Recent Progress toward a HighLuminosity EIC at JLab

Recent Progress toward a High-Luminosity EIC at JLab 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. In support of this new direction: We recommend the allocation of resources to develop accelerator and detector technology necessary to lay the foundation for a polarized Electron Ion Collider. The EIC would explore the new QCD frontier of strong color fields in nuclei and precisely image the gluons in the proton. ”

2007: The ELectron Ion Collider at JLab Concept • NSAC LRP: EIC = a 3 -10 Ge. V on 25 -250 Ge. V ep/e. A collider fully-polarized, longitudinal and transverse JLab implementation: luminosity ~7 x 1034 cm-2 s-1 JLab implementation: 4 Interaction Regions (IRs) large asymmetry between electron/ion energies reduced luminosity (factor of 10) at low Ecm new ion complex with Ep ~ 250 Ge. V is expensive Electron Cooling ELIC IR Snake New Ion Complex: 30 -250 Ge. V Protons 15 -125 Ge. V/n Ions IR Snake CEBAF: 3 -11 Ge. V Electrons

Recent Progress toward a High-Luminosity EIC at JLab Brought to you by the MEIC/ELIC Study Group Nuclear Physics (exp) (thy) Tanja Horn Charles Hyde Franz Klein Pawel Nadel-Turonski Vadim Guzey Christian Weiss CASA Alex Bogacz Slava Derbenev Geoff Krafft Yuhong Zhang (+ help from many others) With input from Larry Cardman Andrew Hutton Hugh Montgomery Tony Thomas

EIC@JLab High-Level Science Overview • Hadrons in QCD are relativistic many-body systems, with a fluctuating number of elementary quark/gluon constituents and a very rich structure of the wave function. • With 12 Ge. V we study mostly the valence quark component, which can be described with methods of nuclear physics (fixed number of particles). • With an (M)EIC we enter the region where the many-body nature of hadrons, coupling to vacuum excitations, etc. , become manifest and theoretical methods are those of quantum field theory.

The Science of an (M)EIC Nuclear Science Goals: How do we understand the visible matter in our universe in terms of the fundamental quarks and gluons of QCD? Overarching EIC Goal: Explore and Understand QCD Four Major Science Questions (paraphrased from NSAC LRP 07): 1) What is the three-dimensional spatial landscape of nucleons? 2) What is the internal spin landscape of nucleons? 3) What is the role of gluons in nuclei? 4) What governs the transition of quarks and gluons into pions and nucleons? Or, Elevator-Talk EIC science goals: Map the spin and 3 D quark-gluon structure of protons (show the nucleon structure picture of the day…) Discover the role of gluons in atomic nuclei (without gluons there are no protons, no neutrons, no atomic nuclei) Understand the creation of the quark-gluon matter around us (how does E = Mc 2 work to create quarks/anti-quarks and hadrons? )

(M)EIC@JLab: Basic Considerations • Optimize for nucleon/nuclear structure in QCD - access to sea quarks/gluons (x > 0. 01 or so) - deep exclusive scattering at Q 2 > 10 - any QCD machine needs range in Q 2 s = 1000 or so to reach decade in Q 2 high luminosity, >1034 and approaching 1035, essential lower, more symmetric energies for resolution & PID • Not driven by gluon saturation (small-x physics) … … avoid fundamental conflict of “classical” EIC • “Sweet spot” for - electron energies from 3 to 5 Ge. V (minimize synchrotron) - proton energies ranging from 30 to 60 Ge. V - but larger range of s accessible (Ee = 11 Ge. V, Ep = 12 Ge. V) • Decrease R&D needs, while maintaining high luminosities - Potential future upgrade to high-energy collider, but no compromising of nucleon structure capabilities

A High-Luminosity EIC at JLab - Concept MEIC Coverage Legend: MEIC = EIC@JLab 1 low-energy IR (s ~ 200) 3 medium-energy IRs (s < 2600) ELIC = high-energy EIC@JLab (s = 11000) (limited by JLab site) Use CEBAF “as-is” after 12 -Ge. V Upgrade

A High-Luminosity Electron-Ion Collider for Nuclear Physics at JLab – main parameters • MEIC is ring-ring collider with • electron energies ranging from 3 to 11 Ge. V • proton energies ranging from 12 to 60 Ge. V • Luminosity L ~ few x 1034, approaching 1035 cm-2 s-1 • MEIC requires less R&D, parameters within reach (? ) • MEIC estimated cost ~ Half of ELIC • Most components reusable at higher energies • Physics: Nucleon/nuclear structure in QCD (Gluon and sea quark imaging of the nucleon, nucleon spin, nuclei in QCD, QCD vacuum and hadron structure) • Natural extension of 12 Ge. V • Consistent with NSAC Long-Range Plan

2009: A High-Luminosity Medium-Energy Collider MEIC (MEIC) for Nuclear Physics at Jlab fully-polarized, longitudinal and transverse energy range more optimized for JLab-type NP luminosity ~ few x 1034 cm-2 s-1 over range of Ecm more symmetric energies reduced cost, ~ half of ELIC less R&D needs New Ion Complex: 30 -60 Ge. V Protons 15 -30 Ge. V/n Ions CEBAF: 3 -11 Ge. V Electrons

MEIC/ELIC Figure-8 Collider Ring Footprint Medium Energy IP Snake Insertion MEIC parameters Low Energy IP 60° Arc 157 Straight section 150 Insertion section 10 Circumference • MEIC luminosity is limited by • Synchrotron radiation power of e-beam requires large ring (arc) length • Space charge effect of p-beam requires small ring length • Multiple IRs require long straight sections. Recent thinking: start with 18 meter detector space for all IRs to make life easier (? ) • Straight sections also hold other required components (electron cooling, injection & ejections, etc. ) City of NN Length (m) 634 WM State City of NN MEIC Footprint (~600 m) ELIC Footprint (~1800 m) SURA CEBAF

EIC@JLab – Interaction Region Assumptions Can one use pluses of green field (M)EIC/ELIC in IR design? - Four Interaction Regions available - novel design ideas promise high luminosity - more symmetric beam energies “central” angles - figure-8 design optimized for spin (no impact on IR design) Main IR assumptions (make life simple…): - concentrate on one IR as main-purpose detector - separate diffractive/low-Q 2 “Caldwell-type” detector from main-purpose detector (if needed) - define relatively long (18 meter) fixed detector space (albeit with loss in luminosity) - use flexibility in RF frequency to advantage (high RF for main detector physics? , low for e. A diffraction? , etc. )

(M)EIC@JLab Interaction Region Concept IR 1: General Purpose detector (but not diffractive/low-Q 2? ) IR 3: Diffractive/Low-Q 2 detector Medium Energy IP Snake Insertion 60° p Low Energy IP e IR 2: Polarimetry etc. IR Regions: +/- 9 meter IR 4: Low Energy detector Medium Energy: 30 -60 on 3 -5 (11) Low Energy: 12 on 3 -5 [sqrt(s) only factor of three higher than 12 -Ge. V program]

Why an Electron-Ion Collider? • Longitudinal and Transverse Spin Physics! - 70+% polarization of beam and target without dilution - transverse polarization also 70%! • Detection of fragments far easier in collider environment! - fixed-target experiments boosted to forward hemisphere - no fixed-target material to stop target fragments - access to neutron structure w. deuteron beams (@ pm = 0!) • Easier road to do physics at high CM energies! - Ecm 2 = s = 4 E 1 E 2 for colliders, vs. s = 2 ME for fixed-target 4 Ge. V electrons on 12 Ge. V protons ~ 100 Ge. V fixed-target - Easier to produce many J/Y’s, high-p. T pairs, etc. - Easier to establish good beam quality in collider mode Longitudinal polarization FOM Target p d fdilution, Pfixed_target f 2 P 2 EIC 0. 2 0. 8 0. 03 0. 5 0. 4 0. 5 0. 04 0. 5 fixed_target

What Ecm and Luminosity are needed for Deep Exclusive Processes? New Roads: § r and f Production give access to gluon GPD’s at small x (<0. 2) § Deeply Virtual Meson Production @ Q 2 > 10 Ge. V 2 disentangles flavor and spin! Well suited processes for the EIC transverse spatial distribution of gluons in the nucleon Can we do such measurements at fixed x in the valence quark region? This IS important if we really want a full picture of orbital motion… fixed x: s ~ s/Q 2 (Mott) x 1/Q 4 (hard gluon exchange)2 s L Q 2 reach DVCS Q 2 reach (e, e’p) 12 -Ge. V 21 1035 =7 =7 EIC@JLab 1000 3 x 1034 ~100 ~17

50 fb-1 120 100 xmin ~ 10 -4 gluon saturation MEIC 40 20 0 xmin ~ 10 -3 xmin ~ 10 -2 1 DIS nucleon structure 60 quarks, gluons in nuclei 80 10 exclusive, electroweak processes ECM (Ge. V) Science reach as function of ECM and integrated luminosity 1 year ~ 20 weeks @ 50% eff. @ 1 x 1034 = 6 x 1040 ~ 60 fb-1 need multiple conditions: Longitudinal, Transverse, 1 H, 2 H, 3 He, heavy A, low, high Ecm sin 2θW 100 ∫L dt (fb-1)

(M)EIC@JLab: Where we are (or, were for 8 m detector space) JLab/12 HERMES ENC/GSI COMPASS ra D (M)EIC ft Luminosity (1033 s-1 cm-2) Polarized ep Facilities 1) 2) 3) 4) Staged e. RHIC s (Ge. V 2) Plot assumptions: (M)EIC Luminosities optimized at 5 Ge. V on 12 Ge. V and 5 Ge. V on 60 Ge. V. Detector/DAQ/electronics limits the luminosity to 1035. Scale to higher electron beam energies (up to 11 Ge. V) at fixed synchrotron limit. Luminosity for staged e. RHIC at 2 on 250 is similar as for 4 Ge. V on 250 Ge. V. Note: chose more conservative 18 m detector space estimated L = few x 1034, work in progress - Design provides excellent luminosity for 200 < s < 1200 (x = 0. 0008 @ Q 2 = 1) (x = 0. 01 @ Q 2 = 12) - Good luminosity (1033 or more) down to s = 100 and up to s = 2640 (can access gluons down to x = 0. 001 or so)

Recent Progress toward a High-Luminosity EIC at JLab - High-Level Summary What science goals are accessed/appropriate? 1) Gluon and sea quark (transverse) imaging of the nucleon 2) Nucleon Spin (DG vs. ln(Q 2), transverse momentum) 3) Nuclei in QCD (gluons in nuclei, quark/gluon energy loss) 4) QCD Vacuum and Hadron Structure and Creation Energies s luminosity (M)EIC@Jlab Up to 11 x 60 150 -2650 Few x 1034 Future ELIC Up to 11 x 250 11000 Close to 1035 • Energies and figure-8 ring shape and size chosen to optimize polarization and luminosity • Try to minimize headaches due to synchrotron and large leaps in state-of-the-art through R&D • 4 Interaction Regions, with function and size optimized to “decouple” detector from accelerator – can optimize later to increase luminosity

General Info MEIC/ELIC web pages are now accessible to all: http: //www. jlab. org/meic General EIC web page: http: //web. mit. edu/eicc/ Bi-weekly meetings on EIC accelerator/IR design in ARC 728 (in collaboration with CASA/Accelerator), and bi-weekly meetings on EIC science/detector in CC F 326/7 All meetings can be accessed by all, also remotely. (1 st meeting is call-in, 2 nd meeting is EVO video conferencing) If interested, please subscribe to meic@jlab. org Friday, 9: 30 – 11: 00 am

Backup Slides

s = 2650 sufficient to transcend into region of large rise of gluon density MEIC@JLab coverage

Science Matrix – alternate version Luminosity (s-1 cm-2) 1036 x ~ Q 2/ys 1035 EW 1034 DES SIDIS 1033 DIS 1032 10 DIFF 10000 s (Ge. V 2) Saturation 100000

CTEQ Example at Scale Q 2 = 10 Ge. V 2 “dip” in u, d pdf’s at x ~ 0. 01 (@ Q 2 =10 Ge. V 2) s ~ 1000 appropriate

The Venerable (Nuclear) EMC Effect F 2 A/F 2 D 10 -4 “EMC Effect” 10 -3 10 -2 Space-Time Structure of Photon 10 -1 x < (5 times 10 -3) for saturation in shadowing to start? Need about decade in Q 2 to verify LT vs. HT of effects want to push down to x ~ 0. 0005 (@ Q 2 = 1) w. MEIC. Ecm = 10 – 45 (s = 100 – 2000) is in the right ballpark for nucleon/nuclear structure studies

Reaching Saturation: EIC Options Energies s s. EIC/s. HERA boost in “virtual” x reach gluon density boost over HERA at Q 2 = const 11 x 24 1050 1/96 1. 51 4 4 x 100 1600 1/63 1. 71 6 10 x 100 4000 1/25 2. 25 15 G ~ A 1/3 x s 0. 3 (A = 208)

Four Electron-Ion Collider Facilities Considered e. RHIC ELIC Electron e-cooling (RHIC II) Cooling IR PHENIX IR Main ERL (2 Ge. V per pass) Snake STAR MANUEL Add electron beam (COSY ring) to GSI/HESR Four e-beam passes LHe. C Snake

Four Electron-Ion Collider Facilities Considered EICx 2: L > 1 x 1033 cm-2 s-1 Ecm = 20 -100+ Ge. V • Variable energy range • Polarized and heavy ion beams • High luminosity in energy region of interest for nuclear science Nuclear science goals: • Explore the new QCD frontier: strong color fields in nuclei • Precisely image the sea-quarks and gluons to determine the spin, flavor and spatial structure of the nucleon. MANUEL@FAIR: L > 1 x 1033 cm-2 s-1? Ecm = 13 Ge. V LHe. C: L = 1. 1 x 1033 cm-2 s-1 Ecm = 1. 4 Te. V • Add 70 -100 Ge. V electron ring to interact with LHC ion beam • Use LHC-B interaction region • High luminosity mainly due to large g’s (= E/m) of beams High-Energy physics goals: • Parton dynamics at the Te. V scale - physics beyond the Standard Model - physics of high parton densities (low x) • Add 3 Ge. V electron accelerator to interact with FAIR ion beam Nuclear science goal: • Precisely image the sea-quark and gluon structure of the nucleon.

ELIC/MEIC in JLab Site

Recent Progress with a High-Luminosity EIC at JLab • 2007 LRP: EIC = a 3 -10 Ge. V on 25 -250 Ge. V ep/e. A collider fully-polarized, longitudinal and transverse luminosity ~ 1033 -1034 cm-2 s-1 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. ”