RHIC Spin Experiments L.C. Bland, for the RHIC spin collaboration Brookhaven National Laboratory Workshop on Hadron Structure and Spectroscopy Paris, March 1-3, 2004 Long-term goals Polarized protons in RHIC STAR and PHENIX Results from first polarized proton collisions Plans for the future Summary RHIC Spin Collaboration Organization RHIC Spin Collaboration (Spokesman: G. Bunce) Develops overall spin plan; forum to coordinate spin issues for RHIC accelerator and experiments. Spin physics is an integral part of the goals of the STAR, PHENIX and pp2pp experiments. RHIC Accelerator Spin Group (Spokesman: T. Roser, Project Manager: W. Mackay) Accelerator physics for spin (Siberian Snakes, Spin Rotators,`Spin Flipper); polarized ion source; polarimeters. RIKEN and RIKEN/BNL Research Center (Group Leaders: H. Enyo, G. Bunce) Funds spin physics equipment; develops polarimetry; organizes spin workshops; supports young physicists. STAR Spin Physics Working Group (Conveners: L. Bland, H. Spinka) PHENIX Spin Physics Working Group (Conveners: Y. Goto, K. Barish) pp2pp Experiment (Spokesman: W. Guryn) BNL Groups: RHIC Spin Group (Group Leader: G. Bunce); RBRC/Nuclear Theory Develop / exploit spin capability of RHIC; coordinates accelerator / experiment activities; complete measurements; members in STAR, PHENIX and pp2pp experiments. Laboratory / University participation BRAHMS collaboration, PHENIX collaboration, pp2pp collaboration, STAR collaboration New groups: Cal Tech, Colorado, Illinois, MIT The Relativistic Heavy Ion Collider at Brookhaven National Laboratory R-HI New state of matter QGP De-confinement polarized proton Nucleon Spin Structure Spin Fragmentation pQCD RHIC is a QCD lab PHENIX STAR Brhams pp2pp Equipment to be installed after FY03 Polarized Proton Operation at RHIC Equipment/developments for runs 2 (1/02) and 3 (3/03 5/03) Helical dipole snake magnets CNI polarimeters in RHIC,AGS fast feedback *=1m operataion spin rotators longitudinal polarization Gluon Contribution to the protons spin qg Compton scattering with polarized protons provides a direct measure of gluon polarization. Coincident detection of and away-side jet event determination of initial-state partonic kinematics. Flavor Decomposition of the protons spin W production probes flavor structure analogous to deep inelastic scattering. Polarized proton beams allows the measurement of (the expected large) parity violation in W production. Forward ,e detection (dominated by production of W s with large longitudinal momentum) gives direct probe of quark (antiquark) polarization: projections STAR EndCap EMC (1/3) BBC West EMC (Half) Barrel BBC East Forward Pion Detectors (E & W) STAR Au+Au, s = 200 GeV NN See NIM A499 (2003) STAR features large acceptance Run 2003 configuration Complete endcap EMC towers in place for run 2004 Complete barrel EMC towers in place for run 2005 STAR STAR Electromagnetic Calorimeters Invariant Mass (GeV/c ) 2 0 (p T > 3 GeV/c) Recon- struction with Barrel EMC Barrel EMC: 2400/4800 towers installed for 2003, with SMD but not yet preshower readout Endcap EMC: 240/720 towers installed; no SMD, preshower or postshower readout yet STAR PHENIX Detector Philosophy: High rate capability & granularity Good mass resolution and particle ID Sacrifice acceptance 0 reconstruction and high p T photon trigger: EMCal: | | 200 MeV/c Require | p| T > 1 GeV/c Represent distribution with Gaussian (s) + constant (b) hadrons p + p + h + X ( =3.8) E (GeV) Statistical uncertainties only Significant back-to-back correlations for all x F, in agreement with PYTHIA Quantitative comparison to models determinations of k T and j T smearing in p + p STAR PRELIMINARY DATA Forward =3.8 Midrapidity tracks Vector sum of all tracks with: -1 < < +1 p T > 200 MeV/c Require | p| T > 1 GeV/c STAR Conclusions Forward from p + p collisions NLO pQCD (and PYTHIA LO + parton showers) agrees with inclusive cross section measurement, unlike lower s data PYTHIA says large-x F, large- come from 2 2 and 2 3 parton scattering with small contributions from soft processes Back-to-back particle correlations with midrapidity charged particles qualitatively agree with PYTHIA Forward meson production at RHIC energies comes from hard partonic scattering Spin effects Comparison with d + Au Flavor tagging Important result for: STAR 01/22/04 1 PP FY04 Run Goal 55 bunches with 1x10 11 per bunch, emittance: 15 mm-mrad Average current/ring: 70mA Peak luminosity: 11x10 30 cm -2 s -1 Average luminosity: 6.0x10 30 cm -2 s -1 * = 1m at STAR and PHENIX Polarization at store >=0.40 Ultimate goal for PP FY2004: 55 bunches w. 2x10 11 per bunch 112 bunches w. 1x10 11 per bunch Achieved in PP FY03 55 bunches w. 0.7x10 11 per bunch, emittnace: 15 mm-mrad Average current/ring: 48mA Peak luminosity: 6.0x10 30 cm -2 s -1 Average luminosity: 3.0x10 30 cm -2 s -1 * = 1m at STAR and PHENIX Polarization at store: 0.30 01/22/04 1 Strategies to achieve the goal Ameliorate beam-beam effect New working point Reducing beam-beam driven resonances by adjusting phase advance between IRs IR non-linearity correction Pushing and learning the limit of the achievable proton intensity NEG coating beam scrubbing Beta squeeze along the ramp Avoid hysteresis effect when beta squeeze at flattop, so the machine is more reproducible Better model engine Ironing the tune & chromaticity along the ramp(Johannes) PLL: feedforward Smaller emittance to gain luminosity Multi-bunch injection Gain the average luminosity Wolfram Fischer RHIC Run-4 Au+Au Luminosity evolution As of 02/22/04 22:00 Star 0.9 Phobos 0.3 Brahms 0.4 Delivered 762 ( b) -1 to Phenix 128 ( b) -1 last week [best week: 153] minimum projection physics target maximum projection [projection and target for 14 weeks of physics run] Atomic Hydrogen Beam Source separation magnets (sextupoles) H 2 dissociator Breit-Rabi polarimeter RHIC beam focusing magnets (sextupoles) RF transitions holding field magnet p recoil arms recoil detectors January 21, 2004Alessandro Bravar Recoil spectrometer 2004 RUN WILL INSTALL 6 DETECTORS ON BLUE BEAM ONLY will have design azimuthal coverage one Si layer only smaller energy range reduced bkg rejection power B January 21, 2004Alessandro Bravar The road to P beam Requires several independent measurements 0 target polarization P target (Breit-Rabi polarimeter) 1 A N for elastic pp in CNI region: A N = 1 / P target N 2 P beam = 1 / A N N 1 & 2 can be combined in a single measurement: P beam / P target = - N / N 3 CALIBRATION: A N pC for pC CNI polarimeter in detector kinematical range: A N pC = 1 / P beam N (1 +) measured almost simultaneously alternating p and C CNI polarimeters 4 BEAM POLARIZATION: P beam = 1 / A N pC N to experiments at each step pick-up some measurement errors: transfer calibration measurement requires < 10 7 pp CNI events Where we are in the program Siberian Snakes demonstrated to work P beam at RHIC injection energy now 0.4 / goal is 0.7 Fast polarimeters in AGS and RHIC demonstrated to work P beam transfer AGS RHIC demonstrated to work P beam preserved in RHIC ramp to 100 GeV demonstrated to work P beam preserved in RHIC ramp to 250 GeV to do P beam maintained during RHIC store 14 hours observed longitudal P beam at PHENIX,STAR / local polarimetry demonstrated to work P beam / P beam to 5% commission gas jet in 2004; 10% in 2004; 5% in 2005 L avg week to 20(50) pb -1 at s=200(500) GeV now ~0.3 pb -1 at s=200 GeV Polarization reversal of stored beam to do Summary of RHIC Spin Program as of 3/04 Measured cross sections and particle correlations from p + p collisions at s = 200 GeV are consistent with expectations of pQCD. Analyzing powers observed for mulitple processes from p + p collisions at s = 200 GeV. Spin rotator magnets were successfully tuned to produce longitudinal polarization at PHENIX and STAR interaction regions. First measurements of A LL for midrapidity and jet production are underway and will continue for RHIC runs 4,5 sensitivity to gluon polarization. Polarized gas jet target is ready for commissioning and is planned for the calibration of the RHIC beam polarization via pp elastic scattering.