Event Selection using Run2                                                                        Kenji Hamano

Last modified : Jun 20, 2007                                              Back to Home Back to privious page

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Event Selection

R16b skims Run2 was used.
On Peak data luminosity: 59.4 fb-1

All MC numbers are luminosity normalised to OnPeak data

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0. BToDlnu skim

Delta_S / S = 0.0195171 (D0), 0.0268934 (D+)
Number of candidates & Delta_S / S

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1. Tihghter Kaon Selection

Use KMicroNotPion selector

Delta_S / S = 0.0115441 (D0), 0.0268934 (D+)
Number of candidates & Delta_S / S

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3. D and B vertexing

Tihghter Kaon Selection is applied.
D and B vertexing using TreeFitter

Number of candidates & Delta_S / S
B=Non,D=Non
B=Non,D=0.0001
B=Non,D=0.001
B=Non,D=0.01
B=Non,D=0.1
B=0.0001,D=Non
B=0.0001,D=0.0001
B=0.0001,D=0.001
B=0.0001,D=0.01
B=0.0001,D=0.1
B=0.001,D=Non
B=0.001,D=0.0001
B=0.001,D=0.001
B=0.001,D=0.01
B=0.001,D=0.1
B=0.01,D=Non
B=0.01,D=0.0001
B=0.01,D=0.001
B=0.01,D=0.01
B=0.01,D=0.1
B=0.1,D=Non
B=0.1,D=0.0001
B=0.1,D=0.001
B=0.1,D=0.01
B=0.1,D=0.1

Err (D0 only)	no cut	D prob > 0.0001	0.001	0.01	0.1
no cut	0.01154	0.01055	0.01043	0.01027	0.01031
B prob > 0.0001	0.00974	0.00973	0.00968	0.00959	0.00969
0.001	0.00955	0.00955	0.00953	0.00947	0.00959
0.01	0.00929	0.00929	0.00929	0.00928	0.00943
0.1	0.00911	0.00911	0.00911	0.00911	0.00925

Err (D+ only)	no cut	D prob > 0.0001	0.001	0.01	0.1
no cut	0.02689	0.02275	0.02252	0.02223	0.02226
B prob > 0.0001	0.02168	0.02165	0.02152	0.02131	0.02139
0.001	0.02131	0.02131	0.02127	0.02112	0.02124
0.01	0.02079	0.02079	0.02079	0.02077	0.02099
0.1	0.02038	0.02038	0.02038	0.02038	0.02056

Best uncertainty is given by D prob > 0.01 and B prob > 0.1
But, since no big difference on uncertainties, we prefer looser cut.
Thus, the best cut is D prob > 0.001 and B prob > 0.01

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4. Thrust cut

Tihghter Kaon Selection is applied.
D prob > 0.001 and B prob > 0.01 applied

Using thrust of Dl and non-Dl, apply cuts on |cosTheta_{Dl-nonDl}|
Plot (D0)
Plot (D+)

Number of candidates & Delta_S / S
No cut
0.96
0.92
0.88
0.84
0.80

(D0)	Err
no cut	0.00929
|cosTheta| < 0.96	0.00823
0.92	0.00764
0.88	0.00725
0.84	0.00697
0.80	0.00680

(D+)	Err
no cut	0.02079
|cosTheta| < 0.96	0.01889
0.92	0.01770
0.88	0.01690
0.84	0.01635
0.80	0.01600

Best uncertainty is given by |cosTheta_{Dl-nonDl}| < 0.80
But, since no big difference on uncertainties after 0.92, we prefer looser cut.
Thus, the best cut is |cosTheta_{Dl-nonDl}| < 0.92

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Summary of cuts

Err	D0	D+
BToDlnu skim	0.01952	0.0269
KMicroNotPion	0.01154	0.0269
Vtx B=0.01, D=0.001	0.00929	0.0208
|cosTheta| < 0.92	0.00764 (39 %)	0.0177 (66 %)

Nunber of signal candidates	D0	D+
BToDlnu skim	300194	177725
KMicroNotPion	292993 (97.6 %)	177725 (100 %)
Vtx B=0.01, D=0.001	276669 (92.2 %)	161267 (90.7 %)
|cosTheta| < 0.92	250420 (83.5 %)	146269 (82.3 %)

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Cut flow table

Yeild = sideband subtracted number of candidates.
0BToDlnuSkim
1TightKCuts
3VtxCuts
4ThrustCuts

D0	OnPeak - Off Peak yeild	efficiency	cumultive efficiency	BBbar MC yeild	efficiency	cumultive efficiency
BToDlnu skim	381377	n/a	n/a	411274	n/a	n/a
Tight K	379722	0.9957	0.9957	405898	0.9869	0.9869
Vertexing	340517	0.8968	0.8929	372283	0.9172	0.9052
Thrust cut	302788	0.8892	0.7939	332782	0.8939	0.8091
D+	OnPeak - Off Peak yeild	efficiency	cumultive efficiency	BBbar MC yeild	efficiency	cumultive efficiency
BToDlnu skim	232505	n/a	n/a	283572	n/a	n/a
Tight K	232509	1.0000	1.0000	283572	1.0000	1.0000
Vertexing	199994	0.8602	0.8602	246511	0.8693	0.8693
Thrust cut	178595	0.8930	0.7681	217339	0.8817	0.7664

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