STAR Goals and Performance 2009 Run STAR W

STAR Goals and Performance, 2009 Run STAR W. B. Christie, BNL Outline RHIC/AGS Users Meeting June 4, 2009. • Summary of STAR Goals for RHIC Run 9 • Brief Summary of STAR Changes for Run 9 • STAR Performance in 500 Ge. V pp run • STAR Performance in ongoing 200 Ge. V pp run • Summary Testing TOF trays New TPC Electronics

Executive Summary of STAR Goals for Run 9 STAR • Commission major detector upgrades (TPC, TOF, Trigger) • Physics and preparation for the future at 500 Ge. V - Establish local polarimetery of transverse components - W cross-section - W AL: 10 pb-1 sampled with Longitudinal polarization 50% • pp 2 pp @ 200 Ge. V: ½ week for complete transverse program • If the run is extended: highest priority 200 Ge. V p+p - BUR: 50 pb-1 sampled, 60% Polarization, FOM P 4 L = 6. 5 pb-1 2

STAR Run 9 500 Ge. V program (W production) • STAR Projected performance / assumptions - STAR 500 Ge. V program Assumed only minimum projection / Time needed in STAR for commissioning work: ~10 pb-1 (recorded) Primary goal: Develop local polarimetry in STAR at 500 Ge. V ( ZDC) : DONE • Physics Goal 1: First W measurement in STAR at mid-rapidity : Establish signal (Extensive full GEANT simulations completed of W signal and QCD background events - Feasibility demonstrated!) • Physics Goal 2: First AL W measurement (W+) • Other opportunities: Jets / Di-Jets at low x Assumption: FOM = P 2 L ~ 2. 5 pb-1 P ~ 0. 5 Ldelivered ~ 30 pb-1 Lrecorded ~ 10 pb-1 3

Expectations on W signal from Simulation Software: e/h separation (Run 9 500 Ge. V, 10 pb-1 sampled luminosity ) Development of e/h algorithm at mid-rapidity (BEMC) started in preparation of Run 9 based on full W/QCD simulations Very promising to establish a clear W signal in Run 9! 20 to 60 Ge. V Isolation cuts Jacobian peak for e+- 4 Mid-rapidity STAR

STAR Run 9 200 Ge. V program (Gluon polarization) • STAR Projected performance / assumptions - STAR 200 Ge. V program Reach BUR goal in 10 weeks! Precision inclusive measurements, in particular inclusive jet production Di-Jet production - Probe x dependence of Δg(x) Substantial improvement of gluon polarization reflected in highest PAC recommendation! Assumption: FOM = P 4 L ~ 6. 5 pb-1 P ~ 0. 6 , Ldelivered ~ 100 pb-1 Lrecorded ~ 50 pb-1 Need: 10 weeks 5

Run 9, STAR 200 Ge. V pp Goals STAR Goal in the BUR: L = 50 pb-1, P= 60% : FOM 6. 5 pb-1 Projected improvement in x g from Run 9 • Reduce ALL uncertainties a factor of ~4 • Will provide much stronger constraints on gluon polarization • RHIC becomes the dominant constraint on g. 6

Goals from p+p 200 Ge. V for heavy ion physics STAR Goal in the BUR: L = 50 pb-1 • Reference for Au in RHIC II era: last chance for a few years Factor 5 x increase in L for rare probes vs. run 6 • Non-photonic electrons: extend correlation signatures for B vs. D • J/Ψ: use TOF and EMC for precision • Upsilon: 1 st attempt to separate higher states • γ-hadron: currently p+p is limit on IAA Large minbias dataset with DAQ 1000: 300 M Has not been possible in previous years, due to DAQ limitations Fundamental baseline for untriggerable probes: D, dileptons, hadrons • DAQ 1000 allows STAR to take these data sets in parallel with Spin program • Particle ID from TOF adds significant improvement in Signal/Background for many of these topics • Low mass in center of STAR for this data set, relative to Run 6 7

STAR Run 9 200 Ge. V program (pp 2 pp) • Unique opportunity of diffractive physics in STAR : pp 2 pp Vertical Roman Pots • Physics: Elastic scattering / Central production / Single diffraction dissociation • Need to reach small t values to measure small masses of interest large β* = 20 m • required, special optics and beam scraping needed pp 2 pp setup moved to STAR and integrated (Run 8) / Commissioning of trigger and Si detectors ongoing / Need: Dedicated run of 4 -5 days (incl. 2 days setup) 8

DAQ 1000 Completed for Run 9 STAR • All new Readout Boards (RDO, ~ 200) were received, tested, and installed. FEE Board • All FEE boards (~5000) were received, tested, and installed. Completed on schedule. • All LV power supplies were removed, modified, reinstalled, and tested. RDO Board Modifying LV Supplies • The new TPC (aka TPX) electronics was fully installed, commissioned and operational in Run 9! Installing FEES/RDOs FEE Testing First sector installed & Tested TPC deadtime ~ 1% for TPC readout rates of ~ 500 Hz! 9 Boards Arriving

10 DAQ 1000 TPC Electronics Upgrade Complete STAR New TPC Low Voltage supplies installed New TPC readout computers installed New TPC FEEs, RDOs, cables, and fibers installed

TOF Test Stand one of two Gas Manifolds STAR • Goal for FY 08 Shutdown was to get somewhere between ½ (I. e. 60) and ¾ (I. e. 90) TOF trays installed for Run 9. • We ended up slightly better than the high end goal, with 94 (out of 120) TOF trays installed. • Plan to complete remaining tray installation this summer. 11

STAR Trigger Changes for Run 9 New Hardware: All the “standard” trigger detectors converted to new QT Digitizer electronics - BBC, ZDC, VPD: New Crate - PXZ, MTD, pp 2 pp: New Crate both crates get new PECL -> ECL for TAC boards - FPDE, FPDSMD: New crate TOF: 5 new TDSMI boards (built by TOF/BNL) Data path uses DRORC to L 2 TCU: Planned for new board with new interface board (Still being commissioned) Recabling of BEMC DSM tree to close Jet Trigger hole at = 0. Miscellaneous fiber routing changes and additions. 12

STAR Run 9 500 Ge. V program, QA/achievements • STAR ZDC SMD Local Polarimetry ZDC-SMD: Scintillator strip shower max. detectors Two independent analyses to cross check results (UCLA/LBNL and ANL/Valpo) Large asymmetry seen during transverse running period (AN ~ 0. 075 at 500 Ge. V) From recent 200 Ge. V transverse store we extract AN ~ 0. 04. For next 500 Ge. V pp run we plan to get this polarimeter data into scaler system. 13

STAR Run 9 500 Ge. V program, QA/achievements • STAR Run 9 500 Ge. V Status - W Trigger 13 Ge. V 7. 3 Ge. V 2009 STAR data 100 K L 2 W-trig eve 25 -45 Ge. V ET W-trigger: HT>7. 3 Ge. V ET & L 2: 2 x 2 >13 Ge. V, 2 -3 Hz ~97% of barrel towers participate in trigger 14

STAR Run 9 - Sampled Luminosity, 500 Ge. V STAR Goal 10 pb-1 FOM goal (2. 5 pb-1) not met due to low Beam polarizations Achieved FOM ~ 1. 5 pb-1 Total sampled luminosity ~ 10. 7 pb-1, goal achieved. ~ 10 pb-1 of additional delivered luminosity used for ZDC Polarimetry studies (Not necessary in future years, will get ZDC polarimeter into scalers) 15

16 STAR Run 9 - 500 Ge. V period - Status ~ 50 -55% at injection ~ 35 -40% at store Yellow Beam Polarization ~37% Blue Beam • Spin rotator tuning: - Trans. Component reduced to 10% - No significant lifetime issue of Y and B beam observed Need to understand the de-polarization in RHIC. C-AD plans to continue studies this year via APEX 16

Example of rates for production 2009_200 Ge. V_Single BBC coincidence rate ~ 350 k. Hz STAR 17 N. B. TPC ~ 1% dead, taking events at ~ 500 Hz!

Run 9 200 Ge. V, Data samples accumulated to date (6/3/09) Lsampled Goal = 50 pb-1 STAR FOM (P 4 L) Goal = 6. 5 pb-1 FOM to date ~ 1. 1 pb-1 Lsampled to date = 12 pb-1 Goal is 300 Mevts of VPDMB • The accumulation of the BUR requested FOM to complete the STAR 200 Ge. V Spin program is a high priority for STAR. • Will have to complete the remainder of this data set in a future run. • Heavy Ion data set will be significant leap forward for STAR. 18

Expected results for Heavy Ion portion of Run 9 200 Ge. V pp run STAR Factor ~ 3 x (vs 5) increase in L for rare probes vs. run 6 - Non-photonic electrons: extend correlation signatures for B vs. D - J/Ψ: use TOF and EMC for precision - Upsilon: 1 st attempt to separate higher states - γ-hadron: currently p+p is limit on IAA Large minbias dataset with DAQ 1000: 300 M - Has not been possible in previous years, due to DAQ limitations - Fundamental baseline for untriggerable probes: D, dileptons, hadrons All of the above data sets get additional significant improvement with TOF PID and the low mass configuration of STAR • Results from new High Level Trigger (HLT) initiative • Use capabilities afforded with DAQ 1000 to do Real time tracking and invariant mass reconstruction • Results shown represent sampling a small fraction of the run 9 data (few weeks, tight cuts). 19

Summary STAR First 500 Ge. V Run a success: - Established and calibrated local polarimetry for 500 Ge. V beams with the ZDC SMD - Achieved BUR goal of 10 pb-1 sampled luminosity. Expect first RHIC W measurement - First chance to determine environment STAR will have to deal with for 500 Ge. V program. Collider backgrounds essentially non-existent. Charge loading in TPC significant. W triggers commissioned. - Low polarization, and hence missed FOM goal, makes W AL extraction problematic - Collider has more work to do to increase polarization 200 Ge. V Run a mixed bag: -Portions of this data set, relevant as Heavy Ion references, will far surpass all earlier STAR pp data sets - Due to luminosity lifetime issues it looks like we’ll fall short of our Spin sampled luminosity and FOM goals by a factor of a few. Will need to complete in future run. Expanded STAR Capabilities: - New, fast TPC electronics an unqualified success! - New capability allows STAR to simultaneously run multiple physics programs and sample majority of delivered luminosity. - New TOF system (94/120 in Run 9, rest this summer) adds significant PID capability for STAR data sets. Large increase in Signal/Background for many analyses. Looking forward to first STAR pp 2 pp run and data set at end of Run 9. 20