<html xmlns="http://www.w3.org/TR/REC-html40" xmlns:m="http://schemas.microsoft.com/office/2004/12/omml" xmlns:w="urn:schemas-microsoft-com:office:word" xmlns:o="urn:schemas-microsoft-com:office:office" xmlns:v="urn:schemas-microsoft-com:vml"><head></head><body vlink="purple" link="blue" lang="EN-US"><div class="WordSection1"><p class="MsoNormal">Hi Johann,<o:p></o:p></p><p class="MsoNormal"><o:p> </o:p></p><p class="MsoNormal">It looks like your cross sections are still about a factor of 2 too low, but this is clearly an improvement over previous attempts.<o:p></o:p></p><p class="MsoNormal"><o:p> </o:p></p><p class="MsoNormal">The acceptance looks particularly scattered, probably due to low statistics. Can you improve this by running more GSIM?<o:p></o:p></p><p class="MsoNormal"><o:p> </o:p></p><p class="MsoNormal">It’s a bit tricky to get a correct total cross section without taking small bin sizes in angle and then fitting the angular distribution <o:p></o:p></p><p class="MsoNormal">to extrapolate into the unmeasured regions of CLAS (such as near the beamline at forward angles). It’s likely that the cross <o:p></o:p></p><p class="MsoNormal">sections will look better after more work.<o:p></o:p></p><p class="MsoNormal"><o:p> </o:p></p><p class="MsoNormal">Ken<o:p></o:p></p><p class="MsoNormal"><o:p> </o:p></p><div><p class="MsoNormal"><b>From:</b> g12-bounces@jlab.org [mailto:g12-bounces@jlab.org] <b>On Behalf Of </b>Johann Goetz<br><b>Sent:</b> Friday, August 19, 2011 4:29 PM<br><b>To:</b> g12<br><b>Subject:</b> [G12] Lambda Total Cross Section update.<o:p></o:p></p></div><p class="MsoNormal"><o:p> </o:p></p><p class="MsoNormal">Hi g12,<br>I couldn't get this done before the last meeting, but I did a rough total cross section measurement using the most recent gflux data and everything looks pretty good so far. There are a few issues I still need to address, but after certain corrections (the trigger for example) I believe we will have good agreement with older results from CLAS/g1 and SAPHIR.<br><br><a href="http://clasweb.jlab.org/rungroups/g12/wiki/index.php/G12_Xi_Paper_-_Lambda_Cross_Sections">Here is a link to the plots on the g12 wiki</a><br><br>I used 93 complete runs that were evenly distributed throughout g12 - all production runs (no single sector runs).<br><br>Please mull this over and get back to me with questions on Monday and I can investigate further before the next meeting.<br>Have a good weekend everyone!<br>-- <br>Johann T. Goetz, PhD.<br><a href="mailto:jgoetz@ucla.edu">jgoetz@ucla.edu</a><br>Nefkens Group, UCLA Dept. of Physics & Astronomy<br>Hall-B, Jefferson Lab, Newport News, VA<br>Office: 757-269-5465 (CEBAF Center F-335)<br>Mobile: 757-768-9999<o:p></o:p></p></div></body></html>