Message-ID: <4AEF6385.3090805@jlab.org> Date: Mon, 02 Nov 2009 17:56:05 -0500 From: Seamus Riordan User-Agent: Thunderbird 2.0.0.23 (X11/20090817) MIME-Version: 1.0 To: Bogdan Wojtsekhowski , Gordon Cates , Nilanga Liyanage Subject: Present Content-Type: text/plain; charset=ISO-8859-1 Content-Transfer-Encoding: 7bit Hi everyone, Bogdan asked me to send these around. They're basically the current best representation of GEn we have at the moment. They're still subject to change as I go through the final review of our analysis. GEn values are quoted as GEn +/- stat err +/- total systematic error For reference I have also included Q^2, the relative statistical error and the relative error contributed from the Monte Carlo. This is done for our normal cuts and wide cuts, and on Bogdan's request again with 1.3 times the inelastics from the Monte Carlo to get a sense of the stability. normal cut GEn 0.018000 +/- 0.002951 +/- 0.001687 Q^2 = , dstat/GEn = 0.164, dMC/GEn = 0.034 wide cut GEn 0.017904 +/- 0.002331 +/- 0.002308 Q^2 = , dstat/GEn = 0.130, dMC/GEn = 0.096 1.3*inelastic cut GEn 0.018348 +/- 0.003068 +/- 0.001824 Q^2 = , dstat/GEn = 0.167, dMC/GEn = 0.050 1.3*inelastic, wide GEn 0.018521 +/- 0.002525 +/- 0.002958 Q^2 = , dstat/GEn = 0.134, dMC/GEn = 0.133 So the total error goes down, but not by as much as we would like. It should improve a little with my better estimate of the Monte Carlo error (I'll have some more details at the Wednesday meeting on this). I'll see what I can do about varying the cuts to optimize this contribution. Also, the present numbers I have for the other two points using the standard cuts: Q^2 = 1.7 GeV^2, GEn 0.025666 +/- 0.001889 +/- 0.002655 Q^2 = 2.5 GeV^2, GEn 0.021560 +/- 0.002604 +/- 0.002297 For reference, the numbers we usually show on our GEn prelimary plots (with 0.86 neutron polarization, NO FSI): Q^2 GEn stat sys 1.72 3.17e-02 2.1E-03 2.9E-03 2.5 1.72e-02 2.8E-03 2.0E-03 3.47 1.09e-02 2.6E-03 8.0E-04 Seamus -- Dr. Seamus P. Riordan riordan@jlab.org University of Virginia Office: (757) 269-6037 Post-doctoral Research Associate Pager: (757) 584-0051 CEBAF Center F206, Jefferson Laboratory 12000 Jefferson Ave. Newport News, VA 23606