Current Status of the VTX analysis Takashi HACHIYA 2014/2/20 Radiation lab meeting

Analysis Status of c/b separation Primary purpose is Show the new (preliminary) result from the CuAu analysis at QM14 Finalize the AuAu and pp analysis as soon as possible It it not likely to show the final result of the AuAu at QM14 Analysis status for AuAu after QM12 Improving the DCA distribution using new production Tracking algorithm and chi-square(VTX-CNT) calculation was improved, as I showed at the previous meeting. Deadmap and Alignment were updated. Unstable channels were masked. Additional 30% data is available (which was not used for QM12 analysis) Repeating QM12 analysis with new cuts. New DCA unfolding method is being introduced (show later) 2014/2/20 Radiation lab meeting

Production Status Production DONE: Production plan Second Run11 Au+Au production is done A bug in the code killed the strip layers artificially It is desired to rerun the production Run12 Cu+Au production is done QA plot shows some VTX ladder have misalignment Studying how much the performance get worse. Production plan CuAu production for FVTX Run12 Pp 200 production for VTX (reproduction) Under discussion for the further production (Run11AuAu or Run14AuAu or) 2014/2/20 Radiation lab meeting

Mis-Alignment in CuAu Some mis-alignment were found (reported by Hidemitsu) Strip has a big mis-alignment in both phi and Z direction We are working what makes this mis-alignment People didn’t trust this QA plots. A bug in QA code? A bug in the alignment procedure? Human error? We found at least there is one human error There is a typo between iteration of the alignment (6mm shifted by hand) Phi residual (hit – track) Phi residual (hit – track) B0 west B0 east B1 west B1 east B0 west B0 east B1 west B1 east B2 west B2 east B3 west B3 east B2 west B2 east B3 west B3 east Out of Range 2014/2/20 Radiation lab meeting

Hadron DCA and chi2/ndf from CuAu & AuAu (minbias) The shape around the peak is similar for CuAu and AuAu DCA width is 84um (CuAu) and 78um (AuAu) Mis-alignment in CuAu remain a little? The background yield (flat area) is larger for AuAu Chi2/ndf show similar, but a bit wider for CuAu There is some mis-alignment in CuAu, but not so terribly bad We can use this CuAu production for the analysis 2014/2/20 Radiation lab meeting

DCA unfolding New method is being tested Status: Original : Fit DCA distribution for each pT slice independently New method: (andrew and alan) Fit DCA and pT distribution simultaneously Sweeping the input parameter space and looking for the maximum log likely food Similar method with what used for Jet reconstruction Status: Using a toy MC model, the new method can reproduce the input c/b distribution The AuAu result will be appeared soon using QM12 DCA distribution. We are working with p+p too 2014/2/20 Radiation lab meeting

Toy MC example Input Shape Unfolding result Input (B+D) Pythia shape Pameter space Unfolding The unfolded result reproduces the input shape. Good! More detail, please see https://www.phenix.bnl.gov/cdsagenda/askArchive.php?base=agenda&categ=a1495&id=a1495s1t1/moreinfo Testing with changing the parameter spaces First result using QA12 spectra is coming soon For the DATA unfolding, we plan to use pT spectra from ppg77(run4) and DCA (run11) 2014/2/20 Radiation lab meeting

Summary Analysis for AuAu and CuAu is on-going DCA unfolding New production data for AuAu and CuAu is available Mis-alignment effect is not so severe. DCA unfolding A toy MC test is in good shape First result using DATA is soon 2014/2/20 Radiation lab meeting

2014/2/20 Radiation lab meeting

Hadron DCA from CuAu & AuAu (minbias) The shape around the peak is similar for CuAu and AuAu DCA width is 84um (CuAu) and 78um (AuAu) Mis-alignment in CuAu remain a little? The background yield (flat area) is larger for AuAu 2014/2/20 Radiation lab meeting

Hadron Chi2/ndf w/ 4hits from CuAu & AuAu Chi2/ndf is similar and a little steeper for AuAu Mis-alignment in CuAu remain a little? ( same tendency with DCA) But AuAu has a large tail in log scale (right plot) I suspect that the background makes this tail (see next page) I will check this with the veto cut Here, Veto cut was not used. 2014/2/20 Radiation lab meeting

Centrality dependence of chi2/ndf CuAu AuAu ET distribution Chi2/ndf changes with centrality Central collisions have more tails (it seems that background makes the tail) I think we must use same multiplicity event when comparing the distribution. From ET distribution, ET (most central@CuAu) ~= ET(Mid %@ AuAu) This corresponds to the black @ CuAu and the red @ AuAu The shape is similar 2014/2/20 Radiation lab meeting

Hadron DCA2D vs phi in CuAu and AuAu Black line : mean position (profile of 2D hist) Track cut : 1<pT<2GeV/c, nhit>=3, chi2/ndf<3, CuAu AuAu Phi Phi No veto cut, Acceptance is more flat. GOOD! Peak position is mostly aligned for both CuAu and AuAu The CuAu looks a bit spreaded for the west (phi~ -0.5) The AuAu has a shift around phi=2.2. but almost out of acceptance We can tune the DCA position to be 0 by the recalibrator . (if it is desired) 2014/2/20 Radiation lab meeting

DCA unfolding Electron pT and DCA shape from B and D decays are calculated using the probability function (assuming PYTHIA - kinematics) Looking for the maximum log likely hood using this calculated template with changing input assumption Likely-hoot for pT and DCA are combined using a certain weight 2014/2/20 Radiation lab meeting