Date: Mon, 20 Dec 2010 16:00:18 -0800 From: J. Va'vra Subject: A comparison Hello guys, I wanted to do this a long time ago, but got to it now. I compared results of three different analysis for the beam test data, either for (a) all pixels, or (b) slot 3 only. It is not easy to compare them by a eye. I tried to use the same color of connecting lines for each relevant group. Some methods agree some disagree. It does show a certain systematic error, and it appears to be at a level of 1-2 mrads. The worst disagreement is for uncorrected resolution. It probably resulted from our different treatment of the background under the peak. I did include also the TOP only analysis. I know we do not consider this method as relevant as it assumes beta = 1. However, for each PID hypothesis we do assume a mass, and therefore the beta as we measure a momentum. Anyway, TOPe will be used together with pixels in FDIRC, and this plot suggests that it might end up to be equal weight for longer paths. Regards, Jerry ***************************************************************** J. Va'vra Bin 62, S.L.A.C., 2575 Sand Hill Road, Menlo Park, CA 94025, U.S.A. Tel. 650-926-2658 Fax: 650-926-4178 e-mail: jjv@slac.stanford.edu home page: http://www.slac.stanford.edu/~jjv *****************************************************************