting the one of the free proton is not possible. On the other hand, polarization data of me- son production on the deuteron certainly will provide a more detailed test of meson production on the neutron and thus, in an indirect manner, on its spin asymmetry.''" This is a problem for the MAMI/ELSA data, but less for us because at large nu, the problematic contribution from the 2-body breakup is gone. Therefore, our extraction of the neutron information will be reliable, and consequently:</div></td><td class='diff-marker'>+</td><td style="color:black; font-size: 88%; border-style: solid; border-width: 1px 1px 1px 4px; border-radius: 0.33em; border-color: #a3d3ff; vertical-align: top; white-space: pre-wrap;"><div>*Remembered why so far the GDH data on neutron have not been published in spite of the available deuteron data from MAMI/ELSA. This is because of the very large contribution from deuteron 2-body breakup at very low nu. With the 1/nu weighting, the 2-body breakup cancels almost exactly the resonance+large nu part. Accurately correcting for it to get the neutron information is very delicate without a very good model of the deuteron structure, see  [https://arxiv.org/abs/nucl-th/0006083 the study by H. Arenhövel] concluding that "''It is very doubtful, if not impossible, that one can extract in a simple manner the neutron spin asymmetry from the spin asymmetry of the deuteron.''" [https://arxiv.org/abs/nucl-th/0407058 A later paper] confirms this<ins class="diffchange diffchange-inline">, </ins>stating "''This means that a direct experimental access to the neutron spin asymme- try from a measurement of the spin asymmetry of the deuteron by subtracting the one of the free proton is not possible. On the other hand, polarization data of me- son production on the deuteron certainly will provide a more detailed test of meson production on the neutron and thus, in an indirect manner, on its spin asymmetry.''" This is a problem for the MAMI/ELSA data, but less for us because at large nu, the problematic contribution from the 2-body breakup is gone. Therefore, our extraction of the neutron information will be reliable, and consequently:</div></td></tr>
<tr><td class='diff-marker'> </td><td style="background-color: #f9f9f9; color: #333333; font-size: 88%; border-style: solid; border-width: 1px 1px 1px 4px; border-radius: 0.33em; border-color: #e6e6e6; vertical-align: top; white-space: pre-wrap;"><div>** The short-term goal of the proposal (studying the sum convergence) is unaffected by the issue;   </div></td><td class='diff-marker'> </td><td style="background-color: #f9f9f9; color: #333333; font-size: 88%; border-style: solid; border-width: 1px 1px 1px 4px; border-radius: 0.33em; border-color: #e6e6e6; vertical-align: top; white-space: pre-wrap;"><div>** The short-term goal of the proposal (studying the sum convergence) is unaffected by the issue;   </div></td></tr>
<tr><td class='diff-marker'> </td><td style="background-color: #f9f9f9; color: #333333; font-size: 88%; border-style: solid; border-width: 1px 1px 1px 4px; border-radius: 0.33em; border-color: #e6e6e6; vertical-align: top; white-space: pre-wrap;"><div>** The longer term goal for the neutron (test of the GDH sum rule) is somewhat affected by the issue, but there are solutions:  </div></td><td class='diff-marker'> </td><td style="background-color: #f9f9f9; color: #333333; font-size: 88%; border-style: solid; border-width: 1px 1px 1px 4px; border-radius: 0.33em; border-color: #e6e6e6; vertical-align: top; white-space: pre-wrap;"><div>** The longer term goal for the neutron (test of the GDH sum rule) is somewhat affected by the issue, but there are solutions:  </div></td></tr>
<tr><td class='diff-marker'> </td><td style="background-color: #f9f9f9; color: #333333; font-size: 88%; border-style: solid; border-width: 1px 1px 1px 4px; border-radius: 0.33em; border-color: #e6e6e6; vertical-align: top; white-space: pre-wrap;"><div>***instead of complementing the possibly problematic MAMI/ELSA data, we can complement the JLab electroproduction data on neutron from 3He, extrapolated to Q=0 (the 3He data does not suffer from this problem). Since the electroproduction data are also limited to nu < 1.7 GeV (to compare to photoproduction: nu < 1.8 GeV) the point of the longer term goal remains.  </div></td><td class='diff-marker'> </td><td style="background-color: #f9f9f9; color: #333333; font-size: 88%; border-style: solid; border-width: 1px 1px 1px 4px; border-radius: 0.33em; border-color: #e6e6e6; vertical-align: top; white-space: pre-wrap;"><div>***instead of complementing the possibly problematic MAMI/ELSA data, we can complement the JLab electroproduction data on neutron from 3He, extrapolated to Q=0 (the 3He data does not suffer from this problem). Since the electroproduction data are also limited to nu < 1.7 GeV (to compare to photoproduction: nu < 1.8 GeV) the point of the longer term goal remains.  </div></td></tr>
<tr><td class='diff-marker'> </td><td style="background-color: #f9f9f9; color: #333333; font-size: 88%; border-style: solid; border-width: 1px 1px 1px 4px; border-radius: 0.33em; border-color: #e6e6e6; vertical-align: top; white-space: pre-wrap;"><div>***The development of models and expected data on the deuteron 2-body breakup from HIγS may solve the issue for the deuteron photoproduction data.</div></td><td class='diff-marker'> </td><td style="background-color: #f9f9f9; color: #333333; font-size: 88%; border-style: solid; border-width: 1px 1px 1px 4px; border-radius: 0.33em; border-color: #e6e6e6; vertical-align: top; white-space: pre-wrap;"><div>***The development of models and expected data on the deuteron 2-body breakup from HIγS may solve the issue for the deuteron photoproduction data.</div></td></tr>
<tr><td class='diff-marker'>−</td><td style="color:black; font-size: 88%; border-style: solid; border-width: 1px 1px 1px 4px; border-radius: 0.33em; border-color: #ffe49c; vertical-align: top; white-space: pre-wrap;"><div>*Got a message from Eugene regarding target polarization with spins anti-parallel to the solenoid B-field. Answered that it was possible to do, but with 1/2 the relation time of the parallel configuration. This is still 1400h so it is no issue for the short GDH run time.</div></td><td class='diff-marker'>+</td><td style="color:black; font-size: 88%; border-style: solid; border-width: 1px 1px 1px 4px; border-radius: 0.33em; border-color: #a3d3ff; vertical-align: top; white-space: pre-wrap;"><div>*Got a message from Eugene <ins class="diffchange diffchange-inline">C. (for TAC purpose?) </ins>regarding target polarization with spins anti-parallel to the solenoid B-field. Answered that it was possible to do, but with 1/2 the relation time of the parallel configuration. This is still 1400h<ins class="diffchange diffchange-inline">, </ins>so it is no issue for the short GDH run time.</div></td></tr>
</table>Deurpamhttps://halldweb.jlab.org/wiki/index.php?title=07/07/2020&diff=100118&oldid=prevDeurpam at 14:13, 8 July 20202020-07-08T14:13:42Z<p></p>
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<tr><td class='diff-marker'> </td><td style="background-color: #f9f9f9; color: #333333; font-size: 88%; border-style: solid; border-width: 1px 1px 1px 4px; border-radius: 0.33em; border-color: #e6e6e6; vertical-align: top; white-space: pre-wrap;"></td><td class='diff-marker'> </td><td style="background-color: #f9f9f9; color: #333333; font-size: 88%; border-style: solid; border-width: 1px 1px 1px 4px; border-radius: 0.33em; border-color: #e6e6e6; vertical-align: top; white-space: pre-wrap;"></td></tr>
<tr><td class='diff-marker'>−</td><td style="color:black; font-size: 88%; border-style: solid; border-width: 1px 1px 1px 4px; border-radius: 0.33em; border-color: #ffe49c; vertical-align: top; white-space: pre-wrap;"><div>J. S.:</div></td><td class='diff-marker'>+</td><td style="color:black; font-size: 88%; border-style: solid; border-width: 1px 1px 1px 4px; border-radius: 0.33em; border-color: #a3d3ff; vertical-align: top; white-space: pre-wrap;"><div>J. S.: <ins class="diffchange diffchange-inline">TAC reports are expected around July 20th.</ins></div></td></tr>
<tr><td class='diff-marker'> </td><td style="background-color: #f9f9f9; color: #333333; font-size: 88%; border-style: solid; border-width: 1px 1px 1px 4px; border-radius: 0.33em; border-color: #e6e6e6; vertical-align: top; white-space: pre-wrap;"></td><td class='diff-marker'> </td><td style="background-color: #f9f9f9; color: #333333; font-size: 88%; border-style: solid; border-width: 1px 1px 1px 4px; border-radius: 0.33em; border-color: #e6e6e6; vertical-align: top; white-space: pre-wrap;"></td></tr>
<tr><td class='diff-marker'> </td><td style="background-color: #f9f9f9; color: #333333; font-size: 88%; border-style: solid; border-width: 1px 1px 1px 4px; border-radius: 0.33em; border-color: #e6e6e6; vertical-align: top; white-space: pre-wrap;"><div>A. D.:  </div></td><td class='diff-marker'> </td><td style="background-color: #f9f9f9; color: #333333; font-size: 88%; border-style: solid; border-width: 1px 1px 1px 4px; border-radius: 0.33em; border-color: #e6e6e6; vertical-align: top; white-space: pre-wrap;"><div>A. D.:  </div></td></tr>
<tr><td class='diff-marker'>−</td><td style="color:black; font-size: 88%; border-style: solid; border-width: 1px 1px 1px 4px; border-radius: 0.33em; border-color: #ffe49c; vertical-align: top; white-space: pre-wrap;"><div>*Remembered why so far the GDH data on neutron have not been published in spite of the available deuteron data from MAMI/ELSA. This is because of the very large contribution from <del class="diffchange diffchange-inline">the </del>deuteron 2-body breakup at very low nu. With the 1/nu weighting, <del class="diffchange diffchange-inline">it </del>cancels almost exactly the resonance+large nu part <del class="diffchange diffchange-inline">and accurately </del>correcting for it to get the neutron information is very delicate without a very good model of the deuteron structure, see  [https://arxiv.org/abs/nucl-th/0006083 the study by H. Arenhövel] concluding that "''It is very doubtful, if not impossible, that one can extract in a simple manner the neutron spin asymmetry from the spin asymmetry of the deuteron.''" [https://arxiv.org/abs/nucl-th/0407058 A later paper] confirms this stating "''This means that a direct experimental access to the neutron spin asymme- try from a measurement of the spin asymmetry of the deuteron by subtracting the one of the free proton is not possible. On the other hand, polarization data of me- son production on the deuteron certainly will provide a more detailed test of meson production on the neutron and thus, in an indirect manner, on its spin asymmetry.''" This is a problem for the MAMI/ELSA data, but less for us because at large nu, the problematic contribution from the 2-body breakup is gone. Therefore, our extraction of the neutron information will be reliable and</div></td><td class='diff-marker'>+</td><td style="color:black; font-size: 88%; border-style: solid; border-width: 1px 1px 1px 4px; border-radius: 0.33em; border-color: #a3d3ff; vertical-align: top; white-space: pre-wrap;"><div>*Remembered why so far the GDH data on neutron have not been published in spite of the available deuteron data from MAMI/ELSA. This is because of the very large contribution from deuteron 2-body breakup at very low nu. With the 1/nu weighting, <ins class="diffchange diffchange-inline">the 2-body breakup </ins>cancels almost exactly the resonance+large nu part<ins class="diffchange diffchange-inline">. Accurately </ins>correcting for it to get the neutron information is very delicate without a very good model of the deuteron structure, see  [https://arxiv.org/abs/nucl-th/0006083 the study by H. Arenhövel] concluding that "''It is very doubtful, if not impossible, that one can extract in a simple manner the neutron spin asymmetry from the spin asymmetry of the deuteron.''" [https://arxiv.org/abs/nucl-th/0407058 A later paper] confirms this stating "''This means that a direct experimental access to the neutron spin asymme- try from a measurement of the spin asymmetry of the deuteron by subtracting the one of the free proton is not possible. On the other hand, polarization data of me- son production on the deuteron certainly will provide a more detailed test of meson production on the neutron and thus, in an indirect manner, on its spin asymmetry.''" This is a problem for the MAMI/ELSA data, but less for us because at large nu, the problematic contribution from the 2-body breakup is gone. Therefore, our extraction of the neutron information will be reliable<ins class="diffchange diffchange-inline">, </ins>and <ins class="diffchange diffchange-inline">consequently:</ins></div></td></tr>
<tr><td class='diff-marker'>−</td><td style="color:black; font-size: 88%; border-style: solid; border-width: 1px 1px 1px 4px; border-radius: 0.33em; border-color: #ffe49c; vertical-align: top; white-space: pre-wrap;"><div>** The short-term goal of the proposal (studying the convergence) is unaffected by the issue;   </div></td><td class='diff-marker'>+</td><td style="color:black; font-size: 88%; border-style: solid; border-width: 1px 1px 1px 4px; border-radius: 0.33em; border-color: #a3d3ff; vertical-align: top; white-space: pre-wrap;"><div>** The short-term goal of the proposal (studying the <ins class="diffchange diffchange-inline">sum </ins>convergence) is unaffected by the issue;   </div></td></tr>
<tr><td class='diff-marker'>−</td><td style="color:black; font-size: 88%; border-style: solid; border-width: 1px 1px 1px 4px; border-radius: 0.33em; border-color: #ffe49c; vertical-align: top; white-space: pre-wrap;"><div>** The longer term goal for the neutron (test of the GDH sum rule) is affected by the issue but there are solutions: instead of complementing the possibly problematic MAMI/ELSA data, we can complement the JLab electroproduction on neutron from 3He <del class="diffchange diffchange-inline">data </del>extrapolated to Q=0 (the 3He data does not suffer from this problem). Since the electroproduction data are also limited to <del class="diffchange diffchange-inline">below </del>1.7 GeV (photoproduction <del class="diffchange diffchange-inline">max </del>nu <del class="diffchange diffchange-inline">is </del>1.8 GeV) the point of the longer term goal remains. <del class="diffchange diffchange-inline">Furthermore, the </del>development of models and expected data on the deuteron 2-body breakup from HIγS may</div></td><td class='diff-marker'>+</td><td style="color:black; font-size: 88%; border-style: solid; border-width: 1px 1px 1px 4px; border-radius: 0.33em; border-color: #a3d3ff; vertical-align: top; white-space: pre-wrap;"><div>** The longer term goal for the neutron (test of the GDH sum rule) is <ins class="diffchange diffchange-inline">somewhat </ins>affected by the issue<ins class="diffchange diffchange-inline">, </ins>but there are solutions:  </div></td></tr>
<tr><td colspan="2"> </td><td class='diff-marker'>+</td><td style="color:black; font-size: 88%; border-style: solid; border-width: 1px 1px 1px 4px; border-radius: 0.33em; border-color: #a3d3ff; vertical-align: top; white-space: pre-wrap;"><div><ins class="diffchange diffchange-inline">***</ins>instead of complementing the possibly problematic MAMI/ELSA data, we can complement the JLab electroproduction <ins class="diffchange diffchange-inline">data </ins>on neutron from 3He<ins class="diffchange diffchange-inline">, </ins>extrapolated to Q=0 (the 3He data does not suffer from this problem). Since the electroproduction data are also limited to <ins class="diffchange diffchange-inline">nu < </ins>1.7 GeV (<ins class="diffchange diffchange-inline">to compare to </ins>photoproduction<ins class="diffchange diffchange-inline">: </ins>nu <ins class="diffchange diffchange-inline">< </ins>1.8 GeV) the point of the longer term goal remains.  </div></td></tr>
<tr><td colspan="2"> </td><td class='diff-marker'>+</td><td style="color:black; font-size: 88%; border-style: solid; border-width: 1px 1px 1px 4px; border-radius: 0.33em; border-color: #a3d3ff; vertical-align: top; white-space: pre-wrap;"><div><ins class="diffchange diffchange-inline">***The </ins>development of models and expected data on the deuteron 2-body breakup from HIγS may <ins class="diffchange diffchange-inline">solve the issue for the deuteron photoproduction data.</ins></div></td></tr>
<tr><td colspan="2"> </td><td class='diff-marker'>+</td><td style="color:black; font-size: 88%; border-style: solid; border-width: 1px 1px 1px 4px; border-radius: 0.33em; border-color: #a3d3ff; vertical-align: top; white-space: pre-wrap;"><div><ins class="diffchange diffchange-inline">*Got a message from Eugene regarding target polarization with spins anti-parallel to the solenoid B-field. Answered that it was possible to do, but with 1/2 the relation time of the parallel configuration. This is still 1400h so it is no issue for the short GDH run time.</ins></div></td></tr>
</table>Deurpamhttps://halldweb.jlab.org/wiki/index.php?title=07/07/2020&diff=100117&oldid=prevDeurpam at 13:56, 8 July 20202020-07-08T13:56:34Z<p></p>
<table class='diff diff-contentalign-left'>
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<tr><td class='diff-marker'> </td><td style="background-color: #f9f9f9; color: #333333; font-size: 88%; border-style: solid; border-width: 1px 1px 1px 4px; border-radius: 0.33em; border-color: #e6e6e6; vertical-align: top; white-space: pre-wrap;"></td><td class='diff-marker'> </td><td style="background-color: #f9f9f9; color: #333333; font-size: 88%; border-style: solid; border-width: 1px 1px 1px 4px; border-radius: 0.33em; border-color: #e6e6e6; vertical-align: top; white-space: pre-wrap;"></td></tr>
<tr><td class='diff-marker'> </td><td style="background-color: #f9f9f9; color: #333333; font-size: 88%; border-style: solid; border-width: 1px 1px 1px 4px; border-radius: 0.33em; border-color: #e6e6e6; vertical-align: top; white-space: pre-wrap;"><div>A. D.:  </div></td><td class='diff-marker'> </td><td style="background-color: #f9f9f9; color: #333333; font-size: 88%; border-style: solid; border-width: 1px 1px 1px 4px; border-radius: 0.33em; border-color: #e6e6e6; vertical-align: top; white-space: pre-wrap;"><div>A. D.:  </div></td></tr>
<tr><td class='diff-marker'>−</td><td style="color:black; font-size: 88%; border-style: solid; border-width: 1px 1px 1px 4px; border-radius: 0.33em; border-color: #ffe49c; vertical-align: top; white-space: pre-wrap;"><div>*Remembered why so far the GDH data on neutron have not been published in spite of the available deuteron data from MAMI/ELSA. This is because of the very large contribution from the deuteron 2-body breakup at very low nu. With the 1/nu weighting, it cancels almost exactly the resonance+large nu part and accurately correcting for it to get the neutron information is very delicate without a very good model of the deuteron structure, see  [https://arxiv.org/abs/nucl-th/0006083 the study by H. Arenhövel] concluding that ''It is very doubtful, if not impossible, that one can extract in a simple manner the neutron spin asymmetry from the spin asymmetry of the deuteron.''  </div></td><td class='diff-marker'>+</td><td style="color:black; font-size: 88%; border-style: solid; border-width: 1px 1px 1px 4px; border-radius: 0.33em; border-color: #a3d3ff; vertical-align: top; white-space: pre-wrap;"><div>*Remembered why so far the GDH data on neutron have not been published in spite of the available deuteron data from MAMI/ELSA. This is because of the very large contribution from the deuteron 2-body breakup at very low nu. With the 1/nu weighting, it cancels almost exactly the resonance+large nu part and accurately correcting for it to get the neutron information is very delicate without a very good model of the deuteron structure, see  [https://arxiv.org/abs/nucl-th/0006083 the study by H. Arenhövel] concluding that <ins class="diffchange diffchange-inline">"</ins>''It is very doubtful, if not impossible, that one can extract in a simple manner the neutron spin asymmetry from the spin asymmetry of the deuteron.''<ins class="diffchange diffchange-inline">" [https://arxiv.org/abs/nucl-th/0407058 A later paper] confirms this stating "''This means that a direct experimental access to the neutron spin asymme- try from a measurement of the spin asymmetry of the deuteron by subtracting the one of the free proton is not possible. On the other hand, polarization data of me- son production on the deuteron certainly will provide a more detailed test of meson production on the neutron and thus, in an indirect manner, on its spin asymmetry.''" </ins>This is a problem for the MAMI/ELSA data, but less for us <ins class="diffchange diffchange-inline">because at large nu, </ins>the <ins class="diffchange diffchange-inline">problematic contribution from the 2-body breakup is gone. Therefore, our extraction of the neutron information will be reliable and</ins></div></td></tr>
<tr><td class='diff-marker'>−</td><td style="color:black; font-size: 88%; border-style: solid; border-width: 1px 1px 1px 4px; border-radius: 0.33em; border-color: #ffe49c; vertical-align: top; white-space: pre-wrap;"><div>This is a problem for the MAMI/ELSA data, but less for us <del class="diffchange diffchange-inline">for </del>the <del class="diffchange diffchange-inline">following reason:</del></div></td><td class='diff-marker'>+</td><td style="color:black; font-size: 88%; border-style: solid; border-width: 1px 1px 1px 4px; border-radius: 0.33em; border-color: #a3d3ff; vertical-align: top; white-space: pre-wrap;"><div>** The <ins class="diffchange diffchange-inline">short-term goal of the proposal (studying the convergence) is unaffected by the issue;  </ins></div></td></tr>
<tr><td class='diff-marker'>−</td><td style="color:black; font-size: 88%; border-style: solid; border-width: 1px 1px 1px 4px; border-radius: 0.33em; border-color: #ffe49c; vertical-align: top; white-space: pre-wrap;"><div>**The problematic <del class="diffchange diffchange-inline">contribution </del>from the 2-body breakup</div></td><td class='diff-marker'>+</td><td style="color:black; font-size: 88%; border-style: solid; border-width: 1px 1px 1px 4px; border-radius: 0.33em; border-color: #a3d3ff; vertical-align: top; white-space: pre-wrap;"><div><ins class="diffchange diffchange-inline">** The longer term goal for the neutron (test of the GDH sum rule) is affected by the issue but there are solutions: instead of complementing the possibly </ins>problematic <ins class="diffchange diffchange-inline">MAMI/ELSA data, we can complement the JLab electroproduction on neutron </ins>from <ins class="diffchange diffchange-inline">3He data extrapolated to Q=0 (</ins>the <ins class="diffchange diffchange-inline">3He data does not suffer from this problem). Since the electroproduction data are also limited to below 1.7 GeV (photoproduction max nu is 1.8 GeV) the point of the longer term goal remains. Furthermore, the development of models and expected data on the deuteron </ins>2-body breakup <ins class="diffchange diffchange-inline">from HIγS may</ins></div></td></tr>
</table>Deurpamhttps://halldweb.jlab.org/wiki/index.php?title=07/07/2020&diff=100116&oldid=prevDeurpam at 13:22, 8 July 20202020-07-08T13:22:15Z<p></p>
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<tr><td class='diff-marker'> </td><td style="background-color: #f9f9f9; color: #333333; font-size: 88%; border-style: solid; border-width: 1px 1px 1px 4px; border-radius: 0.33em; border-color: #e6e6e6; vertical-align: top; white-space: pre-wrap;"><div>J. S.:</div></td><td class='diff-marker'> </td><td style="background-color: #f9f9f9; color: #333333; font-size: 88%; border-style: solid; border-width: 1px 1px 1px 4px; border-radius: 0.33em; border-color: #e6e6e6; vertical-align: top; white-space: pre-wrap;"><div>J. S.:</div></td></tr>
<tr><td class='diff-marker'> </td><td style="background-color: #f9f9f9; color: #333333; font-size: 88%; border-style: solid; border-width: 1px 1px 1px 4px; border-radius: 0.33em; border-color: #e6e6e6; vertical-align: top; white-space: pre-wrap;"></td><td class='diff-marker'> </td><td style="background-color: #f9f9f9; color: #333333; font-size: 88%; border-style: solid; border-width: 1px 1px 1px 4px; border-radius: 0.33em; border-color: #e6e6e6; vertical-align: top; white-space: pre-wrap;"></td></tr>
<tr><td class='diff-marker'>−</td><td style="color:black; font-size: 88%; border-style: solid; border-width: 1px 1px 1px 4px; border-radius: 0.33em; border-color: #ffe49c; vertical-align: top; white-space: pre-wrap;"><div>A. D.:</div></td><td class='diff-marker'>+</td><td style="color:black; font-size: 88%; border-style: solid; border-width: 1px 1px 1px 4px; border-radius: 0.33em; border-color: #a3d3ff; vertical-align: top; white-space: pre-wrap;"><div>A. D.:  </div></td></tr>
<tr><td colspan="2"> </td><td class='diff-marker'>+</td><td style="color:black; font-size: 88%; border-style: solid; border-width: 1px 1px 1px 4px; border-radius: 0.33em; border-color: #a3d3ff; vertical-align: top; white-space: pre-wrap;"><div><ins class="diffchange diffchange-inline">*Remembered why so far the GDH data on neutron have not been published in spite of the available deuteron data from MAMI/ELSA. This is because of the very large contribution from the deuteron 2-body breakup at very low nu. With the 1/nu weighting, it cancels almost exactly the resonance+large nu part and accurately correcting for it to get the neutron information is very delicate without a very good model of the deuteron structure, see  [https://arxiv.org/abs/nucl-th/0006083 the study by H. Arenhövel] concluding that ''It is very doubtful, if not impossible, that one can extract in a simple manner the neutron spin asymmetry from the spin asymmetry of the deuteron.'' </ins></div></td></tr>
<tr><td colspan="2"> </td><td class='diff-marker'>+</td><td style="color:black; font-size: 88%; border-style: solid; border-width: 1px 1px 1px 4px; border-radius: 0.33em; border-color: #a3d3ff; vertical-align: top; white-space: pre-wrap;"><div><ins class="diffchange diffchange-inline">This is a problem for the MAMI/ELSA data, but less for us for the following reason:</ins></div></td></tr>
<tr><td colspan="2"> </td><td class='diff-marker'>+</td><td style="color:black; font-size: 88%; border-style: solid; border-width: 1px 1px 1px 4px; border-radius: 0.33em; border-color: #a3d3ff; vertical-align: top; white-space: pre-wrap;"><div><ins class="diffchange diffchange-inline">**The problematic contribution from the 2-body breakup</ins></div></td></tr>
</table>Deurpamhttps://halldweb.jlab.org/wiki/index.php?title=07/07/2020&diff=100061&oldid=prevDeurpam at 17:27, 7 July 20202020-07-07T17:27:03Z<p></p>
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<td colspan='2' style="background-color: white; color:black; text-align: center;">Revision as of 17:27, 7 July 2020</td>
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<tr><td class='diff-marker'> </td><td style="background-color: #f9f9f9; color: #333333; font-size: 88%; border-style: solid; border-width: 1px 1px 1px 4px; border-radius: 0.33em; border-color: #e6e6e6; vertical-align: top; white-space: pre-wrap;"><div>M.D:</div></td><td class='diff-marker'> </td><td style="background-color: #f9f9f9; color: #333333; font-size: 88%; border-style: solid; border-width: 1px 1px 1px 4px; border-radius: 0.33em; border-color: #e6e6e6; vertical-align: top; white-space: pre-wrap;"><div>M.D:</div></td></tr>
<tr><td class='diff-marker'> </td><td style="background-color: #f9f9f9; color: #333333; font-size: 88%; border-style: solid; border-width: 1px 1px 1px 4px; border-radius: 0.33em; border-color: #e6e6e6; vertical-align: top; white-space: pre-wrap;"></td><td class='diff-marker'> </td><td style="background-color: #f9f9f9; color: #333333; font-size: 88%; border-style: solid; border-width: 1px 1px 1px 4px; border-radius: 0.33em; border-color: #e6e6e6; vertical-align: top; white-space: pre-wrap;"></td></tr>
<tr><td class='diff-marker'>−</td><td style="color:black; font-size: 88%; border-style: solid; border-width: 1px 1px 1px 4px; border-radius: 0.33em; border-color: #ffe49c; vertical-align: top; white-space: pre-wrap;"><div>S.Š: (By email): I have coded the unpolarized Bethe-Heitler cross-section for a nuclear (carbon) target, and the result is shown in [https://halldweb.jlab.org/wiki/images/9/97/Cp_07_07_2020.pdf the attached figure] in orange: the elastic part (dotted), the elastic+quasielastic  (dashed) and the elastic+quasielastic+inelastic = total (full curve).  I used the parameterizations (B49), (B52,53) and (B56,57) from Tsai (1974).</div></td><td class='diff-marker'>+</td><td style="color:black; font-size: 88%; border-style: solid; border-width: 1px 1px 1px 4px; border-radius: 0.33em; border-color: #a3d3ff; vertical-align: top; white-space: pre-wrap;"><div>S.Š: (By email):  </div></td></tr>
<tr><td colspan="2"> </td><td class='diff-marker'>+</td><td style="color:black; font-size: 88%; border-style: solid; border-width: 1px 1px 1px 4px; border-radius: 0.33em; border-color: #a3d3ff; vertical-align: top; white-space: pre-wrap;"><div> </div></td></tr>
<tr><td colspan="2"> </td><td class='diff-marker'>+</td><td style="color:black; font-size: 88%; border-style: solid; border-width: 1px 1px 1px 4px; border-radius: 0.33em; border-color: #a3d3ff; vertical-align: top; white-space: pre-wrap;"><div>I have coded the unpolarized Bethe-Heitler cross-section for a nuclear (carbon) target, and the result is shown in [https://halldweb.jlab.org/wiki/images/9/97/Cp_07_07_2020.pdf the attached figure] in orange: the elastic part (dotted), the elastic+quasielastic  (dashed) and the elastic+quasielastic+inelastic = total (full curve).  I used the parameterizations (B49), (B52,53) and (B56,57) from Tsai (1974).</div></td></tr>
<tr><td colspan="2"> </td><td class='diff-marker'>+</td><td style="color:black; font-size: 88%; border-style: solid; border-width: 1px 1px 1px 4px; border-radius: 0.33em; border-color: #a3d3ff; vertical-align: top; white-space: pre-wrap;"><div> </div></td></tr>
<tr><td class='diff-marker'> </td><td style="background-color: #f9f9f9; color: #333333; font-size: 88%; border-style: solid; border-width: 1px 1px 1px 4px; border-radius: 0.33em; border-color: #e6e6e6; vertical-align: top; white-space: pre-wrap;"><div>Now how does that compare to the free proton case?  For now the only meaningful comparison I was able to make was in the elastic part.  Assuming (B49) for the nuclear elastic form-factor I learn that this scales as mass*Z^2 (!!!).  So I have multiplied the elastic part of free-proton Bethe-Heitler by 12*36 (!!!) and got</div></td><td class='diff-marker'> </td><td style="background-color: #f9f9f9; color: #333333; font-size: 88%; border-style: solid; border-width: 1px 1px 1px 4px; border-radius: 0.33em; border-color: #e6e6e6; vertical-align: top; white-space: pre-wrap;"><div>Now how does that compare to the free proton case?  For now the only meaningful comparison I was able to make was in the elastic part.  Assuming (B49) for the nuclear elastic form-factor I learn that this scales as mass*Z^2 (!!!).  So I have multiplied the elastic part of free-proton Bethe-Heitler by 12*36 (!!!) and got</div></td></tr>
<tr><td class='diff-marker'> </td><td style="background-color: #f9f9f9; color: #333333; font-size: 88%; border-style: solid; border-width: 1px 1px 1px 4px; border-radius: 0.33em; border-color: #e6e6e6; vertical-align: top; white-space: pre-wrap;"><div>the green dotted line.</div></td><td class='diff-marker'> </td><td style="background-color: #f9f9f9; color: #333333; font-size: 88%; border-style: solid; border-width: 1px 1px 1px 4px; border-radius: 0.33em; border-color: #e6e6e6; vertical-align: top; white-space: pre-wrap;"><div>the green dotted line.</div></td></tr>
<tr><td colspan="2"> </td><td class='diff-marker'>+</td><td style="color:black; font-size: 88%; border-style: solid; border-width: 1px 1px 1px 4px; border-radius: 0.33em; border-color: #a3d3ff; vertical-align: top; white-space: pre-wrap;"><div><ins style="font-weight: bold; text-decoration: none;"></ins></div></td></tr>
<tr><td class='diff-marker'> </td><td style="background-color: #f9f9f9; color: #333333; font-size: 88%; border-style: solid; border-width: 1px 1px 1px 4px; border-radius: 0.33em; border-color: #e6e6e6; vertical-align: top; white-space: pre-wrap;"><div>Am I telling you that we should have multiplied the proton BH cross-sections by 12*36 = 432 instead of 6 or 12 ??</div></td><td class='diff-marker'> </td><td style="background-color: #f9f9f9; color: #333333; font-size: 88%; border-style: solid; border-width: 1px 1px 1px 4px; border-radius: 0.33em; border-color: #e6e6e6; vertical-align: top; white-space: pre-wrap;"><div>Am I telling you that we should have multiplied the proton BH cross-sections by 12*36 = 432 instead of 6 or 12 ??</div></td></tr>
<tr><td class='diff-marker'> </td><td style="background-color: #f9f9f9; color: #333333; font-size: 88%; border-style: solid; border-width: 1px 1px 1px 4px; border-radius: 0.33em; border-color: #e6e6e6; vertical-align: top; white-space: pre-wrap;"><div>I was hoping that the target mass ("mi" in the paper) cancels somewhere, but it does not seem so.  In Eq. (2.1), for instance, there is a mi in the numerator, but (k*pi) in the denominator is just Egamma*mi, so both mi cancel.  So there is this unfortunate 12 in the form-factor and there is a 36 factor due to the charge in (B49), I am afraid, unless I am missing something.</div></td><td class='diff-marker'> </td><td style="background-color: #f9f9f9; color: #333333; font-size: 88%; border-style: solid; border-width: 1px 1px 1px 4px; border-radius: 0.33em; border-color: #e6e6e6; vertical-align: top; white-space: pre-wrap;"><div>I was hoping that the target mass ("mi" in the paper) cancels somewhere, but it does not seem so.  In Eq. (2.1), for instance, there is a mi in the numerator, but (k*pi) in the denominator is just Egamma*mi, so both mi cancel.  So there is this unfortunate 12 in the form-factor and there is a 36 factor due to the charge in (B49), I am afraid, unless I am missing something.</div></td></tr>
<tr><td colspan="2"> </td><td class='diff-marker'>+</td><td style="color:black; font-size: 88%; border-style: solid; border-width: 1px 1px 1px 4px; border-radius: 0.33em; border-color: #a3d3ff; vertical-align: top; white-space: pre-wrap;"><div><ins style="font-weight: bold; text-decoration: none;"></ins></div></td></tr>
<tr><td class='diff-marker'> </td><td style="background-color: #f9f9f9; color: #333333; font-size: 88%; border-style: solid; border-width: 1px 1px 1px 4px; border-radius: 0.33em; border-color: #e6e6e6; vertical-align: top; white-space: pre-wrap;"><div>It is harder to compare the inelastic parts on the same plot, as these scale linearly with Z, as in (B52,53) and (B56,57).</div></td><td class='diff-marker'> </td><td style="background-color: #f9f9f9; color: #333333; font-size: 88%; border-style: solid; border-width: 1px 1px 1px 4px; border-radius: 0.33em; border-color: #e6e6e6; vertical-align: top; white-space: pre-wrap;"><div>It is harder to compare the inelastic parts on the same plot, as these scale linearly with Z, as in (B52,53) and (B56,57).</div></td></tr>
<tr><td class='diff-marker'> </td><td style="background-color: #f9f9f9; color: #333333; font-size: 88%; border-style: solid; border-width: 1px 1px 1px 4px; border-radius: 0.33em; border-color: #e6e6e6; vertical-align: top; white-space: pre-wrap;"></td><td class='diff-marker'> </td><td style="background-color: #f9f9f9; color: #333333; font-size: 88%; border-style: solid; border-width: 1px 1px 1px 4px; border-radius: 0.33em; border-color: #e6e6e6; vertical-align: top; white-space: pre-wrap;"></td></tr>
</table>Deurpamhttps://halldweb.jlab.org/wiki/index.php?title=07/07/2020&diff=100060&oldid=prevDeurpam: Created page with "Present: M.D., A.D., J.S., S.Š General: M.D: S.Š: (By email): I have coded the unpolarized Bethe-Heitler cross-section for a nuclear (carbon) target, and the result is sh..."2020-07-07T17:26:38Z<p>Created page with "Present: M.D., A.D., J.S., S.Š General: M.D: S.Š: (By email): I have coded the unpolarized Bethe-Heitler cross-section for a nuclear (carbon) target, and the result is sh..."</p>
<p><b>New page</b></p><div>Present: M.D., A.D., J.S., S.Š<br />
<br />
General:<br />
<br />
M.D:<br />
<br />
S.Š: (By email): I have coded the unpolarized Bethe-Heitler cross-section for a nuclear (carbon) target, and the result is shown in [https://halldweb.jlab.org/wiki/images/9/97/Cp_07_07_2020.pdf the attached figure] in orange: the elastic part (dotted), the elastic+quasielastic (dashed) and the elastic+quasielastic+inelastic = total (full curve). I used the parameterizations (B49), (B52,53) and (B56,57) from Tsai (1974).<br />
Now how does that compare to the free proton case? For now the only meaningful comparison I was able to make was in the elastic part. Assuming (B49) for the nuclear elastic form-factor I learn that this scales as mass*Z^2 (!!!). So I have multiplied the elastic part of free-proton Bethe-Heitler by 12*36 (!!!) and got<br />
the green dotted line.<br />
Am I telling you that we should have multiplied the proton BH cross-sections by 12*36 = 432 instead of 6 or 12 ??<br />
I was hoping that the target mass ("mi" in the paper) cancels somewhere, but it does not seem so. In Eq. (2.1), for instance, there is a mi in the numerator, but (k*pi) in the denominator is just Egamma*mi, so both mi cancel. So there is this unfortunate 12 in the form-factor and there is a 36 factor due to the charge in (B49), I am afraid, unless I am missing something.<br />
It is harder to compare the inelastic parts on the same plot, as these scale linearly with Z, as in (B52,53) and (B56,57).<br />
<br />
<br />
J. S.:<br />
<br />
A. D.:</div>Deurpam