1 / 20

PHENIX Run 9: Goals and Performance Achievements in Polarized p+p Physics

The PHENIX experiment at Brookhaven National Laboratory focuses on advancing the understanding of proton spin through polarized proton-proton collisions at 500 GeV. Key objectives include measuring W± → e± cross-sections, analyzing single spin asymmetry with longitudinally polarized protons, and upgrading muon arm performance. Notably, the experiment emphasizes the role of gluons in proton spin via double longitudinal spin asymmetry. With significant data accumulation, PHENIX aims to enhance knowledge of spin dynamics while managing systematic uncertainties. The run demonstrates improved technologies like MUTRIG and RPC for effective detection.

lalo
Download Presentation

PHENIX Run 9: Goals and Performance Achievements in Polarized p+p Physics

An Image/Link below is provided (as is) to download presentation Download Policy: Content on the Website is provided to you AS IS for your information and personal use and may not be sold / licensed / shared on other websites without getting consent from its author. Content is provided to you AS IS for your information and personal use only. Download presentation by click this link. While downloading, if for some reason you are not able to download a presentation, the publisher may have deleted the file from their server. During download, if you can't get a presentation, the file might be deleted by the publisher.

E N D

Presentation Transcript

  1. Run 9 PHENIX Goals and Performance John Haggerty Brookhaven National Laboratory

  2. 500 GeV p+p Physics Goals • Detection and cross section measurement for W± →e± in central arms (|η|< 0.35, σ~20 pb) • Measure single spin asymmetry with longitudinally polarized p+p • Characterize upgraded muon arm performance at 500 GeV and understand backgrounds in forward W

  3. 200 GeV p+p Physics Goals • Primary goal is to elucidate the gluon contribution to proton spin • Double longitudinal spin asymmetry ALL is sensitive to ΔG • PHENIX particularly well suited for high statistics π0 • Control of systematic uncertainties vital as statistical uncertainties decrease • Other channels possible contingent on statistics (π±, η, direct photon)

  4. Neutral pion production asymmetry projection Expected uncertainty for 25 pb-1 60% polarization arXiv:0810.0694 (PRL)

  5. Muon arms upgrades • MUTRIG • Adds ability to trigger on muon momentum • RPC • Adds excellent timing resolution • Absorber • Reduces background

  6. Muon trigger upgrade

  7. MUTRIG performance • Good efficiency with 30 mV threshold • Operational in MUTR.N for the entire run • Installed for test in MUTR.S to cover RPC • Prototype trigger logic being tested Station 1 Station 2 Station 3 Minimum Ionizing Particle

  8. RPC • Why Resistive Plate Chambers? • Fast response • Good spatial resolution • Low cost, CMS experience • Engineering run for sectors in 2 planes on south arm

  9. RPC prototypes Already the ~3 ns time resolution, current draw, and hit rate have helped understand background From collision or out going beam From beam background

  10. Hadron Blind Detector • Windowless Cerenkov detector with CF4 avalanche/radiator gas (2 cm pads) • Designed for low mass dilepton pairs in heavy ions but commissioned in p+p CsI photocathode covering triple GEMs

  11. HBD performance Electrons from Dalitz pairs in the mass region below 150 MeV. The number of photoelectrons is ~22, more than 50% increase from Run 7 Single electrons Double electrons f-z matching 20 pe 40 pe

  12. PHENIX polarimeter RED : yell pol. ↑ BLUE : yell pol. ↓ RED : blue pol. ↑ BLUE : blue pol. ↓ • “Shower Max Detector” segment of the ZDC instrumented for rapid polarimetry • FEM’s reprogrammed to send discriminator data to FPGA so that 8*120 scaler channels can accumulate reasonable statistics in 5 minutes on L-R asymmetries Transverse (10371)

  13. Trigger and data acquisition Selected triggers logged to separate streams for “Fastrak” analysis DAQ and trigger evolution keep livetime ~90% while recording 7 kHz

  14. 500 GeV longitudinally polarized p+p • 43 physics fills in 28 days • 220 TB recorded physics • 50.2 pb-1 delivered • Polarization ~35% * Preliminary luminosity numbers—cross sections and acceptances still work in progress

  15. First half of 200 GeV longitudinally polarized p+p • 74 physics fills in first 5 weeks • 200 TB recorded • 30.2 pb-1 delivered • Polarization ~ 53%

  16. Longitudinal polarization at PHENIX

  17. Muon arm J/ψ N S N S 500 GeV 200 GeV Production of muon stream allowed us to see J/ψ during the run

  18. Central arm analyses Calorimeter gain changed by factor ~2 for 500 GeV W program Unsubtracted e+e- spectrum

  19. PHENIX in Run 9 • New detectors necessary for future spin running commissioned—MUTRIG, RPC • Hadron Blind Detector brought into operation • First polarized p+p collisions at 500 GeV • Substantial amount of data accumulated • Polarization must be higher for spin physics, but polarization is preserved to 250 GeV • First half of 200 GeV run duplicated the Run 6 data set

  20. Thanks It’s impossible to thank everyone who contributed to this huge 24x7 six month effort… MCR… ~300 PHENIX shift takers…everyone who contributed figures….

More Related