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Concept for an Electron Ion Collider detector at eRHIC

Concept for an Electron Ion Collider detector at eRHIC. ● Physics goals ● detector design ● performance studies . Jin Huang (BNL) for the PHENIX collaboration. Based on the ePHENIX Letter of Intent, arXiv:1402.1209 [ nucl -ex] . Physics goals: nucleon as a laboratory for QCD.

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Concept for an Electron Ion Collider detector at eRHIC

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  1. Concept for an Electron Ion Collider detector at eRHIC ● Physics goals ● detector design ● performance studies Jin Huang (BNL)for the PHENIX collaboration Based on the ePHENIX Letter of Intent, arXiv:1402.1209 [nucl-ex]

  2. Physics goals: nucleon as a laboratory for QCD Outlined in EIC white paper, arXiv:1212.1701 Jin Huang <jhuang@bnl.gov> • The compelling question: How are the sea quarks and gluons, and their spins, distributed in space and momentum inside the nucleon? • Deliverable measurement using polarized electron-proton collisions • The longitudinal spin of the proton, through Deep-Inelastic Scattering (DIS) • Transverse motion of quarks and gluons in the proton, through Semi-Inclusive Deep-Inelastic Scattering (SIDIS) • Tomographic imaging of the proton, through Deeply Virtual Compton Scattering (DVCS) • Leading detector requirement: • Good detection of DIS electrons • Momentum measurement and PID of hadrons • Detection of exclusiveproduction of photon/vector mesons and scattered proton

  3. h g* e’ q e Physics goals: nucleus as a laboratory for QCD Outlined in EIC white paper, arXiv:1212.1701 Jin Huang <jhuang@bnl.gov> • The compelling questions: • Where does the saturation of gluon densities set in? • How does the nuclear environment affect the distribution of quarks and gluons and their interactions in nuclei? • Deliverable measurement using electron-ion collisions • Probing saturation of gluon using diffractive process • Nuclear modification for hadron and heavy flavor production in DIS events • Leading detector requirement: • Large calorimeter coverage to ID diffractive events • ID of hadron and heavy flavor production

  4. One realization of electron ion collider: RHIC → eRHIC at Brookhaven National Lab RHIC as today: world’s only polarized proton collider and support large variety of HI beam Jin Huang <jhuang@bnl.gov>

  5. One realization of electron ion collider: RHIC → eRHIC at Brookhaven National Lab eRHIC: reuse one of the RHIC rings + high intensity electron beam • 250 GeV polarized proton • 100 GeV/N heavy nuclei • 15 GeV polarized electron • luminosity ≥ 1033 cm-2s-1 PHENIX interaction point at eRHIC Courtesy: eRHIC pre-CDR Jin Huang <jhuang@bnl.gov>

  6. PHENIX upgrade plan Current PHENIX sPHENIX ePHENIX • Comprehensive upgrade • Central rapidity: Calorimetry and tracking optimized for probing QGP using jets • Forward : new opportunity • A capable EIC detector based on PHENIX upgrade • New collaboration will be formed ~2000 ~2020 ~2025 Time Jin Huang <jhuang@bnl.gov> Two sets of spectrometer for central and forward, respectively Operating for ~10 years 130+ published papers to date

  7. The sPHENIX detector Baseline detectors for sPHENIX sPHENIX MIE, http://www.phenix.bnl.gov/plans.html Jin Huang <jhuang@bnl.gov> sPHENIX: major upgrade to the PHENIX experiment Baseline consists of new large acceptance EMCal+HCal built around recently acquired BaBar magnet. Additional tracking also planned Study QGP using jets and heavy quarksat RHIC energy region MIE submitted to DOEStrong support from BNL Serve as a good foundationfor eRHIC detector

  8. ePHENIX Detector Concept Costed: sPHENIX MIE + 75M$(including overhead + contingency) R (cm) η=+1 R (cm) HCal η=-1 HCal EMCal Aerogel z ≤ 4.5m -1.2 EMCal & Preshower RICH Outgoing hadron beam DIRC TPC η= 4 EMCal BBC e- p/A GEM Station2 GEMs GEMs Station1 GEM Station3 GEM Station4 z (cm) ZDC z≈12 m Roman Pots z≫10 m Jin Huang <jhuang@bnl.gov> • -1<η<+1 (barrel) : sPHENIX + Compact-TPC + DIRC • -4<η<-1 (e-going) : Crystal calorimeter + GEM trackers • +1<η<+4 (h-going) : • 1<η<4 : GEM tracker + Gas RICH • 1<η<2 : Aerogel RICH • 1<η<5 : EM Calorimeter + Hadron Calorimeter • Along outgoing hadron beam: ZDC and roman pots

  9. A SIDIS event in ePHENIXGEANT4 event display for SIDIS @ x≈5×10-3 and Q2=10 (GeV/c)2Integrated in PHENIX software framework IP Hadron Calo. Aerogel Babar coil EM Calo. Gas RICH EM Calo. Hadron Calo. DIRC TPC e-, 10 GeV/c GEMs DIS e- BBC p, 250 GeV/c EMCal Jin Huang <jhuang@bnl.gov>

  10. Magnet and field BaBar solenoid packed for shipping, May 17 2013 Longer Magnet Babar Tracking resolution based on field calculation Babar magnet VS older version sPHENIX magnet Jin Huang <jhuang@bnl.gov> • Went through ~10 types of forward field magnet design over few years • BaBar superconducting magnet became available • Built by Ansaldo→ SLAC ~1999 • Nominal field: 1.5T • Radius : 140-173 cm • Length: 385 cm • Field calculation and yoke tuning • Three field calculator cross checked: POISSION, FEM and OPERA • Favor for ePHENIX tracking • Designed for homogeneous B-field in central tracking • Longer field volume for forward tracking • Higher current density at end of the magnet -> better forward bending • Work well with RICH in ePHENIX yoke: Forward & central Hcal + Steel lampshade • Ownership officially transferred to BNL

  11. Tracking and PID detector overview e-going GEMs -4.0<η<-1 TPC -1<η<+1 DIRC -1<η<+1 h-going GEMs 1<η<2 gas RICH 1<η<4 Aerogel RICH 1<η<2 IP Geant4 model of detectorsinside field region TPC GEMs Tracking eGEM Hadron PID RICH η e- Fringe field 1.5 T main field Fringe field p/A p/A e- Jin Huang <jhuang@bnl.gov>

  12. Tracking system GEM LEGS-TPC, B. Yu, et al., 2005 Main detector: Driving factor: e-going GEM Electron ID TPC Kinematic h-going GEM Hadron PID dp/p~1%×p • Additional dp/p term: • dp/p≲3% for 1<η<3 • dp/p~10% for η=4 dp/p~0.1%×p Jin Huang <jhuang@bnl.gov> • Good momentum resolution over wide range, -3<η<+4 • GEM tracker for forward region • d(rφ) = 100 μm; 50 μm for very forward region • GEM-based TPC for barrel region • 10μs max drift time and no-gate needed • Thin support structure, e.g. fibre-reinforced polymer • Space available for inner silicon tracker upgrade

  13. Hadron PID Overview IP Detector coverage for hadron PID Aerogel RICH 1<η<2 DIRC -1.2<η<+1 Gas RICH 1<η<4 SIDIS x-Q2 coverage with hadron PID in two z-bins e- p TPC GEMs eGEM RICH Mirror Hadron PID Coverage Jin Huang <jhuang@bnl.gov> • DIRC • Based on BaBar DIRC design plus compact readout • Collaborate with TPC dE/dx for hadron ID in central barrel • Aerogel RICH • Approximate focusing design as proposed by Belle-II • Collaborate with gas RICH to cover 1<η<2 • Gas RICH: next slides • Possible upgrade in electron-going direction

  14. Courtesy: Stonybook group Beam test data StonyBrook group Fermilab T-1037 data Gas RICH- The Design R (cm) η=1 RICH Mirror RICH Gas Volume (CF4) IP Ring size (A.U.) Focal plane HBD detector η=2 spherical mirror center η=3 Entrance Window η=4 Z (cm) Jin Huang <jhuang@bnl.gov> • High momentum hadron ID require gas Cherenkov • CF4 gas used, similar to LHCb RICH • Beautiful optics using spherical mirrors • Photon detection using CsI−coated GEM in hadron blind mode- thin and magnetic field resistant • Active R&D: • Generic EIC R&D program • recent beam tests by the stony brook group

  15. Ring radius ± 1σ field effect for worst-case region at η~+1 Gas RICH - performance in ePHENIX A RICH Ring: Photon distribution due to tracking bending only Field effect has very little impact for PID R R < 52 mrad for C4F10 Dispersion ΔR <2.5 mrad π K p η~1 PID purity at η=4 (most challenging region w/ δp) • Strong fringe field unavoidableTuned yoke → magnetic field line most along track within the RICH volume → veryminor ring smearing due to track bending • Reached good hadron ID to high energy EMCal Purity Aerogel track RICH η~4

  16. Calorimeters Electron purity after EMCal PID Fraction of DIS event with good electron ID Jin Huang <jhuang@bnl.gov> • EM Calorimeter • Measure electrons and photons • e-going: PbWO4 crystal calorimeter, dE/E~1.5%/√E • Barrel and h-going: W- and Pb-scint. sampling calorimeter, dE/E~12%/√E • GEANT simulation show electron background of photon conversion is negligible • Hadron Calorimeter • Cover -1<η<+5, great for ID diffractive events • Also serve as magnetic field return

  17. Beam line detector Jin Huang <jhuang@bnl.gov> Beam line detector design is integrated to accelerator lattice ZDC -> detector neutron -> categorization of the eA collision type and geometry “Roman pots”→ measure deflection of proton in exclusive productions → Kinematic determination for proton tomography One layout is shown here. More studies needed in iterations with accelerator

  18. ePHENIX gluon helicity projection Physics performance: longitudinal spin structure of proton ePHENIX electronkinematics survivability High x and Q2 region will be better determined using info from hadron final states Jin Huang <jhuang@bnl.gov> ePHENIX will significant expand the x-Q2 reach for longitudinal spin measurement EM calorimeter and tracking deliver good kinematic determination and particle ID Precise evaluation of gluon and sea quark spin

  19. Physics performance: Transverse structure of nucleon • SIDIS Sivers Asymmetries • DVCS Jin Huang <jhuang@bnl.gov> Deliver clean measurement for SIDIS and DVCS Significantly expand x-Q2 reach and precision for such measurements Extract sea quark and gluon’s transverse motion and their tomographic imaging inside polarized nucleons Sensitive to the orbital motion of quark inside proton

  20. Physics performance: Probing gluon saturation Probing saturation region in electron kinematics ID diffractive events using ePHENIX calorimeters η of most forward going particle Eff./Purity with ηMAX cut 20 Jin Huang <jhuang@bnl.gov> ePHENIX is at the kinematic range to inspect the transition to gluon saturation region and their nuclear size dependent Large H-cal coverage (-1<η<+5) provide clean ID of diffractive events with reasonable efficiency through the rapidity gap method Delivering high precision diffractive-to-total cross section ratio measurement, which is very sensitive to the gluon saturation

  21. h g* e’ q e Physics performance: parton propagation through nuclear matter Energy transfer ν VS Q2 coverage ePHENIX projection for nuclear modification ratio SIDIS in e-A collisions probe color neutralization and harmonization as it propagate through nuclear matters ePHENIX provide a set of flexible handles : struck quark’s energy and flavor, virtuality of DIS, geometry of the collision, specie of nuclei. Also possible for D-meson production through kinematical reconstruction of identified decay products

  22. Physics before the EIC era: Use as forward detector in RHIC pp/pA collisions IP ePHENIX GEM + H-Cal → Forward jet with charge sign tagging → Unlock secrets of large AN in hadron collisions + reuse current silicon tracker & Muon ID detector → polarized Drell-Yan with muons → Critical test of TMD framework + central detector (sPHENIX) → Forward-central correlations → Study cold nuclear matter in pA  Single jet in GEANT4 pT = 4.1 GeV/c, eta = 3 p/A p↑ GEMs Hadron Calo. Jin Huang <jhuang@bnl.gov> The ePHENIX forward detector can be constructed earlier → a unique forward program with RHIC’s pp/pA collision The collaboration is drafting a white paper to discuss the physics program

  23. Summary Tracking Hadron PID EM and hadron calorimeter η Jin Huang <jhuang@bnl.gov> Plan: PHENIX → sPHENIX → ePHENIX ePHENIX : a comprehensive detector concept for PHENIX interaction point at eRHIC A new collaboration will be formed for carrying out its construction and physics program. Abundant opportunities. Active study on going : successful review in Jan 2014, detector R&D, simulations Read more: arXiv:1402.1209 and https://www.phenix.bnl.gov/plans.html

  24. Backup Jin Huang <jhuang@bnl.gov>

  25. Forward tracking strategies Jin Huang <jhuang@bnl.gov>

  26. e-going hadron ID or what we missed Jin Huang <jhuang@bnl.gov>

  27. Geant Tracking resolution – 1<η<3 • dp/p ~ (Multiple scattering term) + (Tracker resolution term)*p Tracker resolution term, 1< η <2.5: d(Sagitta2) = 120μm for 100 μm tracker resolution 2.5< η <4: d(Sagitta2) = 60μm for 50 μm tracker resolution • Multiple scattering term • Displayed without RICH • With RICH tank (2/3 of tracks): ~20% (rel.) worse • With RICH tank + Readout (1/3 of tracks): ~50% (rel.) worse Jin Huang <jhuang@bnl.gov>

  28. Cherenkov angles choices Jin Huang <jhuang@bnl.gov>

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