Hi g12,<br>I have updated the diff c-s analysis for g p --> Lambda K+ on the <a href="http://clasweb.jlab.org/rungroups/g12/wiki/index.php/G12_Xi_Paper_-_Lambda_Cross_Sections">wiki page here</a>. The pertinent plot is here: <a href="http://clasweb.jlab.org/rungroups/g12/wiki/images/b/b2/Goetz_2012.09.13_lambda_dcs_1d.png">Lambda K+ diff c-s plot</a> where I have overlayed McCracken's data (orange area) on my own points (green errorbars). All major over-all scaling factors I used to get this results are discussed on the wiki page. Previous plots I showed did not have a factor (1/0.64) for the BR of Lambda --> p pi-; this is now included. However, there are factors still missing/unaccounted for -- listed here in possible order of effect on result:<br>
1. I did not take into account Lambda decaying outside the start counter.<br> effect on diff c-s: about +15%? (cos(theta) and sqrt(s) dependent)<br> 2. The reconstruction inefficiency (or trigger, or whatever you want to call this) of 16% is contrived and taken directly from g11a analyses. I believe this value may have been for two-track events (not three which is what I have here since I *require* the K+, p and pi- to all have a ST hit).<br>
effect on diff c-s: +/- 5-7%<br> 3. The trigger boundary at around sqrt(s) = 2.75 GeV needs to be addressed. This should either increase acceptance below the boundary or decrease acceptance above. This might cancel out 1. above for events below.<br>
<br>My current plan is to investigate 1, then 2, then 3 above.<br>--<br>Johann.<br>