<div dir="ltr"><div class="gmail_default" style="font-family:verdana,sans-serif">Dear everyone,<br></div><div class="gmail_quote"><div dir="ltr"><div><font face="verdana, sans-serif"><br></font></div><div><font face="verdana, sans-serif">Thank you very much for the comments!</font></div><div><font face="verdana, sans-serif"><br></font></div><div><font face="verdana, sans-serif">First of all apologies for not spell-checking before sending it round, I finished very late and forgot to do that, thanks for picking up all my typos (slightly horrified by how many there were...)! To avoid spamming you with ten emails I'll answer all of the comments here, roughly grouped (some of them overlap):</font></div><div><font face="verdana, sans-serif"><br></font></div><div><font face="verdana, sans-serif"><span style="font-size:13px">Hervé</span>, many thanks for the fixes on the theory parts, I'll put them in! <br></font></div><div><font face="verdana, sans-serif"><br></font></div><div><font face="verdana, sans-serif">Volker, Michel, Silvia -- on the matter on the two asymmetries: I agree that TSA doesn't look as good and given all the conflicting opinions, the uncertainty on whether I can even release this from CLAS and the fact that I somehow need to squeeze it all into four pages (with the extra bits of clarification and references), I think it may just be simpler to remove it. It's really very preliminary and indeed a "raw asymmetry" -- I'll just refer to the analysis in the text instead. </font></div><div><font face="verdana, sans-serif"><br></font></div><div><font face="verdana, sans-serif">Silvia, thanks for the comments, the asymmetries are defined in the standard way (difference of numbers of events over sum), I omitted the formulae for space reasons but I can add them. Not all the correction factors are included: no pi0 or any other background subtraction except what is reduced via exclusivity cuts; the dilution factor is also not included in the displayed fit parameter on the TSA (I get about 0.5 for it); I'm not sure what you mean by polarisations, though -- these are assigned on an event-by-event basis so should be correct. However, I don't think these features are necessarily an issue, the magnitude of the real asymmetries is quite likely different from what is seen in the fit, but that is what can be expected from the "preliminary" label -- these are just proceedings, so a write-up of my talk which presented an analysis in progress. I will add a sentence to make it more explicit that not all corrections are applied. </font><span style="font-family:verdana,sans-serif">I use the two fitting functions which are suggested by the literature in the respective cases -- I agree that there should be a reference, I'll add it! But if anyone is misled by comparing parameters from two different functions applied to distributions from two different variables, well, I think they should read the paper more carefully -- p0, after all, is a fairly standard way of designating the first parameter of a fit and I think it's implicit that this is not the proper symbol for a particular variable. In any case, the TSA will be removed. </span><font face="verdana, sans-serif">I'll </font><span style="font-family:verdana,sans-serif">add a reference and a brief comment for the VGG (space was too limited to go into details!).</span></div><div><font face="verdana, sans-serif"><br></font></div><div><font face="verdana, sans-serif">Michel, thanks for the corrections -- please see answers for the non-typo points below:</font></div><span class=""><div><font face="verdana, sans-serif"><br></font></div><div><font face="verdana, sans-serif"><span style="font-size:13px">*abstract, l.3:</span><br style="font-size:13px"><span style="font-size:13px">"Data from both proton and neutron targets is required for an extraction of all accesible GPDs...". It is not clear to me what are the "accessible GPDs" ? What are the "non-accessible GPDs" ?</span><br></font></div></span><div><font face="verdana, sans-serif">-- valid point! </font></div><span class=""><div><font face="verdana, sans-serif"><br></font></div><div><font face="verdana, sans-serif"><span style="font-size:13px">*l.8: "scintillator wall". It might be strange to call our IC made of</span><br style="font-size:13px"><span style="font-size:13px">PbWO4 crystals "scintillator wall". "Scintillators" refer to something</span><br style="font-size:13px"><span style="font-size:13px">else in general.</span><br></font></div></span><div><span style="font-size:13px"><font face="verdana, sans-serif">-- Lead tungstanate is a scintillator, surely? Isn't scintillation light in it how we detect the photons? I can say "wall of scintillator crystals" to make its segmented nature more evident...</font></span></div><span class=""><div><span style="font-size:13px"><font face="verdana, sans-serif"><br></font></span></div><div><font face="verdana, sans-serif"><span style="font-size:13px">*par.2, l.7: "the recoil electron". A bit strange. "scattered electron" rather ?</span><span style="font-size:13px"><br></span></font></div></span><div><font face="verdana, sans-serif">-- Agreed!</font></div><span class=""><div><font face="verdana, sans-serif"><br></font></div><div><font face="verdana, sans-serif"><span style="font-size:13px">*l.14: "W>2 GeV/c2" Sometimes you use the "c" and sometimes not</span><br style="font-size:13px"><span style="font-size:13px">(line below: "Q2>1 GeV2"); you probably have to choose and stick to one notation.</span><br></font></div></span><div><span style="font-size:13px"><font face="verdana, sans-serif">-- Absolutely, I lost the c^4 on Q^2. </font></span></div><span class=""><div><span style="font-size:13px"><font face="verdana, sans-serif"><br></font></span></div><div><font face="verdana, sans-serif"><span style="font-size:13px">*l.16: "factorisation...into a hard-scattering and a soft-scattering part applies". You never introduced those "hard" and "soft parts". It seems</span><br style="font-size:13px"><span style="font-size:13px">to come out of the blue...</span><span style="font-size:13px"><br></span></font></div></span><div><span style="font-size:13px"><font face="verdana, sans-serif">-- I wanted to motivate those cuts in brief, but I agree this is a little oblique. I will see how much space I will have and will either take it out completely or explain in brief.</font></span></div><span class=""><div><span style="font-size:13px"><font face="verdana, sans-serif"><br></font></span></div><div><font face="verdana, sans-serif"><span style="font-size:13px">*last sentence of par.2: "(to estimate which the same particle identification and distribution cuts were applied to 14ND3 data)"</span><br style="font-size:13px"><span style="font-size:13px">sounds bizarre.</span><span style="font-size:13px"><br></span></font></div></span><div><span style="font-size:13px"><font face="verdana, sans-serif">-- I agree that was a bit condensed. Volker, to also answer your question on this: I mean I subtracted the distribution obtained after applying exactly the same cuts on NH3 data, from what I had on ND3 (normalised). This enhanced the features which are due to the neutron in the deuteron, so the effect of the exclusivity cuts could be checked. Some neutron-in-nitrogen background is, however, still present in the data used to make the asymmetries (analysis-wise this is to be addressed when my teaching stops for the year!).</font></span></div><span class=""><div><font face="verdana, sans-serif"><br></font></div><div><font face="verdana, sans-serif"><span style="font-size:13px">*p.5, bibliography: "[5]:... PRL 99". ->"Phys.Rv.Lett."</span><br style="font-size:13px"><span style="font-size:13px">[6]: instead of "private communication", you can probably refer</span><br style="font-size:13px"><span style="font-size:13px">to the original CLAS proposal. This is true that I/we should publish on n-DVCS some day.</span><br></font></div></span><div><span style="font-size:13px"><font face="verdana, sans-serif">-- I was going to ask you about that! I'll reference the proposal, had left it as a place-holder in case there was another publication. </font></span></div><div><font face="verdana, sans-serif"><br></font></div><div><font face="verdana, sans-serif">And sorry for making GPDs complex, that was a late-night glitch, thanks everyone for spotting that!</font></div><div><br></div><div><font face="verdana, sans-serif">I'll circulate an updated version,</font></div><div><font face="verdana, sans-serif"><br></font></div><div><font face="verdana, sans-serif">Many thanks again,</font></div><div><font face="verdana, sans-serif">Daria</font></div><div style="font-family:verdana,sans-serif"><br></div><div class="gmail_extra"><span class=""><br clear="all"><div><div><div dir="ltr"><div><div dir="ltr"><span><div><div><div><div><div><div><font face="arial,helvetica,sans-serif">~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~<br></font></div><font face="arial,helvetica,sans-serif">Dr Daria Sokhan<br></font></div><div><font face="arial,helvetica,sans-serif">Kelvin Building - Room 505<br></font></div><font face="arial,helvetica,sans-serif">School of Physics & Astronomy<br></font></div></div><font face="arial,helvetica,sans-serif">University of Glasgow <br></font></div><font face="arial,helvetica,sans-serif">Glasgow G12 8QQ </font><font face="arial,helvetica,sans-serif"> </font></div><font face="arial,helvetica,sans-serif">UK </font></span><span><font face="arial,helvetica,sans-serif"><span><span><font face="arial,helvetica,sans-serif"><font face="arial,helvetica,sans-serif">tel: <a href="tel:%2B%2044%20141%20330%202774" value="+441413302774" target="_blank">+ 44 141 330 2774</a><br></font></font></span></span>~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~</font></span></div></div></div></div></div>
<br></span><div><div class="h5"><div class="gmail_quote">On 1 December 2015 at 12:40, Silvia Niccolai <span dir="ltr"><<a href="mailto:silvia@jlab.org" target="_blank">silvia@jlab.org</a>></span> wrote:<br><blockquote class="gmail_quote" style="margin:0px 0px 0px 0.8ex;border-left-width:1px;border-left-color:rgb(204,204,204);border-left-style:solid;padding-left:1ex">Hello Michel/Daria,<br>
the main problem I see in showing those two asymmetries side by side is that it is not clear to me, and it is not explained in the text, how they are defined. Both asymmetries needs various correcting factors (polarizations, backgrounds, and for the TSA there is the dilution factor) that I am not sure are at this stage included in Daria's plots. So, the magnitude of the real asymmetries could be different from what is shown. besides, as you pointed out, the different choice of fitting function for the two observables can be misleading for whoever may end up just looking at the value of the p0 parameter in the fit window...<br>
If we want to keep the two observables, they were they are defined should be clearly stated, and the choice of fitting function should also be motivated.<br>
Best regards,<br>
Silvia<div><div><br>
<br>
<br>
On Tue, 1 Dec 2015, GUIDAL Michel (57321) wrote:<br>
<br>
</div></div><blockquote class="gmail_quote" style="margin:0px 0px 0px 0.8ex;border-left-width:1px;border-left-color:rgb(204,204,204);border-left-style:solid;padding-left:1ex"><div><div>
Hi Daria,<br>
<br>
Some more comments in addition to Volker's and Silvia's:<br>
<br>
*abstract, l.3:<br>
"Data from both proton and neutron targets is required for an extraction of all accesible GPDs...". It is not clear to me what are the "accessible GPDs" ? What are the "non-accessible GPDs" ?<br>
<br>
*introduction, par.1, l.1: "The most complete information..." might be too strong, there are probably things on nucleon structure which cannot<br>
be accessed through GTMDs. "A wealth of information..." or something like that to be cautious.<br>
<br>
*l-7/8: two times "the".<br>
<br>
*par.2, l.11: "extraction of the real parts of GPDs...". Silvia pointed it at some other place above, here it comes again: GPDs are real.<br>
Also, I wouldn't say that "cross-sections and double-spin asymmetries allow the extraction of the real part...", they are "sensitive to".<br>
For the true "extraction", one needs more than these 2 observables.<br>
<br>
*par.3, l.4: "the imaginary part of the GPD E". Again, GPDs are real.<br>
<br>
*l.5: "acesSible". Also, I would remove the "however", I don't see any<br>
contradiction with the fact that E is the least known.<br>
<br>
*p.2, 3 lines below eq.1. "This paper..." is not very nice. "These<br>
proceedings", "This article",...<br>
<br>
*section 2, par.1, l.6: "electRon".<br>
<br>
*l.8: "scintillator wall". It might be strange to call our IC made of<br>
PbWO4 crystals "scintillator wall". "Scintillators" refer to something<br>
else in general.<br>
<br>
*par.2, l.7: "the recoil electron". A bit strange. "scattered electron" rather ?<br>
<br>
*l.13: "stacettering" !!!<br>
<br>
*l.14: "W>2 GeV/c2" Sometimes you use the "c" and sometimes not<br>
(line below: "Q2>1 GeV2"); you probably have to choose and stick to one notation.<br>
<br>
*l.16: "factorisation...into a hard-scattering and a soft-scattering part applies". You never introduced those "hard" and "soft parts". It seems<br>
to come out of the blue...<br>
<br>
*last sentence of par.2: "(to estimate which the same particle identification and distribution cuts were applied to 14ND3 data)"<br>
sounds bizarre.<br>
<br>
*par.3, l.1: "traget".<br>
<br>
*Fig.2: I am not shocked by the target asymmetry. Maybe, there is<br>
no signal indeed but still this is information. I have no<br>
problem to leave it but no problem as well to remove it. Actually,<br>
the overall question is what is allowed to be released according to the CLAS rules ?<br>
By the way, in the caption, why do you fit the BSA and the TSA by 2 different functions ?<br>
<br>
*p.5, bibliography: "[5]:... PRL 99". ->"Phys.Rv.Lett."<br>
[6]: instead of "private communication", you can probably refer<br>
to the original CLAS proposal. This is true that I/we should publish on n-DVCS some day.<br>
<br>
Amities,<br>
<br>
Michel<br>
<br>
***<br>
Michel GUIDAL<br>
Institut de Physique Nucleaire<br>
Bat 100 - M130<br>
91406 ORSAY Cedex<br>
Tel: (33) 01 69 15 73 21<br>
Fax: (33) 01 69 15 64 70<br>
E-mail: <a href="mailto:guidal@ipno.in2p3.fr" target="_blank">guidal@ipno.in2p3.fr</a><br>
***<br></div></div><span>
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