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<p>Hi Sebastian,</p>
<p>For figure 5, the limit on the reduced chi2 that I put affects
the set of accepted sets of Ju and Jd. The Limit is now 3.5, if I
move it ot 5 I have a set of accepted sets of Ju and Jd that
contains positive values of Ju (50% of selected fits). So maybe it
is our choice that gave the impression that only negative Ju
values are reasonable!<br>
</p>
<p>My reasoning is that there are preferred values for Jd (positive
around 0.15) but no preferred values for Ju, I attach here again
the same plot showing Ju vs Jd versus chi2 from a different angle.
It shows that on the Ju axes, the distribution for chi2 is almost
Flat.<img src="cid:part1.VRBGEUqY.X5FX6T4d@jlab.org" alt=""></p>
<p>However, my take on this is that rather none of the combinations
of Ju and Jd reproduces the data correctly. Even for the ones we
chose to put in the figure 5, it is quite clear that the trend
seen in the data is not consistant with the curves. Moreover, VGG
predictions remain model dependant predictions and we do not
intend to consider them as a strong physics conclusions on the
values of Ju and Jd.</p>
<p>thanks</p>
<p>Best regards</p>
<p>Adam<br>
</p>
<div class="moz-cite-prefix">Le 05/06/2024 à 14:38, Sebastian Kuhn a
écrit :<br>
</div>
<blockquote type="cite"
cite="mid:095C1E05-E642-473F-AB4B-D1F0873ACEF2@jlab.org">
<pre class="moz-quote-pre" wrap="">Just a quick question: Why are all the preferred values for J_u negative and for J_d positive? This seems very counter-intuitive, given that the quark helicity contributions to J have the exact opposite sign. This would require enormous (overcompensating) orbital angular momenta to explain.
- Sebastian
</pre>
<blockquote type="cite">
<pre class="moz-quote-pre" wrap="">On Jun 5, 2024, at 4:07 AM, ajhobart via Clas12_rgb <a class="moz-txt-link-rfc2396E" href="mailto:clas12_rgb@jlab.org"><clas12_rgb@jlab.org></a> wrote:
Dear Valery, RGB,
following our discussion during the last RGB meeting concerning figure 5 of the nDVCS paper draft, we have performed a scan using VGG of different values of Ju and Jd and evaluating for each set a chi2 with the 9 data points that we extract with our analysis. Indeed, this scan has shown that there are other values of Ju and Jd that are more "preferred" by our extracted harmonics than the ones we had initially put in the paper. We have updated figure 5 accordingly (I attach it here also).
color code for figure 5
// ju jd reduced chi2
//-0.45 0.2 3.03423 blue
//-0.25 0.15 3.19268 black
//-0.2 0.15 3.1004 Red
Attached also you will find the plot with Ju, Jd and chi2 value for each set as you requested. It seems that there is a particular preferred range for Jd (around 0.15) but none for Ju.
thanks
Best regards
Adam
<bsa_q2xbjt_coloronline_newVGG.pdf><jujdchi2.png>_______________________________________________
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</pre>
</blockquote>
<pre class="moz-quote-pre" wrap="">
</pre>
</blockquote>
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