<html><head></head><body style="word-wrap: break-word; -webkit-nbsp-mode: space; -webkit-line-break: after-white-space; ">Yes, we are also using JPAC models (ie. of omega decay and old production measurements) to interact over the acceptance corrections. However, we just need the systematics to be<div>smaller than the signal to be extract to make the process to work. Depends on a given analysis.</div><div><br><div><div>On Jul 12, 2016, at 4:29 PM, Lei Guo wrote:</div><br class="Apple-interchange-newline"><blockquote type="cite"><meta http-equiv="Content-Type" content="text/html charset=utf-8"><div style="word-wrap: break-word; -webkit-nbsp-mode: space; -webkit-line-break: after-white-space;" class="">I agree. Pluto is something multiple people in g12 are using to feed the cross sections back to the generator. Maybe this is something to consider. <div class=""><br class=""><div apple-content-edited="true" class="">
<div class=""><div class=""><div class="">Lei Guo</div><div class="">Assistant Professor</div><div class="">Physics Department</div><div class="">Florida International University</div><div class="">Miami, FL</div></div><div class=""><br class=""></div><div class="">email: <a href="mailto:leguo@fiu.edu" class="">leguo@fiu.edu</a> or <a href="mailto:lguo@jlab.org" class="">lguo@jlab.org</a></div><div class="">Office:305-348-0234</div></div>
</div>
<br class=""><div><blockquote type="cite" class=""><div class="">On Jul 12, 2016, at 4:26 PM, Eugene Pasyuk <<a href="mailto:pasyuk@jlab.org" class="">pasyuk@jlab.org</a>> wrote:</div><br class="Apple-interchange-newline"><div class=""><span style="font-family: Helvetica; font-size: 12px; font-style: normal; font-variant: normal; font-weight: normal; letter-spacing: normal; line-height: normal; orphans: auto; text-align: start; text-indent: 0px; text-transform: none; white-space: normal; widows: auto; word-spacing: 0px; -webkit-text-stroke-width: 0px; float: none; display: inline !important;" class="">There is a well known approach how to minimize uncertainties in the acceptance if acceptance depends on physics particularly for multiparticle final states and even if you have holes in the acceptance. People use iterative procedure. If you have "realistic" model of your reaction you use event generator based on this model to calculate the acceptance. Then you extract physics distributions using this acceptance. Then you modify your event generator according to your experimental distribution and calculate new acceptance. With updated acceptance you extract updated experimental distributions again and so on. This procedure converges to something. This would be the best you can get. If you don't have "realistic" model to start with, you start with phase space generator. Eventually this will converge too but likely will need more iterations. Yes, you have to run gsim several times and it is CPU intensive.</span><br style="font-family: Helvetica; font-size: 12px; font-style: normal; font-variant: normal; font-weight: normal; letter-spacing: normal; line-height: normal; orphans: auto; text-align: start; text-indent: 0px; text-transform: none; white-space: normal; widows: auto; word-spacing: 0px; -webkit-text-stroke-width: 0px;" class=""><span style="font-family: Helvetica; font-size: 12px; font-style: normal; font-variant: normal; font-weight: normal; letter-spacing: normal; line-height: normal; orphans: auto; text-align: start; text-indent: 0px; text-transform: none; white-space: normal; widows: auto; word-spacing: 0px; -webkit-text-stroke-width: 0px; float: none; display: inline !important;" class="">There is no universal acceptance correction that fits all. This is why in g12 review we deferred acceptance/efficiency to individual analysis reviews.</span><br style="font-family: Helvetica; font-size: 12px; font-style: normal; font-variant: normal; font-weight: normal; letter-spacing: normal; line-height: normal; orphans: auto; text-align: start; text-indent: 0px; text-transform: none; white-space: normal; widows: auto; word-spacing: 0px; -webkit-text-stroke-width: 0px;" class=""><br style="font-family: Helvetica; font-size: 12px; font-style: normal; font-variant: normal; font-weight: normal; letter-spacing: normal; line-height: normal; orphans: auto; text-align: start; text-indent: 0px; text-transform: none; white-space: normal; widows: auto; word-spacing: 0px; -webkit-text-stroke-width: 0px;" class=""><span style="font-family: Helvetica; font-size: 12px; font-style: normal; font-variant: normal; font-weight: normal; letter-spacing: normal; line-height: normal; orphans: auto; text-align: start; text-indent: 0px; text-transform: none; white-space: normal; widows: auto; word-spacing: 0px; -webkit-text-stroke-width: 0px; float: none; display: inline !important;" class="">-Eugene</span><br style="font-family: Helvetica; font-size: 12px; font-style: normal; font-variant: normal; font-weight: normal; letter-spacing: normal; line-height: normal; orphans: auto; text-align: start; text-indent: 0px; text-transform: none; white-space: normal; widows: auto; word-spacing: 0px; -webkit-text-stroke-width: 0px;" class=""><br style="font-family: Helvetica; font-size: 12px; font-style: normal; font-variant: normal; font-weight: normal; letter-spacing: normal; line-height: normal; orphans: auto; text-align: start; text-indent: 0px; text-transform: none; white-space: normal; widows: auto; word-spacing: 0px; -webkit-text-stroke-width: 0px;" class=""><span style="font-family: Helvetica; font-size: 12px; font-style: normal; font-variant: normal; font-weight: normal; letter-spacing: normal; line-height: normal; orphans: auto; text-align: start; text-indent: 0px; text-transform: none; white-space: normal; widows: auto; word-spacing: 0px; -webkit-text-stroke-width: 0px; float: none; display: inline !important;" class="">----- Original Message -----</span><br style="font-family: Helvetica; font-size: 12px; font-style: normal; font-variant: normal; font-weight: normal; letter-spacing: normal; line-height: normal; orphans: auto; text-align: start; text-indent: 0px; text-transform: none; white-space: normal; widows: auto; word-spacing: 0px; -webkit-text-stroke-width: 0px;" class=""><blockquote type="cite" style="font-family: Helvetica; font-size: 12px; font-style: normal; font-variant: normal; font-weight: normal; letter-spacing: normal; line-height: normal; orphans: auto; text-align: start; text-indent: 0px; text-transform: none; white-space: normal; widows: auto; word-spacing: 0px; -webkit-text-stroke-width: 0px;" class="">From: "Michael Paolone" <<a href="mailto:mpaolone@jlab.org" class="">mpaolone@jlab.org</a>><br class="">To: "Carlos Salgado" <<a href="mailto:salgado@jlab.org" class="">salgado@jlab.org</a>><br class="">Cc: "<a href="mailto:g12@jlab.org" class="">g12@jlab.org</a> <a href="mailto:g12@jlab.org" class="">g12@jlab.org</a>" <<a href="mailto:g12@jlab.org" class="">g12@jlab.org</a>><br class="">Sent: Tuesday, July 12, 2016 4:02:52 PM<br class="">Subject: Re: [G12] Target Position<br class=""></blockquote><br style="font-family: Helvetica; font-size: 12px; font-style: normal; font-variant: normal; font-weight: normal; letter-spacing: normal; line-height: normal; orphans: auto; text-align: start; text-indent: 0px; text-transform: none; white-space: normal; widows: auto; word-spacing: 0px; -webkit-text-stroke-width: 0px;" class=""><blockquote type="cite" style="font-family: Helvetica; font-size: 12px; font-style: normal; font-variant: normal; font-weight: normal; letter-spacing: normal; line-height: normal; orphans: auto; text-align: start; text-indent: 0px; text-transform: none; white-space: normal; widows: auto; word-spacing: 0px; -webkit-text-stroke-width: 0px;" class="">Continuing on the same train of thought: there are also many methods to<br class="">interpolate or extrapolate across "holes" in kinematic variables, from<br class="">simple splines to more complicated multi-dimensional machine learning<br class="">techniques. Unfortunately, there will always be a systematic uncertainty<br class="">cost that is technique dependent, but it is something to consider.<br class=""><br class="">-Michael<br class=""><br class=""><blockquote type="cite" class="">Volker et al<br class=""><br class="">I agree with you that we can not correct zero acceptance regions. (This is<br class="">similar to correct the missing corners of the x:y plots from Chris and<br class="">Andres).<br class="">and we will have to live with that uncertainty (systematic) and just<br class="">consider the regions of non-zero acceptance. In cross-sections, this<br class="">will introduce a large uncertainty at low energies.<br class=""><br class="">Just to remind everyone, g12 was proposed (and running conditions chosen)<br class="">to look for diffractive produced (forward) mesons (exotics) at beam<br class="">energies > 4.4 GeV.<br class=""><br class="">-Carlos<br class=""><br class="">On Jul 12, 2016, at 3:25 PM, Volker Crede wrote:<br class=""><br class=""><blockquote type="cite" class="">For the ω channel, Zulkaida found that we are loosing almost the full<br class="">c.m. backward region of the charged pions if the reaction happens along<br class="">the first few centimeters of the photon interacting with the target.<br class="">This intensity of the cross section is essentially lost when we<br class="">integrate over these zero-acceptance regions. And this introduces the<br class="">large uncertainty.<br class=""><br class="">We found the effect for pππ (missing π) but it is likely happening as<br class="">well for pππ (missing η). The effect may be reduced at high energies.<br class="">And g11a does not show these zero-acceptance holes since the target was<br class="">centered.<br class=""><br class="">- Volker<br class=""><br class=""><br class="">On Jul 12, 2016, at 2:29 PM, "Michael C. Kunkel" <<a href="mailto:mkunkel@jlab.org" class="">mkunkel@jlab.org</a>><br class="">wrote:<br class=""><br class=""><blockquote type="cite" class="">Greetings,<br class=""><br class="">The efficiency map is binned in z, p, theta and phi. However, Volker is<br class="">correct about the zero acceptance regions postulate.<br class=""><br class="">BR<br class="">MK<br class="">----------------------------------------<br class="">Michael C. Kunkel, PhD<br class="">Forschungszentrum Jülich<br class="">Nuclear Physics Institute and Juelich Center for Hadron Physics<br class="">Experimental Hadron Structure (IKP-1)<br class=""><a href="http://www.fz-juelich.de/ikp" class="">www.fz-juelich.de/ikp</a><br class=""><br class="">On 7/12/16 8:21 PM, Volker Crede wrote:<br class=""><blockquote type="cite" class=""><br class="">However, it does not solve the acceptance problem when it comes to<br class="">reconstructing a meson from its decay products. The best efficiency<br class="">map does not know the physics in zero-acceptance regions.<br class=""></blockquote><br class="">_______________________________________________<br class="">G12 mailing list<br class=""><a href="mailto:G12@jlab.org">G12@jlab.org</a><br class="">https://mailman.jlab.org/mailman/listinfo/g12<br class=""></blockquote><br class=""><br class=""><br class=""><br class=""><br class=""><br class="">_______________________________________________<br class="">G12 mailing list<br class=""><a href="mailto:G12@jlab.org" class="">G12@jlab.org</a><br class=""><a href="https://mailman.jlab.org/mailman/listinfo/g12">https://mailman.jlab.org/mailman/listinfo/g12</a><br class=""></blockquote><br class=""><br class="">_______________________________________________<br class="">G12 mailing list<br class=""><a href="mailto:G12@jlab.org" class="">G12@jlab.org</a><br class=""><a href="https://mailman.jlab.org/mailman/listinfo/g12">https://mailman.jlab.org/mailman/listinfo/g12</a><br class=""><br class=""></blockquote><br class=""><br class="">_______________________________________________<br class="">G12 mailing list<br class=""><a href="mailto:G12@jlab.org" class="">G12@jlab.org</a><br class=""><a href="https://mailman.jlab.org/mailman/listinfo/g12">https://mailman.jlab.org/mailman/listinfo/g12</a><br class=""></blockquote><br style="font-family: Helvetica; font-size: 12px; font-style: normal; font-variant: normal; font-weight: normal; letter-spacing: normal; line-height: normal; orphans: auto; text-align: start; text-indent: 0px; text-transform: none; white-space: normal; widows: auto; word-spacing: 0px; -webkit-text-stroke-width: 0px;" class=""><span style="font-family: Helvetica; font-size: 12px; font-style: normal; font-variant: normal; font-weight: normal; letter-spacing: normal; line-height: normal; orphans: auto; text-align: start; text-indent: 0px; text-transform: none; white-space: normal; widows: auto; word-spacing: 0px; -webkit-text-stroke-width: 0px; float: none; display: inline !important;" class="">_______________________________________________</span><br style="font-family: Helvetica; font-size: 12px; font-style: normal; font-variant: normal; font-weight: normal; letter-spacing: normal; line-height: normal; orphans: auto; text-align: start; text-indent: 0px; text-transform: none; white-space: normal; widows: auto; word-spacing: 0px; -webkit-text-stroke-width: 0px;" class=""><span style="font-family: Helvetica; font-size: 12px; font-style: normal; font-variant: normal; font-weight: normal; letter-spacing: normal; line-height: normal; orphans: auto; text-align: start; text-indent: 0px; text-transform: none; white-space: normal; widows: auto; word-spacing: 0px; -webkit-text-stroke-width: 0px; float: none; display: inline !important;" class="">G12 mailing list</span><br style="font-family: Helvetica; font-size: 12px; font-style: normal; font-variant: normal; font-weight: normal; letter-spacing: normal; line-height: normal; orphans: auto; text-align: start; text-indent: 0px; text-transform: none; white-space: normal; widows: auto; word-spacing: 0px; -webkit-text-stroke-width: 0px;" class=""><a href="mailto:G12@jlab.org" style="font-family: Helvetica; font-size: 12px; font-style: normal; font-variant: normal; font-weight: normal; letter-spacing: normal; line-height: normal; orphans: auto; text-align: start; text-indent: 0px; text-transform: none; white-space: normal; widows: auto; word-spacing: 0px; -webkit-text-stroke-width: 0px;" class="">G12@jlab.org</a><br style="font-family: Helvetica; font-size: 12px; font-style: normal; font-variant: normal; font-weight: normal; letter-spacing: normal; line-height: normal; orphans: auto; text-align: start; text-indent: 0px; text-transform: none; white-space: normal; widows: auto; word-spacing: 0px; -webkit-text-stroke-width: 0px;" class=""><a href="https://mailman.jlab.org/mailman/listinfo/g12" style="font-family: Helvetica; font-size: 12px; font-style: normal; font-variant: normal; font-weight: normal; letter-spacing: normal; line-height: normal; orphans: auto; text-align: start; text-indent: 0px; text-transform: none; white-space: normal; widows: auto; word-spacing: 0px; -webkit-text-stroke-width: 0px;" class="">https://mailman.jlab.org/mailman/listinfo/g12</a></div></blockquote></div><br class=""></div></div>_______________________________________________<br>G12 mailing list<br><a href="mailto:G12@jlab.org">G12@jlab.org</a><br>https://mailman.jlab.org/mailman/listinfo/g12<br></blockquote></div><br></div></body></html>