April12 DST calibration status Jochen Markert

Jochen Markert, Goethe Universität Au+Au at 1.23 GeV/u (Apr12 ) AuAu 1.23 GeV/u Facts: 557 hours beam Au on Au target (1.2 - 1.5) x 106 ions per second 8 kHz trigger rate 200 Mbyte/s data rate 7.3 x 109 events 140 x 1012 Byte of data DST Generations: online : alignment and params online + old gen0 : without prefit gen1 : prefit procedure dp 1.25 GeV CC 2 GeV/u pNb 3.5 GeV pp 1.25 GeV CC 1 GeV/u Ar+KCl pp 3.5 GeV Jochen Markert, Goethe Universität

Strangeness K0s K- L f NN excess energy 0.44 GeV only! First measurement at such low beam energy see Talks of: Katharina Manuel L f 29.11.2012

RICH – MDC spatial correlations Leptons e- e+ RICH – MDC spatial correlations see Talks of: Patrick Szymon Jochen Markert, Goethe Universität

Global vertex reconstruction First reconstructed during candidate search (no fit of drift times used) Second reconstruction based on fitted inner MDC segments: filtering + LSM fit (including Tukey weights) Third reconstruction based on fully reconstructed particles (same as segments) Resolution along z ~1 mm (depending on multiplicity) GSI target lab: B. Kindler et al., NIMP 655, 2011 Jochen Markert, Goethe Universität

Jochen Markert, Goethe Universität START Jochen Markert, Goethe Universität

Start detector calibration and T0 determination for Apr 12 DST StartX and StartY calibrated, file-wise – data in Oracle T0 determination based on three fastest particles in RPC/TOF from hit level  ready, implemented (used in gen1) cases: 0. StartX 1. StartY 2. Start X and Y (mean) HStart2Hit::getCorrFlag() nucleus Improvement: old method (first Start Hit taken) vs new approach (T0 selected based on TOF/RPC hits)  method works correctly BUT: Works only if beam particles are separated in time more than 3 ns !! S. Spataro

Start detector analysis – problem with T0 Limitations of the method based on TOF/RPC and Start: Works only if beam particles are separated in time more than 3 ns !! Still wrongly determined T0. Event selection: At least 5 protons in RPC with time larger than 1.5 ns (10-4 events) Plots from P.Tlusty We will mark such cases in StartHitFinder (more than 1 hit within 3ns window) by adding an additional flag: 3 or -2 Ultimate method should be based on fully reconstructed tracks (G. Kornakov) Reconstructed T0 from all tracks in single event compared to Start detector Fit result based on 1/sqrt(N) contribution from tracking and constant contribution from START. σ(Start)=60ps nucleus To be implemented in HYDRA – high level analysis. S. Spataro

Jochen Markert, Goethe Universität MDC Jochen Markert, Goethe Universität

Summer'2012 business: Autumn'2012 business: Development and Implementation of New Ghost Rejection Method for the Cluster Finder Level 9 (class „hmdclookuptb“ in the Hydra2) Autumn'2012 business: New 36 „Butterfly“ cuts in 36 Θφ-regions using real geometry, corresponding magnetic field (0.72) • Global Time Offset correction for each MDC day by day • Time Offset correction wire by wire by special procedure Olga Pechenova

Number of the ghost inner segments vs. Multiplicity (Simulation) Nghost/Nall_segm = 55.4% Nghost/Nall_segm = 8.0% Nghost/Nall_segm = 2.7% Black cluster finder level 10 + old ghost removing (Level10) Green cluster finder level 9 + old ghost removing (Level10) Red cluster finder level 9 + new ghost removing (Level9) Olga Pechenova

Comparison of the cluster finder Level 9 (red) and Level 10 (black). Simulation Efficiency vs. multiplicity Efficiency vs. multiplicity Clusters Fitted segments Efficiency vs. momentum Efficiency vs. momentum Clusters Fitted segments Olga Pechenova

The number of leptons, pions and protons 23% 17% 19% 21% Gen1 New Cal1, New Butterfly, New Procedure in Tracking (Vladimir) Leptons Leptons 17% 3o% Olga Pechenova

To do : Olga: tuning track finder and segment fitter parameters for inner and outer segments (layer coefficients, constant of uncertainty...... ~ 30 parameters) after all last changes New Ghost Rejection for the 2nd track finder iteration Tuning track parameters for the 2nd track finder iteration CAL2 optimized versions (Claudia) Mdc dE/dx calibration (Jochen)

Jochen Markert, Goethe Universität RPC Jochen Markert, Goethe Universität

RPC performance The time resolution with the code as it is now in HYDRA is better than 88 ps** (88 ps is the resolution of pions with βγ=3, MIPS) The correction of the position-time dependence still not implemented. This correction improves resolution up to 72 ps for MIPs pions. Efficiency: Pions over 94,6% All particles over 97% Possible improvements with information from PCand Double hit recovery method Fine charge-time dependence correction (5-10 ps) Fine position-time dependence correction (5-20 ps) Resolution is not divided by 2 G.Kornakov

TOF

TOF Not fully calibrated in gen1 DSTs, work in progress. charged hits multiplicity serving as LVL1 trigger: velocity from vs charge*mom TOF energy loss vs charge*mom: TOF of selected of p-: TOF-START resolution 209 ps Not fully calibrated in gen1 DSTs, work in progress. P.Tlusty

SHOWER

Shower gain calibration Take charge distribution for one single pad: Take global charge distribution integrated over all pads: Calculate gain = max_global / max_pad Maximum pos. from fit: max_pad Maximum pos. from fit: max_global S.Harabaz

After (gain calculated) Before (gain = 1) After (gain calculated) Charge maximum position as a function of pad: S.Harabaz

RICH,WALL RICH: pedestals calibrated WALL: work on the charge calibration to be finished

Future Plans Take advantage of all improvements since dst gen1 and run gen2 short after collab meeting. Do not wait for further tracking improvements or improved parameters (DST production takes ~1 week) calibrate in parallel MDC dEdx, work on algorithms schedule dst gen3 for February 2013 start working for efficiency parameters for simulations (our simulation is not tuned at all at the moment)

Thanks !

Backup

Real data Apr12 Difference in Mass Distribution: Level 9 – Level 10 RPC Sector1 – black Sector2 – red Sector4 - green Sector5 – blue Sector6 - magenta ToF Real data Apr12 Olga Pechenova

Autumn'2012 business: Cut good tracks – 0.26% Olga Pechenova Global Time Offset correction for each MDC day by day Time Offset correction wire by wire by iterative procedure Now we have 3 tables MdcCalParRaw in Oracle: Due to new Cal1 number of leptons increases up to 27%, pions - up to 16% ! New 36 „Butterfly“ cuts (36 Θφ-regions) using real geometry, corresponding magnetic field (0.72) Cut good tracks – 0.26% Cut ghost tracks – 87.2% Number of fully reconstructed tracks (in β vs mom) ↑ by 1%, efficiency ↑ (especially in low momenta region) II. New Procedure in Tracking (Vladimir) Total: Improvements in number of tracks, chi2, number of wires/track, tracking efficiency, number of leptons (up to 51%), pions (up to 23%) ! Olga Pechenova

Finding of Target Segment of the Event Vertex Apply threshold to the distributions to filter Find Target segment by best projection of all wires simultaneously Smooth distributions to find maximum with best precision After vertex fit all 12 target segments well separated