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Hadron ID and Event-by-event Fluctuations of the Kaon to Pion Ratio. D. Kresan, GSI, Darmstadt. 13 -th CBM Collaboration Meeting 9 – 13 March 2009 GSI, Darmstadt. Simulation tools. CBMROOT trunc version (revision 4448) STS 8 Strips TRD 3x4 Setup
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Hadron ID and Event-by-event Fluctuations of the Kaon to Pion Ratio D. Kresan, GSI, Darmstadt 13-th CBM Collaboration Meeting 9 – 13 March 2009 GSI, Darmstadt
Simulation tools • CBMROOT trunc version (revision 4448) • STS • 8 Strips • TRD • 3x4 Setup • Hit Producer: Angular dependent strip-like smearing • TOF • Segmented geometry • Hit Producer: double hits • 80ps time resolution D.Kresan CBM Collaboration Meeting, GSI, Darmstadt
Track cuts • Select only primaries • Identification of tracks is done using momentum-dependent window around the true squared mass D.Kresan CBM Collaboration Meeting, GSI, Darmstadt
STS Reconstruction D.Kresan CBM Collaboration Meeting, GSI, Darmstadt
TRD Reconstruction D.Kresan CBM Collaboration Meeting, GSI, Darmstadt
Global Tracking D.Kresan CBM Collaboration Meeting, GSI, Darmstadt
Squared Mass Spectra D.Kresan CBM Collaboration Meeting, GSI, Darmstadt
Correctly Reconstructed Tracks D.Kresan CBM Collaboration Meeting, GSI, Darmstadt
Squared Mass Resolution D.Kresan CBM Collaboration Meeting, GSI, Darmstadt
Kaon pt at midrapidity purity 90% D.Kresan CBM Collaboration Meeting, GSI, Darmstadt
pt – y distributions purity 90 % D.Kresan CBM Collaboration Meeting, GSI, Darmstadt
Dynamical Fluctuations Measure the particle yields ratio in an event : K/ = RMS / MEAN Relative width of distribution : data2 = fin2 + exp2 + dyn2 background mixed Event mixing: no two tracks coming from one real event dyn2 = data2 mixed2 D.Kresan CBM Collaboration Meeting, GSI, Darmstadt
Results from UrQMD 4 RECO+PID No large acceptance bias D.Kresan CBM Collaboration Meeting, GSI, Darmstadt
Purity Study: K/ D.Kresan CBM Collaboration Meeting, GSI, Darmstadt
Purity Study: p/ D.Kresan CBM Collaboration Meeting, GSI, Darmstadt
4 D.Kresan CBM Collaboration Meeting, GSI, Darmstadt
acc D.Kresan CBM Collaboration Meeting, GSI, Darmstadt
RECO purity 50% D.Kresan CBM Collaboration Meeting, GSI, Darmstadt
Conclusion • Exponential tails in mass spectrum are due to mismatches and TOF double hits • Investigation of the effect of kaon purity was done for K/ and p/ ratios • Increase of K/ fluctuations due to limited momentum range • Agreement between "real" and MC (with p cut) results • no bias due to acceptance, reconstruction and identification D.Kresan CBM Collaboration Meeting, GSI, Darmstadt