<html><head><meta http-equiv="Content-Type" content="text/html charset=us-ascii"></head><body style="word-wrap: break-word; -webkit-nbsp-mode: space; -webkit-line-break: after-white-space; "><div>Steve stopped by and was asking about our proposal. I explained to him where we were at and he is going to join the meeting today.</div><div><br></div><div>
<div style="color: rgb(0, 0, 0); font-family: Optima; font-size: medium; font-style: normal; font-variant: normal; font-weight: normal; letter-spacing: normal; line-height: normal; orphans: 2; text-align: -webkit-auto; text-indent: 0px; text-transform: none; white-space: normal; widows: 2; word-spacing: 0px; -webkit-text-size-adjust: auto; -webkit-text-stroke-width: 0px; word-wrap: break-word; -webkit-nbsp-mode: space; -webkit-line-break: after-white-space; ">Patricia<br><br>-- <br>Patricia SOLVIGNON<br>Staff Scientist<br>Jefferson Lab<br><br>Current address : <br>Jefferson Lab<br>Suite 6, MS. 12H4 Room C121 (Cebaf Center)<br>12000 Jefferson Avenue Office: (757)-269-6933<br>Newport News, VA 23606</div>
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<br><div><div>On May 1, 2013, at 10:55 AM, Dustin Keller <<a href="mailto:dustin@jlab.org">dustin@jlab.org</a>> wrote:</div><br class="Apple-interchange-newline"><blockquote type="cite">any time for me, 2 is good<br><br>dustin<br><br>On Wed, 1 May 2013, Karl Slifer wrote:<br><br><blockquote type="cite">OK,<br><br>I think 1/2 hour is not sufficient, so how about 2:00pm. (I'll skip my<br>student office hours.)<br><br>JP?<br>Dustin?<br>Oscar?<br><br>Ellie and Patricia have already said they are free this time, and anytime<br>today is unfortunately difficult for Narbe.<br><br>thanks<br><br>-Karl<br><br><br><br>On Wed, May 1, 2013 at 10:40 AM, Oscar Rondon-Aramayo <<br><a href="mailto:or@cms.mail.virginia.edu">or@cms.mail.virginia.edu</a>> wrote:<br><br><blockquote type="cite">Hi Karl,<br><br>We met with Dustin last evening and after going in detail over the<br>formulas<br>for the ratio Npol/Nun, we found that the unpolarized sigma_N, sigma_D and<br>sigma_He (see my last email) can be collected in one group, which cancels<br>with the denominator (all unpolarized), leaving a term<br>sigma_D*Azz*Pzz/denominator, which I realized can be written as f*Azz*Pzz,<br>f<br>= dilution factor.<br><br>With the dilution factor, the formulas in Dustin's third row of equalities<br>in his Observables2 report, which are valid only for pure D (the HERMES<br>case), can also be used for ND3 targets.<br><br>In summary, we can take the ratio of the pol to unpol counts, which takes<br>us<br>to Azz, at the price of the dilution factor and its error, plus the need to<br>use some form of F1 to get b1 from Azz, or the difference, which takes us<br>directly to b1.<br><br>In both cases the systematic errors, other than the charge and detector<br>efficiency are normalizations, and since the error on Pzz is expected to<br>dominate, it really is a matter of taste, once we have the numbers on hand.<br>We'll surely try both.<br><br>For the statistical errors, f enters in the Azz time estimate, but Q*A*l*pf<br>enter in the difference (Pzz is in both). I need to do some numbers yet<br>(everyone should try) to compare the two approaches.<br><br>Finally, today we have the SANE meeting at 3:30, so I can join b1 from 1:00<br>to 3:30.<br><br>Cheers,<br><br>Oscar<br><br>On Wed, 1 May 2013 09:18:48 -0400<br> Karl Slifer <<a href="mailto:karl.slifer@unh.edu">karl.slifer@unh.edu</a>> wrote:<br><blockquote type="cite">Hi all,<br><br>The methodology is the central question and I think we have to resolve<br></blockquote>any<br><blockquote type="cite">lingering doubts today. I highly encourage that everyone really read<br>Oscar's note (Eq 19 and 20) and his last email before we discuss today.<br><br>I would really not like to delay till tomorrow if possible since time is<br>so<br>tight. I hope we can get a majority to participate at 3pm. Please let me<br>know if you can't.<br><br>-Karl<br><br><br><br>---<br>Karl J. Slifer<br>Assistant Professor<br>University of New Hampshire<br>Telephone : 603-722-0695<br><br><br>On Tue, Apr 30, 2013 at 5:59 PM, O. A. Rondon <<a href="mailto:or@virginia.edu">or@virginia.edu</a>> wrote:<br><br><blockquote type="cite">Hi Dustin,<br><br>Dustin Keller wrote:<br><blockquote type="cite">You can only benefit from the systematic reduction if you us Azz as<br>discussed yesterday. But at this point I am not partial.<br><br>dustin<br><br></blockquote><br>In the experiment, we only have counts. What we need to show to the PAC<br>is how we go from the counts Npol and Nu, to Azz or b1. A measured<br>quantity needs to be on one side and physics on the other. Lets say we<br>start with your ratio Npol/Nu - 1 = Pzz*Azz, which only requires Pzz >0.<br><br>We need to prove that the lhs reproduces the rhs. We have, in general,<br>N = Q*e*A*l*sigma. But since N are counts from everything in the target,<br>it is not a simple matter of canceling quantities that stay the same<br>when the polarization changes:<br><br>Npol = Qpol*epol*Apol*lpol*sigma_pol<br> = Qpol*epol*Apol*lpol*[(sigma_N+3*sigma_Dpol)*pf + sigma_He*(1-pf)]<br><br>Nu = Qu*eu*Au*lu*[(sigma_N+3*sigma_D)*pf + sigma_He*(1-pf)]<br><br>sigma_N and sigma_He are the same, always unpol. And<br>sigma_Dpol = sigma_D(1+Pzz*Azz).<br><br>Then, since Apol = Au = A, and lpol = lu = l,<br><br>Npol/Nu =<br>(Qpol/Qu)*(epol/eu)*[(sigma_N+3sigma_D(1+ Azz*Pzz))*pf+..)]/[(sigma_N+..<br><br>where I just put ..., because I don't see how it can be simplified to<br>just leave Azz*Pzz + 1, to equal the rhs.<br><br>On the other hand, if instead of taking the ratio Npol/Nu first, we take<br>the difference first, it's indeed possible to isolate the required<br>Pzz*b1 on on side, like I do in my draft, eq. (19) or (20). And in<br>fact, we don't even need to bother with Azz, because we get b1 without<br>having to multiply Azz by F1, introducing one more systematic error.<br><br>So, in summary, once one substitutes all the ingredients for your sigmas<br>we get, or ought to get, eq.(19) or (20) back.<br><br>In both of those equations, the systematics for Pzz, A, and l(pf) are<br>normalization factors, just like we want them to be, for control of<br>systematics, but the charge and the detector efficiency are not common<br>factors, they depend on the period when the data are taken, either pol.<br>or unpol.<br><br>My point is that for the proposal, we must spell this all out, to give<br>explicit sources of errors, and to calculate times or statistical errors<br>correctly. For example, the statistical error must be sqrt(Npol + N_U) ~<br>sqrt(2N), because it is just the error of a difference, etc.<br><br>We need to have a consensus on how the method is going to be described<br>in the proposal, which needs to be done in the most precise way to avoid<br>any confusion due to ambiguities.<br><br>Cheers,<br><br>Oscar<br><br><br><blockquote type="cite">On Tue, 30 Apr 2013, O. A. Rondon wrote:<br><br><blockquote type="cite">Hi,<br><br>Since I couldn't stay until the end of the meeting, and I don't think<br>there will be minutes of it, I would like to share some ideas for the<br>proposal draft.<br><br>Basically, what we need is an equation with the measured quantity on<br></blockquote></blockquote>one<br><blockquote type="cite"><blockquote type="cite">side and b1 or Azz on the other. Based on what I think the consensus<br>was, to measure polarized minus unpolarized counts on a single cup<br></blockquote></blockquote></blockquote></blockquote>with<br><blockquote type="cite"><blockquote type="cite"><blockquote type="cite"><blockquote type="cite">the target field aligned along the beam, I've updated the draft of my<br>method, see subsection 0.2, which discusses this. Eq. (19) or eq.<br></blockquote></blockquote></blockquote></blockquote>(20)<br><blockquote type="cite"><blockquote type="cite"><blockquote type="cite"><blockquote type="cite">meet the conditions stated above. This is the approach I would<br></blockquote></blockquote>subscribe<br><blockquote type="cite"><blockquote type="cite">to, unless there is another version that is shown to also represent<br></blockquote></blockquote></blockquote></blockquote>the<br><blockquote type="cite"><blockquote type="cite"><blockquote type="cite"><blockquote type="cite">procedure, which should be circulated as soon as possible. The draft<br>is here<br><a href="http://twist.phys.virginia.edu/~or/b1/b1_method-v2.pdf">http://twist.phys.virginia.edu/~or/b1/b1_method-v2.pdf</a><br><br>Cheers,<br><br>Oscar<br><br>_______________________________________________<br>b1_ana mailing list<br>b1_ana@jlab.org<br>https://mailman.jlab.org/mailman/listinfo/b1_ana<br><br></blockquote><br></blockquote><br><br><br><br><br><br><br><br><br><br><br><br><br><br><br><br><br>_______________________________________________<br>b1_ana mailing list<br><a href="mailto:b1_ana@jlab.org">b1_ana@jlab.org</a><br>https://mailman.jlab.org/mailman/listinfo/b1_ana<br><br></blockquote></blockquote><br>_______________________________________________<br>b1_ana mailing list<br><a href="mailto:b1_ana@jlab.org">b1_ana@jlab.org</a><br>https://mailman.jlab.org/mailman/listinfo/b1_ana<br><br></blockquote><br></blockquote>_______________________________________________<br>b1_ana mailing list<br><a href="mailto:b1_ana@jlab.org">b1_ana@jlab.org</a><br>https://mailman.jlab.org/mailman/listinfo/b1_ana<br></blockquote></div><br></body></html>