The ALICE EMCal Physics Performance Report Status Rene

The ALICE EMCal Physics Performance Report - Status Rene Bellwied (Wayne State University) EMCal Collaboration Meeting, Nantes, July 16 th, 2008

Purpose of the document Ø Originally requested by the Department of Energy and to be completed by Dec. 31 st, 2008, in order to formulate the physics scope of the U. S. contribution to ALICE. Ø Based on discussions with ALICE the EMCal PPR will become an official addendum to the existing ALICE PPR. Ø It will also serve as a reference for the upcoming EMCal Technical Design Report

Organization Ø Ø Report coordinator: Rene Bellwied (Wayne State) Six prioritized sub groups with group coordinators 1. ) jet reconstruction (Joern Putschke) 2. ) EMCal triggering (Mateusz Ploskon) 3. ) photons and gamma jets (Gustavo Conesa Balbastre) 4. ) electron and heavy quark tagging (Mark Heinz / Jennifer Klay) 5. ) particle identified jet measurements (Rene Bellwied) 6. ) jet correlations (Claude Pruneau) Ø Ø Ø Initially groups 1 and 6 will be merged until the jet reconstruction algorithm is optimized. Bi-weekly EVO meetings. Several face-to-face meetings planned around ALICE weeks, ALICE-US collaboration meetings, EMCal meetings Temporary web-page: http: //pdsfweb 01. nersc. gov/~bellwied/emcal-ppr. html Report to PWG-3, PWG-4 and ALICE Physics Board regularly (either the group coordinators or the report coordinator)

Working groups Ø Presently 37 members, almost evenly distributed over the groups, with priority to the first four groups. Ø Contributors from 14 institutions: l Yale, LBNL, Nantes, Wayne State, Grenoble, CERN, Jyvaskyla, ORNL, Tennessee, Creighton, Purdue, UT Austin, LLNL, Frascati

General strategy Ø For jet reconstruction, triggering, photon, and electron (heavy flavor jet) physics improve on the existing simulations as shown in the CD-2 final physics report. Ø For particle identified jet measurements and jet correlations develop a performance report and interface with multiple other detector components in ALICE (TPC, TRD, ITS, PHOS). Use EMCal as tag on same side and measure fragmentation on the away-side

Main goals for group 1: jet reconstruction Attempt to extend the reliability of jet finding algorithm to jet energies below 100 Ge. V. Important for single jets, crucial for jet correlations. Ø Optimize jet finding algorithm through comparison (k. TJet, Jet. An, Fast. Jet) Ø Optimize quenching simulations, estimate effects elliptic and radial flow, hadron corrections, electron conversions, jetenergy correction see Peter Jacob’s talk Ø

Main goals for group 2: jet triggering Attempt to extend the trigger efficiency for jet energies of 50100 Ge. V. Check effect of jet quenching Ø Optimize LVL-1 algorithm by taking altering patch size/geometry based on new mapping manipulations (elelctronics). Ø Optimize HLT through implementation of EMCal software and subsequent merging with TPC, TRD and ITS information. Ø

Main goals for group 3: direct photons and gamma-jets Isolation cut study, Pb. Pb quenched Optimize g/ 0 discrimination for direct photon and g-jet measurement (shower shape, isolation cut studies) Ø g-jet tagging in PHOS and EMCal down to Eg=20 -30 Ge. V in order to extract reliable FF on away side. see Gustavo’s talk Ø

Main goals for group 4: heavy quark tagging with electrons Show electron to heavy meson correspondence in AA collisions. Optimize e/h discrimination Ø Simulate signed DCA method for B-mesons Ø Physics: e, B (J/y+K or e+D) spectra, RAA, B-jets see Mark Heinz’s talk Ø

Main goals for group 5: particle identified jet measurements Correlate high momentum PID measurements (rd. E/dx and V 0 method) to triggered jet rates for single hadron or resonance and dihadron correlation measurements in jets and between di-jets. Ø Determine fragmentation fnunctions for rare hadrons and particle ratios (baryon/meson or particle/antiparticle) in jets in EMCal enhanced data samples and compare to quenching model predictions. Ø

Main goals for group 6: jet correlations di-jet angle di-jet energy correlation di-jet energy balance Simulate possibility of acoplanarity and jet shape measurements based on jet reconstruction resolution. Ø Compare jet axis correlations to leading particle correlations. Ø

Example for Groups 3/5/6: physics on the EMCal triggered away-side High momentum resonances in jets to determine chirality Markert, RB, I. Vitev, ar. Xiv: 0807. 1509) Ø Determine enhancement factors due to jet trigger and analysis improvements due to jet reconstruction Ø (C. Formation time of high p. T resonances Measure modified resonance in away-side jet

Next steps Ø Collect l coming in (see next slides) Ø Collect l simulation requests coming in (see next slides) Ø Obtain l work plans more physics-based Jet MC e. g. JEWEL

Example: work plan group 3 (Gustavo) Task Sub Task Who PID Re-evaluate PID parameters with last Ali. Root version SUBATECH, 1 person Re-study the g/p 0 discrimination SUBATECH, 1 person EMCAL (gamma) - Central barrel (conversion) 1 person combination for Inv, Mass of p 0 (not for PPR? ) Direct photons Isolation cut Gamma-jet Re-evaluate IC with larger amount of events, specially jet-jet, PYTHIA Gustavo Compare predictions for different generators and theory 1 person Decay photon subtraction with Invariant Mass 1 person Improve HI background rejection 1 person Estimate effect of jet-jet contamination 1 person Code implementation in Analysis Frame Gustavo

Example: work plan group 4 (Jennifer) Task Tools Manpower Statistics Revisit rates (higher stats) PYTHIA + Material --kinematics info 0. 5 person 100 k x 15 jet p. T bins PYTHIA/HIJING + Full simulation 0. 5 person Single e, 0 10 k x ~10 p. T ranges 100 k x 15 jet p. T bins + 10 k HIJING bkg Electron and E-Jet trigger PYTHIA/HIJING + Ali. EMCALTrigger, (rates/bkg) HLT Trigger Group? 100 k x 15 jet p. T bins + 10 k HIJING bkg Electron spectra/RAA (e B/D corresp. , compare to TPC and TPC+TRD) PYTHIA + Full simulation 1 person 100 k x 15 jet p. T bins 100 k x ~5 p. Thard bins each of MSEL 4 and MSEL 5 D/B Spectra/RAA (e+D, J/Psi+K, mis-ID) PYTHIA + Full simulation 1 -2 people 100 k x 15 jet p. T bins 100 k x ~5 p. Thard bins each of MSEL 4 and MSEL 5 B-jets (DVM, W, JETAN reco, FF, other tag methods) PYTHIA/HIJING + Full simulation 2 -3 people 100 k x ~5 p. Thard bins each of MSEL 4 and MSEL 5 50 -100 k W-boson decays 10 k HIJING bkg Re-check e-ID matching, p/E) (track-

Example Simulation requests Ø Ø Ideally with Ali. Root and through the GRID Group 2 l l l Ø Group 3 l l Ø 5 -200 Ge. V jet energy spectrum pp and Pb. Pb statistics for each of the bins remains to be determined 10% of planned running year statistic would be comfortable pp exists so mostly Pb. Pb Gamma (EMCAL/PHOS) – jet (quenched, not quenched jet-jet (quenched/not quenched) A couple of quenching scenarios? q= 20 and q=50, models PQM, PYQUEN, maybe JEWEL? Group 4 l see work plan

Summary Ø A dedicated effort to define the physics scope enhancement due to the EMCal in ALICE is underway. Ø We hope to complete the document within six months in close collaboration with the existing PWG’s in ALICE. Ø Any input, comments, suggestions, help is much appreciated.