Hir Henning,
> I have a question concerning the change of Breco purity when moving from
> SP4/rel.10 (most of the run1-2 analyses) to SP6/rel.14 (run1-4).
>
> Do you see a reduction in purity with the newer reconstruction release in
> both data and MC?
> And can you possibly quantify it?
the purity with no DE cut should be improved since the skim rate went from
4% to 1.5% on data. Once you apply the mode dependent deltaE cut you
should get a similar purity compared to rel 10 (probably slightly worse).
Which machinery are you using to produce ntuples and to select the best B?
> Similarily for the yield, I guess this is higher per fb-1 for the new
> release but does someone have some numbers?
there should be an increase of around 15-20%.
> I expect you only have these numbers for events with an identified lepton
> and not for all Breco candidates, but this would already help.
for a per mode comparison (no cut) you can compare the tables in
http://www.slac.stanford.edu/~daniele/breco/temp/sxModes-{2,3,4,5}.html
for run1-4 rel14
with
http://www.slac.stanford.edu/BFROOT/www/Physics/Analysis/AWG/InclusiveSL/islrecoil/data0909_80fb-1/sxModes-{2,3,4,5}.html
for 80 fb-1 rel10
> For the Breco b->sg analysis we see a higher (BB) background i.e. reduced
> purity and would like to better understand this.
the lower purity can be due to just few new modes that were not present in
rel 10 (because of the new tables). If they bother a lot you can identify
them and cut them out.
Daniele
