Investigation of Cuts

1. Investigation of Cuts Jaiby Joseph 04/27/2011

2. I looked at the signal, Sqrt(Bkg) and S/√B distributions(1D,2D) of some of the cut variables in the following slides. • Sample used is power law single D0 dataset for signal behavior and hijing for background. • I also plot the Inv Mass distributions for the highest significance cut values

3. slength(fixed D0dcaPV) √B S S/√B Possible cut value

4. D0dcaPV(fixed slength) S √B S/√B

5. Dca between Tracks (fixed slength) S √B S/√B

6. EtaD0 S √B S/√B

7. slength/dslength(fixed D0dcaPV) √B S S/√B

8. slength Vs slength/dslength(D0dcaPV>0, updated) √B S S/√B (2.75, 0.04) (1.35, 0.03) (2.75,0.025) (1.9,0.015) (0.2,0.005)

9. D0dcaPV Vs slength/dslength(slength>0, updated) √B S S/√B Possible graphical selection (0.2,0) (1.8,0.015) (2.6,0.025) (2.2,0.03) (1.3,0.02) (0.8,0.02) (0.2,0)

10. TrkDcaKpi Vs slength/dslength(fixed slength) S B

11. slength significance of daughters (Kaon) Possible graphical selection (0.7,6) (0.7,0) (3.2,0) (3.2,2) (0.7,6)

12. slength significance of daughters (Pion) Possible graphical selection (0.7,6) (0.7,0) (1.5,1) (3.2,0) (0.7,6)

13. DcaKpi Vs PD0 S √B S/√B

14. slength Vs pD0 D0dcaPV>0

15. opening phi angle Vs PD0

16. opening phi angle Vs PD0 √B S S/√B

17. dE/dx Vs p 3rdProdCutsSignal - Left, Bkg- Right ChargeK<0 ChargePi>0 ChargeK<0 ChargePi>0 Inv Mass Inv Mass

18. dE/dx Vs p (nSigma cut modified) New nSigma cut ChargeK<0 ChargePi>0 ChargeK<0 ChargePi>0 Signal reduces to 23.4% Background reduces to 14%

19. Invariant Mass Plots

20. Inv Mass Plots from Embedding (after pico cuts)

21. cut on D0dcaPV

22. Changing the dE/dxcut(as in slide12) After new dE/dx cut Before dE/dx modification

23. Real Data Signal Bkg Subtracted D0Tree->Draw("MassD0>>hD0dL12D0dca6dLSig1D0Eta3","ChargeKaon<0&&ChargePion>0&&slength>0.005&&slength<0.04&&(slength*SinPointing)>0&&(slength*SinPointing)<0.02&&slength/dslength>0.2&&abs(EtaD0)<1.0","e"); D0Tree->Draw("MassD0>>hD0bardL12D0dca6dLSig1D0Eta3","ChargeKaon>0&&ChargePion<0&&slength>0.005&&slength<0.04&&(slength*SinPointing)>0&&(slength*SinPointing)<0.02&&slength/dslength>0.2&&abs(EtaD0)<1.0","e");

24. real data with modified dE/dx Events ~ 26M Modified dE/dx: Kaon: if P < 1.2GeV/c, 0<nSigma<2 else, -2<nSigma<0 Pion: if P < 1.2 GeV/c, -2<nSigma<0 else, 0<nSigma<2 D0Tree->Draw("MassD0>>hD0dL12D0dca6dLSig1D0Eta3","ChargeKaon<0&&ChargePion>0&&slength>0.005&&slength<0.04&&(slength*SinPointing)>0&&(slength*SinPointing)<0.03&&slength/dslength>0.2","e");

25. Use Graphical cut +modified dE/dx cut Since the signal distribution shows clear difference in the slength Vs slength/dslength plot (sllide 8). Next would be to try a graphical selection cut in the highest significance region of the plot. Highest significance region from pureD0 sample selection from real data

26. real data (till day160) with modified dE/dx graphical selection+0<D0dcaPV<300, ChargeKaon<0, ChargePion>0 Signal Bkg

27. Graphical cut on slength and D0dcaPV Vs slength/dslength graphical selection on slength&D0dcaPV, ChargeKaon<0, ChargePion>0

28. Graphical Cut on slength,D0dcaPV and slength Significance of daughters Signal Bkg Cuts as shown on: slide8 slide9 slide 11&12

29. Low pT D0s D0Tree->Draw("MassD0>>hSSPhi1Mom5","(abs(PhiKaon-PhiPion)*57.28)>140&&(abs(PhiKaon-PhiPion)*57.28)<200&&PtPion>0.5&&PtPion<1.4&&PtKaon>0.5&&PtKaon<1.4&&ChargeKaon*ChargePion>0","e");

30. Back-Up

31. slength Vs slength/dslength(for |D0dcaPV|<0.02) √B S S/√B

32. D0dcaPV Vs slength/dslength(-0.015<slength<0.04)

33. |nSigma|<1 ChargeK<0 ChargePi>0 ChargeK<0 ChargePi>0 Inv Mass Inv Mass

34. DcaXY/SigmaDcaXY(Pion) S √B

35. DcaXY/SigmaDcaXY(Kaon) √B

36. DcaXY/SigmaDcaXY(Pion) √B

37. dE/dx Vs p (Signal-3rdProdCuts) Single D0s Using 3rd Prod Macro ChargeK<0 ChargePi>0 ChargeK<0 ChargePi>0

38. dE/dx Vs p (Background-3rdProdCuts) ChargeK<0 ChargePi>0 ChargeK<0 ChargePi>0