All cuts:

===============================Table for ee

sample	Yield
DY	1.41 ± 0.02
qcd15	0.00 ± 0.00
Total MC	1.41 ± 0.02
data	7.00

===============================Table for mm

sample	Yield
DY	2.79 ± 0.02
qcd15	1.55 ± 1.09
Total MC	4.33 ± 1.09
data	7.00

===============================Table for em

sample	Yield
DY	0.04 ± 0.003
qcd15	1.55 ± 1.09
Total MC	1.59 ± 1.09
data	2.00

===============================Table for all

sample	Yield
DY	4.24 ± 0.03
qcd15	3.09 ± 1.55
Total MC	7.33 ± 1.55
data	16.00

With no Iso:

===============================Table for ee

sample	Yield
DY	1.52 ± 0.02
qcd15	20.88 ± 4.02
Total MC	22.41 ± 4.02
data	21.00

===============================Table for mm

sample	Yield
DY	2.96 ± 0.03
qcd15	17.02 ± 3.63
Total MC	19.98 ± 3.63
data	21.00

===============================Table for em

sample	Yield
DY	0.06 ± 0.003
qcd15	22.43 ± 4.17
Total MC	22.49 ± 4.17
data	17.00

===============================Table for all

sample	Yield
DY	4.54 ± 0.03
qcd15	60.33 ± 6.83
Total MC	64.87 ± 6.83
data	59.00

===============================Table for ee

sample	Yield
DY	1.41 ± 0.02
qcd15	0.00 ± 0.00
Total MC	1.41 ± 0.02
data	7.00

===============================Table for mm

sample	Yield
DY	2.79 ± 0.02
qcd15	1.55 ± 1.09
Total MC	4.33 ± 1.09
data	7.00

===============================Table for em

sample	Yield
DY	0.04 ± 0.003
qcd15	1.55 ± 1.09
Total MC	1.59 ± 1.09
data	2.00

===============================Table for all

sample	Yield
DY	4.24 ± 0.03
qcd15	3.09 ± 1.55
Total MC	7.33 ± 1.55
data	16.00

Looks like the Isolation is doing this....

Try with els_tkIso instead of els_tkJuraIso. Id and iso cuts are applied:

===============================Table for ee

sample	Yield
DY	1.41 ± 0.02
qcd15	0.00 ± 0.00
Total MC	1.41 ± 0.02
data	7.00

===============================Table for mm

sample	Yield
DY	2.79 ± 0.02
qcd15	1.55 ± 1.09
Total MC	4.33 ± 1.09
data	7.00

===============================Table for em

sample	Yield
DY	0.04 ± 0.003
qcd15	1.55 ± 1.09
Total MC	1.59 ± 1.09
data	2.00

===============================Table for all

sample	Yield
DY	4.24 ± 0.03
qcd15	3.09 ± 1.55
Total MC	7.34 ± 1.55
data	16.00

Looks like the diff is ID. The only cuts that are applied below are :

if (!(els_type()[lepIdx] & (1<<ISECALDRIVEN))) return false; if (fabs(els_p4()[lepIdx].eta()) > 2.5) return false; if (electronId_noMuon(lepIdx)) return false; if (electronId_cand01(lepIdx)) return false; if (electronImpactTTbar(lepIdx)) return false; if (isFromConversionPartnerTrack(lepIdx)) return false;

In the Summer 09 sample, just in the ee channel, we get:

===============================Table for ee

sample	Yield
qcd15	32.47 ± 4.69
Total MC	32.47 ± 4.69

In the Spring 10 sample: ===============================Table for

sample	Yield
qcd15	20.88 ± 4.02
Total MC	20.88 ± 4.02