 |
 |
Riccardo Faccini wrote: > Hi Guglielmo, > I am quite surprised that the events with a Kl have such a soft spectrum. > The peakshould be around 2 GeVwhile it is below 1.5. Can you please check > the events with a K+ and see if you are getting a harder spectrum? Why should it be ? Don't you expect to loose most of the Kl energy ? > > > As far as the fact tht the Ks removed calculation is too soft, it would > indicate that you need to estimte the average energy of the Kl and add it > back to the event > ciao > ric > > On Wed, 13 Feb 2002, Guglielmo De Nardo wrote: > > > Hi, > > > > In order to estimate the low Mx shape of Vcb background with KL, I > > produced the following plots: > > http://www.slac.stanford.edu/~denardo/mxplots/klmasslepton.ps > > http://www.slac.stanford.edu/~denardo/mxplots/kstruemasslep.ps > > > > They both are from true Vcb events. > > The first plot is the MX distribution for events with at least a true KL. > > The second plot is again the MX distribution after subtraction of a > > reconstructed Ks. If more than one Ks is reco'ed, the one with the > > smallest delta m is chosen. > > > > For both the distribution no selection cut is applied, apart requiring a > > lepton in the fiducial acceptance. > > > > I naively expected to find similar distributions. Instead, the Ks looks > > too much distorted towards small values of MX. > > > > Tomorrow I will change the code to add all the selected Ks (one by one) to > > the distribution, but I expect that this will only add few more entries > > but it will not change the shape. > > Someone has any idea on why the MX ks-subtracted distribution should look > > so different from KL events Mx one? (I can't exclude a bug in my code). > > > > Tomorrow I will investigate further. > > > > Guglielmo > > > > > > > > > >