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Analysis of D0 Pair Crossfeed and Invariant Mass Using Open and Production Cuts

This study investigates the crossfeed of D0 pairs in various momentum ranges, highlighting the effects of specific cutting criteria on the invariant mass distributions. Key findings demonstrate that as the transverse momentum (pT) of the pair increases, crossfeed decreases, reaching a plateau of approximately 35%. Further analysis of invariant mass distributions reveals significant shifts based on used cuts, with notable differences in mass width and mean values among true D0 pairs and crossfeed. Statistical assessments of error bars indicate increased uncertainties with lower statistics in third production samples.

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Analysis of D0 Pair Crossfeed and Invariant Mass Using Open and Production Cuts

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  1. Crossfeed studies • Run the single D0 sample with : • Open cuts (plots sent yesterday) • First production cuts • Third production cuts • Plots of crossfeed vs. pT pair (Kπ) • Crossfeed defined as : # pairs (Kπ) / # ALL pairs • Plots of mass width and mean vs. pT pair (Kπ)

  2. Open cuts

  3. First production

  4. Third production

  5. comments • The 3 samples show the same behaviors : • Crossfeed decreases with pT of pair • Plateau ~ 35% • Crossfeed is lower when taking only mass entries in [1.7;2.0], means more crossfeed have wrong mass value

  6. Inv mass • I looked at the invariant mass of true pair and crossfeed (wrong sign), in particular the mean and width since I saw yesterday a broader width when plotting the inv. Mass of crossfeed

  7. Open cuts • error bars are the fit parameters errors • The error bar for the last bin should be asymmetric in pT[2,20] • Plot on the bottom left is an example for a given pT bin of the fits

  8. First production

  9. Third production

  10. comments • For 3 samples : • Mean of fit : • Constant for true D0 pair • Slightly shifted for crossfeed and increases with pT of pair • Width of fit : • around  ~ 15 MeV for true D0 and slight increase with pT (expected) • Around twice the true D0 pair and large increase with pT • Inv mass histo : we see (left bottom plot) the effect of cuts in the # of entries : • The maximum of the inv. Mass distribution decreases from 1000 (open cuts) to 150 and 250 (first and third production)

  11. Pico cuts • Run the third production with the cuts used to make the pico files • Cuts are : • |D0|<1.85 • Probability>.1 • |dcaXYtoPV|<.1cm • |yD0|<.5 • |cosine(theta*)|<.6 • Silicon hits>2 • The cuts used in the plots here are only : • MuKpi (see last slides) • Pico cuts (see above) • For the invariant mass making, I don’t use other cuts

  12. crossfeed

  13. Inv. Mass vs pT D0

  14. comments • With the cuts used to make the pico files, the crossfeed is flattened • But error bars have increased because of the low statistic

  15. Open cuts • static const Double_t pTCut = 0.1; // transverse momentum cut • static const Double_t PCut = 0.1; // momentum cut • static const Double_t sumPCut = .5 ; // sum of momentum(kaon)+momentum(pion) • static const Double_t mKpiMin = 0.; // min mass of (Kpi) association • static const Double_t mKpiMax = 5; // max mass of (Kpi) association • static const Double_t DcaCut = 1; // single track DCA to PV • static const Int_t TpcCut = 10; // TPC hits fitted • static const Float_t TpcRatioCut = 0.51; // TPC hits fitted / TPC hits Poss • static const Double_t TrackLengthCut = 40; // min value for dEdxTrackLength • static const Int_t SiCut = 0; // (SVT+SSD) hits fitted • static const Int_t SvtCut = 3; // (SVT) hits fitted • static const Int_t SsdCut = 1; // (SSD) hits fitted • static const Float_t RadiusCutSvt1 = 9.0; • static const Float_t RadiusCutSvt2 = 13.0; • static const Float_t SigmaPionCut = 4.; // nsigma for pion • static const Float_t SigmaKaonCut = 4.; // nsigma for kaon • static const Float_t SigmaProtonCut = 4.; // nsigma for Proton • static const Double_t EtaCut = 2; // track pseudorapidity • static const Double_t zcut = 30; // zvertex cut • static const Double_t cosThetaCut = 1; • static const Double_t rapCandCut = 2.0; • static const Double_t slengthCut = 10; // max value of decaylength calculated by TCFIT • static const Double_t dslengthCut = 10; // max value of the error associated to the decaylength from TCFIT • static const Double_t ProbCut = 0.005; // min value of probability of FIT • static const Int_t writeHisto = 1; // flag to write histos

  16. First production : cuts • static const Double_t pTCut = 0.5; // transverse momentum cut • static const Double_t PCut = 0.5; // momentum cut • static const Double_t mKpiMin = 1.2; // min mass of (Kpi) association • static const Double_t mKpiMax = 2.2; // max mass of (Kpi) association • static const Double_t DcaCut = .1; // single track DCA to PV • static const Int_t TpcCut = 20; // TPC hits fitted • static const Double_t TrackLengthCut = 40; // min value for dEdxTrackLength • static const Int_t SiCut = 3; // (SVT+SSD) hits fitted • static const Int_t SvtCut = 3; // (SVT) hits fitted • static const Int_t SsdCut = 1; // (SSD) hits fitted • static const Float_t SigmaPionCut = 2.; // nsigma for pion • static const Float_t SigmaKaonCut = 2.; // nsigma for kaon • static const Float_t SigmaProtonCut = 2.; // nsigma for Proton • static const Double_t EtaCut = 1; // track pseudorapidity • static const Double_t zcut = 10; // zvertex cut • static const Double_t PrimZResCut = 0.020; // zvertex resolution cut • static const Double_t cosThetaCut = 0.6; • static const Double_t rapCandCut = 2.0; • static const Double_t slengthCut = 10; // max value of decaylength calculated by TCFIT • static const Double_t dslengthCut = 10; // max value of the error associated to the decaylength from TCFIT • static const Double_t ProbCut = 0.005; // min value of probability of FIT • static const Int_t writeHisto = 1; // flag to write histos

  17. Third production : cuts • static const Double_t pTCut = 0.5; // transverse momentum cut (not used) • static const Double_t PCut = 2.0; // momentum cut (not used) • static const Double_t sumPCut = 1.5 ; // sum of momentum(kaon)+momentum(pion) • static const Double_t mKpiMin = 1.2; // min mass of (Kpi) association • static const Double_t mKpiMax = 2.2; // max mass of (Kpi) association • static const Double_t DcaCut = 0.2; // single track DCA to PV • static const Int_t TpcCut = 25; // TPC hits fitted • static const Float_t TpcRatioCut = 0.51; // TPC hits fitted / TPC hits Poss • static const Double_t TrackLengthCut = 40; // min value for dEdxTrackLength • static const Int_t SiCut = 2; // (SVT+SSD) hits fitted • static const Int_t SvtCut = 3; // (SVT) hits fitted • static const Int_t SsdCut = 1; // (SSD) hits fitted • static const Float_t RadiusCutSvt1 = 9.0; • static const Float_t RadiusCutSvt2 = 13.0; • static const Float_t SigmaPionCut = 2.5; // nsigma for pion • static const Float_t SigmaKaonCut = 2.5; // nsigma for kaon • static const Float_t SigmaProtonCut = 3.; // nsigma for Proton • static const Double_t EtaCut = 1.2; // track pseudorapidity • static const Double_t zcut = 10; // zvertex cut • static const Double_t PrimZResCut = 0.020; // zvertex resolution cut • static const Double_t cosThetaCut = 0.8; • static const Double_t rapCandCut = 1.0; • static const Double_t slengthCut =.2; // max value of decaylength calculated by TCFIT • static const Double_t dslengthCut =.1; // max value of the error associated to the decaylength from TCFIT • static const Double_t ProbCut =.05; // min value of probability of FIT • static const Int_t writeHisto = 1; // flag to write histos

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