Hi Daniele,

> > First, how can you have nle==1 && nchg==0? The lepton is included in nchg,
> > so if you have a lepton, nchg is at least 1, correct?
>
> in our old symbols nchg = 0 means 0 tracks in the X system. Then my nchg =
> 0 is your nchg = 1. Sorry for the confusion. I will use your convention in
> future.

I did not know of the old convention, sorry about that.

> > Second, we do not see what this other category for the unfolding should
> > look like. It would need to have a consistent definition between reco and
> > truth level.
> > We could make a category that has nchg==1&&nneu==0, but it would be (at
> > least nearly) empty on the reco side since these events do not pass the
> > cuts. It would be empty on the truth side because there are no such
> > signal events at truth level, correct?
>
> You could have some categories at the truth level and some other
> categories at the reconstructed level. For instance, suppose you have
> pilnu at MC level. This event will have nchg = 2 and nneu = 0. Suppose you
> loose the charged track, then this event will be in the category nchg = 1
> and nneu = 0, that at the moment you are neglecting. In principle this
> event can give some information about the original MC mode because the
> probability to have nchg = 1 and nneu = 0 at the reconstructed level is
> higher for pilnu than for a1lnu, for example.

Ok. We (Heiko and myself) talked about this and yes, in principle we could
have different definitions of the categories at truth and reco level. We
see that we could have a better definition of the categories at truth
level when we take physics information from the decays into account. But
given that the statistical uncertainties on our weights for the multiplicity
category reweighting are quite large (see Table 2 in the BAD) we would only
expect a minor effect when changing the definition. So it might be interesting
to implement this in a future analysis with more statistics.

> If it is not clear we can chat on the phone about this.
>
> > In the MC I looked at I did not see any reco'd events passing the cuts so
> > how could one reduce the statistical error?
>
> are you saying that after all analysis cuts there is no event in the
> category nchg = 1 and nneu = 0? What if you remove Qtot = 0 cut?

I only applied the pcms>1 cut, none of the others. This cut already
removed all those events in this sample I looked at. I just had a look at
the qtot distribution and I see events with qtot=0,+-1,+-2 when demanding
nneu==0&&nchg==1.

Kerstin