Event Selection using Run1234                                                                        Kenji Hamano

Last modified : Dec 12, 2007                                              Back to Home Back to privious page

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Event Selection

R16b skims Run1-4 was used.
All MC numbers are luminosity normalised to OnPeak data

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0. BToDlnu skim

Delta_S / S = 0.0115212 (D0), 0.0153828 (D+)
Number of candidates & Delta_S / S
D mass plot

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1. Tihghter Kaon Selection

Use KMicroNotPion selector

Delta_S / S = 0.00656846 (D0), 0.0153831 (D+)
Number of candidates & Delta_S / S
D mass plot

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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
    D mass plot
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)	D prob >
B prob >	no cut	0.0001	0.001	0.01	0.1
no cut	0.00656846	0.00595032	0.005886	0.005807	0.00589463
0.0001	0.00549184	0.00548224	0.00545542	0.00541834	0.00553709
0.001	0.0053846	0.00538357	0.00537378	0.00534861	0.00547657
0.01	0.00524898	0.00524829	0.00524816	0.00524554	0.00538858
0.1	0.00520427	0.00520395	0.00520386	0.00520368	0.00530704

Err (D+ only)	D prob >
B prob >	no cut	0.0001	0.001	0.01	0.1
no cut	0.0153831	0.0128289	0.012697	0.012555	0.0127351
0.0001	0.0122143	0.0121979	0.0121232	0.0120253	0.0122308
0.001	0.0120045	0.0120040	0.0119866	0.0119202	0.0121446
0.01	0.011742	0.0117418	0.0117417	0.0117389	0.012004
0.1	0.011672	0.0116718	0.0116718	0.0116716	0.0118123

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
    D mass plot
    D mass plot (Electron only)
    D mass plot (Muon only)
0.88
0.84
0.80

(D0)	Err
no cut	0.00524816
|cosTheta| < 0.96	0.00462526
0.92	0.00428304
0.88	0.00405069
0.84	0.00388861
0.80	0.00378443

(D+)	Err
no cut	0.0117417
|cosTheta| < 0.96	0.0106368
0.92	0.00991743
0.88	0.00943539
0.84	0.00910735
0.80	0.00890127

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
2DonlyVtxCuts
3VtxCuts
4ThrustCuts

D0	OnPeak - Off Peak yeild	efficiency	cumultive efficiency	BBbar MC yeild	efficiency	cumultive efficiency
BToDlnu skim	1.33881e+06	n/a	n/a	1.46792e+06	n/a	n/a
Tight K	1.34097e+06	1.002	1.002	1.4449e+06	0.9871	0.9871
Vertexing	1.1961e+06	0.8920	0.8934	1.32037e+06	0.9138	0.8995
Thrust cut	1.06508e+06	0.8905	0.7955	1.17891e+06	0.8928	0.8031
D+	OnPeak - Off Peak yeild	efficiency	cumultive efficiency	BBbar MC yeild	efficiency	cumultive efficiency
BToDlnu skim	825616	n/a	n/a	1.00608e+06	n/a	n/a
Tight K	825625	1.0000	1.0000	1.00606e+06	1.0000	1.0000
Vertexing	700745	0.8487	0.8487	870188	0.8494	0.8494
Thrust cut	621453	0.8868	0.7527	766995	0.8814	0.7624

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