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Test of TCFIT in reco. code (update ). Test on pure D 0 ( ) Test on embedding : D 0 mixed with HIJING events Test with Real data. Estimation of D 0 cross-section.
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Test of TCFIT in reco. code(update ) Test on pure D0 () Test on embedding : D0 mixed with HIJING events Test with Real data
Estimation of D0 cross-section • Rerun over files with loosening a bit some cuts (#tracks<700, |nK|<3, |nπ|<3, remove the cut on slength (linear) and put a cut on prob(TCFIT)>0.01 • Make inv. Mass plots for different pT bins • Estimate the number of counts (=entries per bins in the interesting range)(with BRTW macro) after background substraction • Make d2N/pTdpTdy plot (normalized by 1/Nevents*2π ), rapidity of D0 |y|<0.5
comments • For both cases (no cut and cut on the number of tracks), a clear peak appears for high pT D0 • I have checked that the pT range of the hijing background and the D0 are the same : No possibility that for a given pT, there is only D0 • For #tracks<200, there is quasi no background is flat for pT>3 GeV/C • since a clear peak is needed for the estimation of counts, I use the #tracks cut
Example : 2 <pT≤3 Raw histogram • After using the BRTW.C macro, the bottom histogram (blue curve) is after the background substraction (note the level ~ at 0) • I choose [1.82;1.94] for the mass range : • 114±38 counts in this range (the error is the sum of the bin error in the mass range)
Number of events After |zvertex| cut After #tracks cut The number of events used is then 5110
This bin gives a very bad inv. Mass So the value and error are not very good spectra • The log plot does not look very nice • I would prefer to make the inv. Mass w/o the cut on #tracks
details Took macros used in HFT soft. Use y2007g geometry (last updated for AuAu in simu : http://drupal.star.bnl.gov/STAR/comp/prod/MCGeometry Follow these different steps : Produce AuAu MB 200GeV as background Produce 1 D0 per event Mix fz files from background and D0 Run the bfc to do the reco (with slow simulation) Analyze MuDst.root file (ie all reco. tracks) (with same macro used for real data analysis)
AuAu background detp geometry y2007g make geometry make gstar … swit 2 3 vsig 0.01 20.0 gkine -1 0 0 5 -6.3 6.3 0 6.28 -40.0 40.0 gfile o outfile.fz user/input user infile.nt trig 50 • Y2007g geom. • Vertex at 0.01 with = 20 cm • AuAu collisions in 0<pT<5 • 50 events
D0 production #***************************************************** # Input for gkine set geometry=y2007g set pid=$3 set tracks_per_event=1 set ptlow=0.1 set pthigh=5.0 set ylow=-1.1 set yhigh=1.1 set philow=0.0 set phihigh=6.28 #***************************************************** • This step produces a .fz file with D0’s and used a • vertex file (containing the PV point) for correct mixing