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Hi, I put some plots in http://www.slac.stanford.edu/~denardo/vub/mxstudymar152002 The plots in ks.ps show the mass of the ks we use to tag a Vcb event. The first plot show all the "best" ks, while the second and the third the mass in events with and without a true ks respectively. Best ks is the one with the smallest residual w.r.t. nominal mass. Since the window is very loose I used a narrower one in selecting ks to remove from the event to mimic the KL component in vub enriched sample. In the file named mx.ps the MX distribution are plotted for the following cases: 1. comparison between true KL in vub enriched sample (blue) and events with the ks removed (from vcb enriched). 2. the same for True K+ not reconstructed in vub enriched sample and events with K+ removed from vcb enriched. 3. the same for mis-id kaon in vub enriched sample and reconstructed kaon with the mass forced to that of a pion in vcb enriched sample. The comparison is not very satisfactory. I have to investigate further... Then in klresall.ps are shown 1. the difference between the polar angles of the true KL and a cluster in the EMC with energy greater than 80 MeV. 2. the same for phi. This is see if it is possible to make a MC associator for the KL just using the geometrical matching and to tune it. The plot in klres.ps show the same thing when there is at least a cluster not associated to any particle (like I thinked it was the case of KLs). But I found the this is not true, because the number of events is too small. Finally I have the breakdown of ks component in vub enriched sample: ks -> pi+ pi- = 34 % Ks -> pi0 pi0 = 66 % Guglielmo