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Hi all, reading the bad and looking for more useful plots has been an intresting work. With Concezio I have investigated the nature of the discontinuities in the relevant plots which we use for the optimization. Now, with an improved fit to the Mx residual distribution, the distributions are much more reliable: see for Vub (fit -80MeV- ; mean distribu.; sig distr.) http://www.slac.stanford.edu/~asarti/recoil/update/MNH69.eps http://www.slac.stanford.edu/~asarti/recoil/update/Meandist_9.eps http://www.slac.stanford.edu/~asarti/recoil/update/Sigdist_9.eps & for Vcb (fit -80MeV- ; mean distribu.; sig distr.) http://www.slac.stanford.edu/~asarti/recoil/update/vcb/MNH69.eps http://www.slac.stanford.edu/~asarti/recoil/update/vcb/Meandist_9.eps http://www.slac.stanford.edu/~asarti/recoil/update/vcb/Sigdist_9.eps As you can see the plots are quite different from the last ones that I've presented. This is expecially true for the last points of those plots (10 -> 14). (Th first 10 points are still energy cuts, but going from 20 Mev to 110 MeV: The 80 meV cut is the 7th point placed in bin == 6 I've done this to remove the firts dummy cut E = 10) This is because we have replaced the 12th point (cut in forward and bkw regions) with a new cut: 12th point = Cut on energy (E>80MeV) && Cut on the number of neutral reconstructed (n <= 2). ( See vub: http://www.slac.stanford.edu/~asarti/recoil/update/MNH129.eps & vcb: http://www.slac.stanford.edu/~asarti/recoil/update/vcb/MNH129.eps ) To understand the reason of this new cut you can see the follwing plots showing the resolution on Mx (no kinematic fitting and no bkg subtraction) for: a) all candidates (white) && only chg particles (red) http://www.slac.stanford.edu/~asarti/recoil/update/Mxreso_cont_ch.eps b) all candidates (white) && only neu particles (red) http://www.slac.stanford.edu/~asarti/recoil/update/Mxreso_cont_neu.eps c) all candidates (white) && only events with 2 neutrals (red) http://www.slac.stanford.edu/~asarti/recoil/update/Mxreso_compch2neu.eps d) all candidates divided in variuos contribution: http://www.slac.stanford.edu/~asarti/recoil/update/Mxreso_cont.eps red = all events with <= 3 neutrals reco green = all events with <= 2 neutrals reco blue = all events with <= 1 neutrals reco yellow = all events with == 0 neutrals reco (only chg part) If you now see the optimization plots: r : http://www.slac.stanford.edu/~asarti/recoil/update/MXEvents9.eps Mx : http://www.slac.stanford.edu/~asarti/recoil/update/MEvents9.eps Seems that this cut is powerful. Of course the problem is that we are loosing a part of Vub events. (Compare: E == 80Mev cut http://www.slac.stanford.edu/~asarti/recoil/update/MNH69.eps E == 80Mev cut + Num of gamm <= 2 http://www.slac.stanford.edu/~asarti/recoil/update/MNH129.eps ) If you mind why the cut on the gammas mother identity does not reflect now the gain that we see with a simple number of gammas cut (<=2) you can see: http://www.slac.stanford.edu/~asarti/recoil/update/Mxreso_comppiz.eps that shows the contribution to the residual Mx distribution from events with only gammas from pi0s. The Fw and Bw regions are no longer considered because of cutting events at low energy leads only to a worse statistics and does not gives a better sigma or ratio (You can see the last point -bin = 14- in each of the above plots...) The possibility of applying this "number of gamma" cut has to be discussed and, of course, needs further study mainly because of the gain in the not kinematic constrained Mx residual distribution (saving a very good fraction of the core events). Any comment or question is welcomed. Cheers, Alessio ______________________________________________________ Alessio Sarti Universita' & I.N.F.N. Ferrara tel +39-0532-781928 Ferrara "Quod non fecerunt barbari, fecerunt Berlusconi" "Che il bianco sia bianco, e che il nero sia nero che uno e uno fanno due e che la scienza dice il vero.... DIPENDE !"