MEIC: A Medium Energy Electron Ion Collider at Jefferson Lab QCD and Hadron Physics, Lanzhou March 30, 2013 R. D. McKeown Jefferson Lab College of William and Mary

2 Outline Introduction to Jefferson Lab Motivation for Electron Ion Collider -Science goals -Requirements and specifications MEIC design

3 Jlab: A Laboratory for Nuclear Science Fundamental Forces & Symmetries Hadrons from Quarks Medical Imaging Quark Confinement Structure of Hadrons Accelerator S&T Nuclear Structure Theory and Computation

4 Current Jefferson Lab Accelerator Complex A B C CEBAF Large Acceptance Spectrometer (CLAS) in Hall B Cryomodules in the accelerator tunnel Free Electron Laser (FEL) Superconducting radiofrequency (SRF) cavities Hall D (new construction)

5 12 GeV Upgrade Project Scope of the project includes: Doubling the accelerator beam energy New experimental Hall and beamline Upgrades to existing Experimental Halls Maintain capability to deliver lower pass beam energies: 2.2, 4.4, 6.6…. New Hall Add arc Enhanced capabilities in existing Halls Add 5 cryomodules 20 cryomodules Upgrade arc magnets and supplies CHL upgrade Upgrade is designed to build on existing facility: vast majority of accelerator and experimental equipment have continued use The completion of the 12 GeV Upgrade of CEBAF was ranked the highest priority in the 2007 NSAC Long Range Plan.

6 Hall D – exploring origin of confinement by studying exotic mesons Hall B – understanding nucleon structure via generalized parton distributions Hall C – precision determination of valence quark properties in nucleons and nuclei Hall A –form factors, future new experiments (e.g., SoLID and MOLLER) 12 GeV Scientific Capabilities

7 Present expectation (subject to rebaseline review): month installation May May Sept 2013 Hall A commissioning start Oct 2013 Feb 2014 Hall D commissioning start April 2014 Oct 2014 Halls B & C commissioning start Oct 2014 Oct 2015 Project Completion Dec 2016 FY12: reduction of $16M FY13: Pres Request – no restoration Rebaseline in progress Next DOE Project Review May, GeV Upgrade Project Schedule

8 Hall D & Counting House 12 GeV Project Status Hall D Drift Chamber Installation in all 4 Halls has begun Challenges with superconducting magnets for experiments All 7 magnets under contract Schedule delay a concern for two contracts Hall D solenoid cool-down is underway Upgrade Project 73% Complete, 85% Obligated Accelerator commissioning begins October 2013 Beam to Hall A in 2 nd Quarter of FY14 Beam to Hall D in 1st Quarter of FY15 Installation in all 4 Halls has begun Challenges with superconducting magnets for experiments All 7 magnets under contract Schedule delay a concern for two contracts Hall D solenoid cool-down is underway Upgrade Project 73% Complete, 85% Obligated Accelerator commissioning begins October 2013 Beam to Hall A in 2 nd Quarter of FY14 Beam to Hall D in 1st Quarter of FY15 Hall D Interior Hall C Dipole Magnet Coil SC Magnet Conductor Press

9 Beyond 12 GeV Upgrade Super BigBite Spectrometer (Approved for FY13-16 construction) - high Q 2 form factors - SIDIS MOLLER experiment (MIE – FY15-18?) - Standard Model Test SoLID Chinese collaboration CLEO Solenoid Enhancements of equipment in B, C, D (Leverage external investments)

10 JLab12: 21 st Century Science Questions What is the role of gluonic excitations in the spectroscopy of light mesons? Can these excitations elucidate the origin of quark confinement? Where is the missing spin in the nucleon? Is there a significant contribution from valence quark orbital angular momentum? Can we reveal a novel landscape of nucleon substructure through measurements of new multidimensional distribution functions? What is the relation between short-range N-N correlations, the partonic structure of nuclei, and the origin of the nuclear force? Can we discover evidence for physics beyond the standard model of particle physics?

11 12 GeV Approved Experiments by PAC Days More than 7 years of approved experiments

12 12 GeV White Paper arXiv: Executive Summary 2Meson Spectroscopy, Hybrid Mesons & Confinement 3The Internal Structure of Hadrons 4QCD and Nuclei 5The Standard Model and Beyond 6 Appendix A: Experimental Equipment

13 Electron Ion Collider 13 NSAC 2007 Long-Range Plan: “An Electron-Ion Collider (EIC) with polarized beams has been embraced by the U.S. nuclear science community as embodying the vision for reaching the next QCD frontier. EIC would provide unique capabilities for the study of QCD well beyond those available at existing facilities worldwide and complementary to those planned for the next generation of accelerators in Europe and Asia.” Jefferson Lab and BNL developing facility designs Joint community efforts to develop science case  white paper (2013)

NRC Decadal Study

15 Recent Documents

16 12 GeV With 12 GeV we study mostly the valence quark component An EIC aims to study gluon dominated matter. The Landscape of EIC mEIC EIC

17 EIC Science (I) EIC will complete our knowledge of the nucleon through exploration of the gluon-dominated regime at low x. How much spin is carried by gluons? Does orbital motion of sea quarks contribute to spin? -Generalized parton distributions (GPD) -Transverse momentum dependent (TMD) distributions What do the parton distributions reveal in transverse momentum and coordinate space?

18 EIC Science (II) Map the gluon field in nuclei What is the distribution of glue in nuclei? Are there modifications as for quarks? Can we observe gluon saturation effects? Study spacetime evolution of color charges in nuclei How do color charges evolve in space and time? How do partons propagate in nuclear matter? Can nuclei help reveal the dynamics of fragmentation? Search for physics beyond the standard model

19 EIC Requirements From the 2013 EIC White Paper:

20 EIC The Reach of EIC JLab 12 EMC/E665HERMES High Luminosity  cm -2 s -1 High Polarization  70% Low x regime x  Discovery Potential!

21 Polarized Luminosity x = Q 2 /ys (x,Q 2 ) phase space directly correlated with s (=4E e E p ) Q 2 = 1 lowest x scales like s Q 2 = 10 lowest x scales as 10s -1 current data w/ EIC data

22 Polarized Luminosity: SIDIS Major improvement over present data!

23 Medium Energy JLab Concept MEIC: 3-12 GeV on GeV ep/eA collider fully-polarized, longitudinal and transverse luminosity: up to few x e-nucleons cm -2 s -1 Upgradable to higher energies (250 GeV protons) Pre-booster Ion source Transfer beam line Medium energy IP Electron collider ring (3 to 12 GeV) Injector 12 GeV CEBAF SRF linac Warm large booster (up to 20 GeV) Cold ion collider ring (up to 100 GeV)

24 MEIC Design Report Posted: arXiv: Stable concept for 3 years Overall MEIC design features: Highly polarized (including D) Full acceptance & high luminosity Minimize technical risk and R&D “world’s first polarized e-p collider and world’s first e-A collider” EPJA article by JLab theory on MEIC science case (arXiv: ; EPJ A48 (2012) 92)

25 Design Features: High Polarization All ion rings (two boosters, collider) have a figure-8 shape Spin precession in the left & right parts of the ring are exactly cancelled Net spin precession (spin tune) is zero, thus energy independent Ensures spin preservation and ease of spin manipulation Avoids energy-dependent spin sensitivity for ion all species The only practical way to accommodate medium energy polarized deuterons which allows for “clean” neutron measurements This design feature permits a high polarization for all light ion beams (The electron ring has a similar shape since it shares a tunnel with the ion ring) Use Siberian Snakes/solenoids to arrange polarization at IPs longitudinal axis Vertical axis Solenoid Insertion Longitudinal polarization at both IPs Transverse polarization at both IPs Longitudinal polarization at one IP Transverse polarization at one IP Proton or Helium-3 beams Deuteron beam Slide 25

26 Design Features: High Luminosity Follow a proven concept: 2x10 34 /cm 2 /s – Based on high bunch repetition rate CW colliding beams – Uses crab crossing MEIC aims to replicate this concept in colliders w/ hadron beams The CEBAF electron beam already possesses a high bunch repetition rate Add ion beams from a new ion complex to match the CEBAF electron beam KEK-BMEIC Repetition rateMHz Particles per bunch (e - /e + ) or (p/e - ) / / 2.5 Beam currentA1.2 / / 3 Bunch lengthcm0.61 / 0.75 Horizontal & vertical β*cm56 / /2 to 4/0.8 Beam energy (e - /e + ) or (p/e - )GeV8 / / 5 Luminosity per IP, cm -2 s ~ 1.4 high bunch repetition rate small bunch charge short bunch length (  z ) small  * (  * ~  z )

27 MEIC Accelerator R&D: Electron Cooling Electron Cooling in Collider – proof of principle of concept & techniques  Cooling simulations are in progress (collaboration with Tech-X established through an SBIR grant)  ERL circulator cooler (linear optics and ERL) design has been completed  Fast RF kicker concept has been developed, plan to test with two kickers from SLAC  Test of beam-beam kicker concept at FNAL/ASTA facility and collaboration are in planning  Optics design of a cooler test facility based on JLab FEL ERL has been completed Solenoid (15 m) SRF injector dumper MEIC Electron cooler DechirperRechirper e-Cooler Test FEL A technology demonstration possible using JLab FEL facility eliminating a long return path could double the cooling rate (in center of figure-8) Required R&D: demonstrate ERL-based cooler concept by 2016 (at FEL/ERL conditions)

28 Proposed Cooling Experiments at IMP  Replacing the existing thermionic gun in the cooler by a JLab photo-cathode gun (Poelker)  Highly invasive to a user facility Proposed experiments Bunched electron beam to cool a DC ion beam (New phenomena: longitudinal bunch (Hutton)) Bunched electron beam to cool a bunched ion beams (need an RF cavity for bunching the ion beams) DC cooler Storage rings for Heavy ion coasting beam

29 Further ongoing MEIC Accelerator R&D Space Charge Dominated Ion Beam in the Pre-booster  Simulation study is in progress by Argonne-NIU collaborators Beam Synchronization  A scheme has been developed; SRF cavity frequency tunability study is in progress Beam-Beam Interaction  Phase 1 simulation study was completed Interaction Region, Chromaticity Compensation and Dynamic Aperture  Detector integration with IR design has been completed, offering excellent acceptance  Correction scheme has been developed, and incorporated into the IR design  Tracking simulations show excellent momentum acceptance; dynamic aperture is increased  Further optimization in progress (e.g., all magnet spaces/sizes defined for IR +/- 100 m) Beam Polarization  Electron spin matching and tracking simulations are in progress, achieving acceptable equilibrium polarization and lifetime (collaboration with DESY)  New ion polarization scheme and spin rotators have been developed (collaboration with Russian group) – numerical demonstration of figure-8 concept with misalignments ongoing Electron Cloud in Ion Ring Ion Sources (Polarized and Universal)

30 solenoid electron FFQs 50 mrad 0 mrad ion dipole w/ detectors ions electrons IP ion FFQs 2+3 m 2 m Detect particles with angles below 0.5 o beyond ion FFQs and in arcs. Need 4 m machine element free region detectors Central detector Detect particles with angles down to 0.5 o before ion FFQs. Need 1-2 Tm dipole. EM Calorimeter Hadron Calorimeter Muon Detector EM Calorimeter Solenoid yoke + Muon Detector TOF HTCC RICH RICH or DIRC/LTCC Tracking 2m 3m 2m 4-5m Solenoid yoke + Hadronic Calorimeter Very-forward detector Large dipole 20 meter from IP (to correct the 50 mr ion horizontal crossing angle) allows for very-small angle detection ( o ). Need 20 m machine element free region Full MEIC: Full Acceptance Detector 7 meters Three-stage detection

31 MEIC Point Design Parameters Detector typeFull acceptance high luminosity & Large Acceptance ProtonElectronProton Electron Beam energyGeV605 5 Collision frequencyMHz750 Particles per bunch Beam CurrentA Polarization%> 70~ 80> 70 ~ 80 Energy spread10 -4 ~ 37.1~ RMS bunch lengthmm Horizontal emittance, normalizedµm rad Vertical emittance, normalizedµm rad Horizontal and vertical β*cm10 and 2 4 and 0.8 Vertical beam-beam tune shift Laslett tune shift0.06Very small0.06 Very small Distance from IP to 1 st FF quadm Luminosity per IP, cm -2 s

32 EIC Realization Imagined Assumes endorsement for an EIC at the next NSAC Long Range Plan Assumes relevant accelerator R&D for down-select process done around 2016 Activity Name GeV Upgrade FRIB EIC Physics Case NSAC LRP EIC CD0 EIC Machine Design/R&D EIC CD1/Downsel EIC CD2/CD3 EIC Construction

33 Summary There has been excellent progress on developing the EIC science case over the last 2 years, with important contributions from both the BNL and JLab communities. White paper now available. We anticipate an NSAC Long Range Plan in the next 2-3 years – need to realize a recommendation for EIC construction. MEIC design is stable and mature. R&D planning in progress, with good opportunities for collaboration. We are hopeful that an international collaboration can develop to advance the science and technology of electron ion colliders.

34 Announcement EIC14 An International Workshop for Accelerator science and Technology for Electron-ion Collider March 24 – 28, 2014 Newport News, Virginia, USA Y. Zhang, IMP Seminar 34 Welcome to Virginia!