<html><head></head><body><div dir="auto">Hi Andy,<br><br></div>
<div dir="auto">Can you elaborate why its not correct to add the systematic in quadrature with the statistical? <br></div>
<div dir="auto">I am not sure I understand why this "uses data that dont represent the experiment". Maybe we can talk more during the g14 meeting.<br><br></div>
<div dir="auto">Nick</div>
<div class="gmail_quote" >On Nov 7, 2017, at 22:22, "Dr. A.M. Sandorfi" <<a href="mailto:sandorfi@jlab.org" target="_blank">sandorfi@jlab.org</a>> wrote:<blockquote class="gmail_quote" style="margin: 0pt 0pt 0pt 0.8ex; border-left: 1px solid rgb(204, 204, 204); padding-left: 1ex;">
<pre class="blue">Hi Eugene,<br><br>Yes, your point is well taken - for those data points where the asymmetry is<br>very close to zero. One has two choices: we could either give an overall<br>fractional (%) uncertainty, while quoting the absolute value as an exception<br>when the asymmetry vanishes, or just quote only an absolute uncertainty for<br>all points. <br><br>The trouble comes at the subsequent stage when the data is used by the<br>various PWA groups. All PWA groups have their fitting routines set up to<br>float the scale of a data set while including a chi^2 penalty that is<br>weighted by a fractional systematic error. If we give them a systematic<br>uncertainty that is absolute, they will combine it in quadrature with the<br>statistical error to create an inflated point by point uncertainty, and set<br>the fitting scale to 1. I can guarantee that this will happen and it is a<br>completely incorrect way to use the data that doesn't represent the<br>experiment. So it is better to use the first approach - quote the systematic<br>uncertainty as a fractional (%) error, while explicitly noting the absolute<br>value of the systematic uncertainty for those asymmetry points with nearly<br>zero value. The later qualifying statement will probably be ignored in PWA<br>analyses, but at least most of the data will have been included properly.<br><br>Andy<br><br><br><br><br>On 11/4/17, 11:37 PM, "Eugene Pasyuk" <pasyuk@jlab.org> wrote:<br><br><blockquote class="gmail_quote" style="margin: 0pt 0pt 1ex 0.8ex; border-left: 1px solid #729fcf; padding-left: 1ex;"> <br> Any asymmetry can be anything between -1 and +1, 0 included. For any<br> observable which may be equal to 0 relative uncertainty does not make sense.<br> Only absolute uncertainty must be used.<br> The second term in Nick's equation is equal to 0 if ObservableValue is always<br> equal to 0 regardless of sigma_sys_relative. This is incorrect but good<br> illustration why one must not use relative uncertainty for asymmetries.<br> <br> -Eugene<br> <br> ----- Original Message -----<br><blockquote class="gmail_quote" style="margin: 0pt 0pt 1ex 0.8ex; border-left: 1px solid #ad7fa8; padding-left: 1ex;"> From: "Tsuneo Kageya" <kageya@jlab.org><br> To: "Nicholas Zachariou" <nicholas@jlab.org><br> Cc: "g14 run" <g14_run@jlab.org><br> Sent: Saturday, November 4, 2017 10:57:28 PM<br> Subject: Re: [G14_run] G14_run Digest, Vol 74, Issue 3 (Tuneo's question to<br> K Sigma analysis note)<br></blockquote> <br><blockquote class="gmail_quote" style="margin: 0pt 0pt 1ex 0.8ex; border-left: 1px solid #ad7fa8; padding-left: 1ex;"> Nick,<br> <br> thank you for the response.<br> I would like to know why the absolute is more appropriate.<br> I will look forward the statements.<br> <br> Regards, Tsuneo Kageya.<br> <br> ----- Original Message -----<br> From: "Nicholas Zachariou" <nicholas@jlab.org><br> To: "Tsuneo Kageya" <kageya@jlab.org><br> Cc: "g14 run" <g14_run@jlab.org><br> Sent: Saturday, November 4, 2017 3:23:46 PM<br> Subject: Re: [G14_run] G14_run Digest, Vol 74, Issue 3 (Tuneo's question to<br> K<br> Sigma analysis note)<br> <br> Hi Tsuneo,<br> <br> The absolute error is propagated directly to the total uncertainty<br> (sigma_tot=sqrt(sigma_sys_absolute^2+(ObservableValue*sigma_sys_relative)^2 +<br> sigma_statistical^2).<br> <br> I can elaborate more if you like on why thats the case (why absolute are more<br> appropriate in my case). I will include some statements in the note to<br> reflect<br> this.<br> <br> Let me know if you would like to discuss this more.<br> <br> Best regards,<br> Nick<br> <br> On Nov 4, 2017, 19:12, at 19:12, Tsuneo Kageya <kageya@jlab.org> wrote:<br><blockquote class="gmail_quote" style="margin: 0pt 0pt 1ex 0.8ex; border-left: 1px solid #8ae234; padding-left: 1ex;"> Hi Nick,<br> <br> Sorry to be late to make a question.<br> I have a question about the systematic error calculations.<br> <br> At page 35, on the table 4, you calculated the total absolute<br> systematic error<br> to be 0.10. How this is reflected into the total relative systematic<br> error ?<br> On the pi-p analysis, I think we calculated the systematic errors from<br> cuts in<br> the similar way and they are combined to the other errors (target and<br> beam polarizations).<br> Is this number 0.10 means 10 % or 0.1 % ?<br> <br> I may misunderstand this issue. Please let me know.<br> <br> Regards, Tsuneo Kageya.<br> <br> ----- Original Message -----<br> From: "g14 run-request" <g14_run-request@jlab.org><br> To: "g14 run" <g14_run@jlab.org><br> Sent: Saturday, November 4, 2017 12:00:03 PM<br> Subject: G14_run Digest, Vol 74, Issue 3<br> <br> Send G14_run mailing list submissions to<br> g14_run@jlab.org<br> <br> To subscribe or unsubscribe via the World Wide Web, visit<br> <a href="https://mailman.jlab.org/mailman/listinfo/g14_run">https://mailman.jlab.org/mailman/listinfo/g14_run</a><br> or, via email, send a message with subject or body 'help' to<br> g14_run-request@jlab.org<br> <br> You can reach the person managing the list at<br> g14_run-owner@jlab.org<br> <br> When replying, please edit your Subject line so it is more specific<br> than "Re: Contents of G14_run digest..."<br> <br> <br> Today's Topics:<br> <br> 1. Re: Updated Analysis Note (Reinhard Schumacher)<br> 2. Re: Updated Analysis Note (Nicholas Zachariou)<br> <br> <br><hr><br> <br> Message: 1<br> Date: Fri, 3 Nov 2017 22:19:24 -0400<br> From: Reinhard Schumacher <schumacher@cmu.edu><br> To: g14_run@jlab.org<br> Subject: Re: [G14_run] Updated Analysis Note<br> Message-ID: <a5780718-56ac-1dc0-44e8-6b991dbf849b@cmu.edu><br> Content-Type: text/plain; charset="windows-1252"; Format="flowed"<br> <br> Hi Nick,<br> <br> Indeed, noticeably improved.?? I recommend that you put the horizontal<br> error bars on Figs.? 29 - 32, too.? They are just as important there<br> since the model curves can vary a lot across one bin.<br> <br> Reinhard<br> <br> <br> On 11/3/2017 7:13 PM, Nicholas Zachariou wrote:<br><blockquote class="gmail_quote" style="margin: 0pt 0pt 1ex 0.8ex; border-left: 1px solid #fcaf3e; padding-left: 1ex;"> Dear all,<br> <br> I am attaching the updated note that incorporates and addresses all<br></blockquote> comments made. I have noticed that I have previously forgotten to<br> include the systematic uncertainty associated with the<br> photon-selection, and is now estimated and included.<br><blockquote class="gmail_quote" style="margin: 0pt 0pt 1ex 0.8ex; border-left: 1px solid #fcaf3e; padding-left: 1ex;"> I would like to thank again Shumacher for his time and valuable<br></blockquote> insight, and everybody for the comments and feedback. If there is no<br> other comments, I will be submitting the note early next week.<br><blockquote class="gmail_quote" style="margin: 0pt 0pt 1ex 0.8ex; border-left: 1px solid #fcaf3e; padding-left: 1ex;"> <br> Best regards,<br> Nick<br> <br> <br> <br> <br> <br> <br> <br><hr><br> G14_run mailing list<br> G14_run@jlab.org<br> <a href="https://mailman.jlab.org/mailman/listinfo/g14_run">https://mailman.jlab.org/mailman/listinfo/g14_run</a><br></blockquote> <br> --<br><hr><br> Reinhard Schumacher Department of Physics, 5000 Forbes Ave.<br> Carnegie Mellon University, Pittsburgh, PA 15213, U.S.A.<br> phone: 412-268-5177 web: <a href="http://www-meg.phys.cmu.edu/~schumach">www-meg.phys.cmu.edu/~schumach</a><br><hr><br> <br> -------------- next part --------------<br> An HTML attachment was scrubbed...<br> URL:<br> <<a href="https://mailman.jlab.org/pipermail/g14_run/attachments/20171103/651ca313/at">https://mailman.jlab.org/pipermail/g14_run/attachments/20171103/651ca313/at</a><br> tachment-0001.html><br> <br><hr><br> <br> Message: 2<br> Date: Sat, 04 Nov 2017 07:10:14 +0000<br> From: Nicholas Zachariou <nicholas@jlab.org><br> To: Reinhard Schumacher <schumacher@cmu.edu><br> Cc: G14 Run <g14_run@jlab.org><br> Subject: Re: [G14_run] Updated Analysis Note<br> Message-ID: <d21ed42f-6b13-482d-8c8b-4ea087ad31e1@jlab.org><br> Content-Type: text/plain; charset="utf-8"<br> <br> Hi Reinhard,<br> <br> The figures looked a bit busy when I did that (too many lines) and<br> thats why i left the x-uncertainties out in those, but its takes me 2<br> minutes to incorborate them. I think that will be more relevant when we<br> decide exactly how to present our results in the publication.<br> <br> In the meantime I was wondering if its OK with the group to share our<br> preliminary results with the theorists and see if we can get any<br> insights from them.<br> <br> Best regards,<br> Nick<br> <br> <br> On Nov 4, 2017, 02:19, at 02:19, Reinhard Schumacher<br> <schumacher@cmu.edu> wrote:<br><blockquote class="gmail_quote" style="margin: 0pt 0pt 1ex 0.8ex; border-left: 1px solid #fcaf3e; padding-left: 1ex;"> Hi Nick,<br> <br> Indeed, noticeably improved.?? I recommend that you put the horizontal<br></blockquote> <br><blockquote class="gmail_quote" style="margin: 0pt 0pt 1ex 0.8ex; border-left: 1px solid #fcaf3e; padding-left: 1ex;"> error bars on Figs.? 29 - 32, too.? They are just as important there<br> since the model curves can vary a lot across one bin.<br> <br> Reinhard<br> <br> <br> On 11/3/2017 7:13 PM, Nicholas Zachariou wrote:<br><blockquote class="gmail_quote" style="margin: 0pt 0pt 1ex 0.8ex; border-left: 1px solid #e9b96e; padding-left: 1ex;"> Dear all,<br> <br> I am attaching the updated note that incorporates and addresses all<br></blockquote> comments made. I have noticed that I have previously forgotten to<br> include the systematic uncertainty associated with the<br> photon-selection, and is now estimated and included.<br><blockquote class="gmail_quote" style="margin: 0pt 0pt 1ex 0.8ex; border-left: 1px solid #e9b96e; padding-left: 1ex;"> I would like to thank again Shumacher for his time and valuable<br></blockquote> insight, and everybody for the comments and feedback. If there is no<br> other comments, I will be submitting the note early next week.<br><blockquote class="gmail_quote" style="margin: 0pt 0pt 1ex 0.8ex; border-left: 1px solid #e9b96e; padding-left: 1ex;"> <br> Best regards,<br> Nick<br> <br> <br> <br> <br> <br> <br> <br><hr><br> G14_run mailing list<br> G14_run@jlab.org<br> <a href="https://mailman.jlab.org/mailman/listinfo/g14_run">https://mailman.jlab.org/mailman/listinfo/g14_run</a><br></blockquote> <br> --<br><hr><br> Reinhard Schumacher Department of Physics, 5000 Forbes Ave.<br> Carnegie Mellon University, Pittsburgh, PA 15213, U.S.A.<br> phone: 412-268-5177 web: <a href="http://www-meg.phys.cmu.edu/~schumach">www-meg.phys.cmu.edu/~schumach</a><br><hr><br> <br> <br> <br><hr><br> <br><hr><br> G14_run mailing list<br> G14_run@jlab.org<br> <a href="https://mailman.jlab.org/mailman/listinfo/g14_run">https://mailman.jlab.org/mailman/listinfo/g14_run</a><br></blockquote> -------------- next part --------------<br> An HTML attachment was scrubbed...<br> URL:<br> <<a href="https://mailman.jlab.org/pipermail/g14_run/attachments/20171104/14965baf/at">https://mailman.jlab.org/pipermail/g14_run/attachments/20171104/14965baf/at</a><br> tachment-0001.html><br> <br><hr><br> <br> Subject: Digest Footer<br> <br><hr><br> G14_run mailing list<br> G14_run@jlab.org<br> <a href="https://mailman.jlab.org/mailman/listinfo/g14_run">https://mailman.jlab.org/mailman/listinfo/g14_run</a><br> <br> <br><hr><br> <br> End of G14_run Digest, Vol 74, Issue 3<br> **************************************<br><hr><br> G14_run mailing list<br> G14_run@jlab.org<br> <a href="https://mailman.jlab.org/mailman/listinfo/g14_run">https://mailman.jlab.org/mailman/listinfo/g14_run</a><br></blockquote><hr><br> G14_run mailing list<br> G14_run@jlab.org<br> <a href="https://mailman.jlab.org/mailman/listinfo/g14_run">https://mailman.jlab.org/mailman/listinfo/g14_run</a><br></blockquote><hr><br> G14_run mailing list<br> G14_run@jlab.org<br> <a href="https://mailman.jlab.org/mailman/listinfo/g14_run">https://mailman.jlab.org/mailman/listinfo/g14_run</a><br></blockquote><br><br><hr><br>G14_run mailing list<br>G14_run@jlab.org<br><a href="https://mailman.jlab.org/mailman/listinfo/g14_run">https://mailman.jlab.org/mailman/listinfo/g14_run</a><br></pre></blockquote></div></body></html>