The Electron Ion Collider Project April 12, 2011 DIS2011, Newport News, VA Abhay Deshpande

Related Talks: 4/12/2011 Abhay Deshpande Overview of the US EIC Project 2 An update on eRHIC acceleraor V. Litvinenko Design status of of MEIC at JLab V. Morozov PDFs today and tomorrow M. Stratmann Theory overview of e-A physics at the EIC J. Jalilian-Marian Experimental overview of e-A physics at the EIC T. Ullrich A new Monte Carlo event generator for eA collisions at low-x T. Toll Theory overview of e+p physics at an EIC J. Qiu Experimental overview of e+p physics at an EIC H. Gao Imaging sea quarks and gluons at the EIC T. Horn Ep physics opportunities at eRHIC T. Burton Transverse single-spin asymmetry measurement from SIDIS at an EIC M. Huang Weak mixing angle measurement at EIC Y. Li PHENIX and STAR Detector Upgrades (for use as Stage 1 eRHIC detector) E. O’Brien, J. Dunlop … And of course, low-x physics at LHeC is a physics connection

Success of pQCD at High Q: Jet Cross section Input: – F 2 (x,Q 2 ) structure function from HERA – Next to Leading Order perturbative QCD 4/12/2011 Abhay Deshpande Overview of the US EIC Project 3 Compilation: J. Putschke

QCD definitely correct, but… Lattice QCD Starting from QCD lagrangian  Static properties of hadrons: hadron mass spectrum 4/12/2011 Abhay Deshpande Overview of the US EIC Project 4 Calculations possible in perturbation theory assuming coupling is small, at high Q Problematic at low Q  fast rise of  S (Q) No guidance on partonic dynamics

Do we really “understand” QCD? While there is no reason to doubt QCD, our level of understanding of QCD remains extremely unsatisfactory: both at low & high energy Can we explain basic properties of hadrons such as mass and spin from the QCD degrees of freedom at low energy? What are the effective degrees of freedom at high energy? – How do these degrees of freedom interact with each other and with other hard probes? – What can we learn from them about confinement & universal features of the theory of QCD? After ~20+ yrs of experimental & theoretical progress, we are only beginning to understand the many body dynamics of QCD 4/12/2011 Abhay Deshpande Overview of the US EIC Project 5 R. Venugopalan

Generation of Mass – Gluons in QCD Protons and neutrons form most of the mass of the visible universe 99% of the nucleon mass is due to self generated gluon fields gluon dynamics identical – Similarity between p, n mass indicates that gluon dynamics is identical & overwhelmingly important Lattice QCD supports this 4/12/2011 Abhay Deshpande Overview of the US EIC Project 6 Higgs Mechanism, often credited with mass generation, is of no consequence Bhagwat et al.

HOW WELL DO WE UNDERSTAND GLUONS? What is the role of gluons at high energy? 4/12/2011 Abhay Deshpande Overview of the US EIC Project 7

Gluon distribution at low-x understood? Indefinite rise Indefinite rise artifact linear – Could this be an artifact of using of linear DGLAP in gluon extraction? – Infinite high energy hadron cross section? How would we find out? How would we find out? – Need theory development – Need experimental measurements at lower x! 4/12/2011 Abhay Deshpande Overview of the US EIC Project 8 No higher energy e-p collider than HERA!  other than “LHeC” OR  Use Nuclei: naturally enhance the densities of partonic matter Why not use Nuclear DIS at highest available energy? No higher energy e-p collider than HERA!  other than “LHeC” OR  Use Nuclei: naturally enhance the densities of partonic matter Why not use Nuclear DIS at highest available energy?

Low-x, higher twist & Color Glass Condensate 4/12/2011 Abhay Deshpande Overview of the US EIC Project 9 McLerran, Venugopalan… See Review: F. Gelis et al.,, arXiv: ) non-linear Small coupling, high gluon densities  Saturation Scale Q S (x,Q 2,A) Method of including non-linear effects in DGLAP equation  Small coupling, high gluon densities  Saturation Scale Q S (x,Q 2,A)  Some form of saturation, including Color Glass Condensate No unambiguous experimental evidence yet, but many smoking guns (HERA, RHIC & now LHC!) Could be explored cleanly in future with a high energy electron-Nucleus Collider Could be explored cleanly in future with a high energy electron-Nucleus Collider Kowalski Teany PRD 68: Kowalski Teany PRD 68:

UNDERSTANDING NUCLEON SPIN: WHAT ROLE DO GLUONS PLAY? 4/12/2011 Abhay Deshpande Overview of the US EIC Project 10

Evolution: Our Understanding of Nucleon Spin ? 1980s 1990/2000s We have come a long way, but do we understand nucleon spin? 4/12/ Abhay Deshpande Overview of the US EIC Project

Status of “Nucleon Spin Crisis Puzzle” know We know how to determine  and  g precisely: data+pQCD – ½ (  ) ~ 0.15 : From fixed target pol. DIS experiments not large as anticipated in the 1990s, but measurements & precision needed at low & high x – RHIC-Spin:  g not large as anticipated in the 1990s, but measurements & precision needed at low & high x 4/12/2011 Abhay Deshpande Overview of the US EIC Project 12 PHENIX

 Q 2 =10 GeV 2 Global analysis: DIS, SIDIS, RHIC-Spin Uncertainly on  G large at low x 4/12/2011 Abhay Deshpande Overview of the US EIC Project 13 de Florian, Sassot, Stratmann & Vogelsang Present positive  g Low x measurements =Opportunity! Low x measurements =Opportunity!

Status of “Nucleon Spin Crisis Puzzle” know We know how to measure  and  G precisely using pQCD – ½ (  ) ~ 0.15 : From fixed target pol. DIS experiments not large as anticipated in the 1990s, but measurements & precision needed at low & high x – RHIC-Spin:  G not large as anticipated in the 1990s, but measurements & precision needed at low & high x Orbital angular momenta: Generalized Parton Distributions (GPDs): H,E,E’,H’ – Quark GPDs: & – low x  J G  will need the future EIC! Would it not be great to have a (2+1)D tomographic image of the proton…. (2: x,y position and +1:momentum in z direction)? Would it not be great to have a (2+1)D tomographic image of the proton…. (2: x,y position and +1:momentum in z direction)? – Transverse Momentum Distributions, GPDs of Quarks & Gluons… full understanding of transverse and longitudinal hadron structure including spin! 4/12/2011 Abhay Deshpande Overview of the US EIC Project 14

The Proposal: Future DIS experiment at an Electron Ion Collider : A high energy, high luminosity (polarized) ep and eA collider and a suitably designed detector [2] [3] [1] Measurements: [1]  Inclusive [1] and [2] or [3]  Semi-Inclusive [1] and [2] and [3]  Exclusive Inclusive  Exclusive Low  High Luminosity Demanding Detector capabilities

EIC : Basic Parameters 10 5 E e =10 GeV (5-30 GeV variable) E p =250 GeV ( GeV Variable) Sqrt(S ep ) = 100 (30-200) GeV Sqrt(S ep ) = 100 (30-200) GeV X min = ; Q 2 max = 10 4 GeV Beam polarization ~ 70% for e,p,D, 3 He Luminosity L ep = cm -2 s -1 Luminosity L ep = cm -2 s -1 Minimum Integrated luminosity: Minimum Integrated luminosity: – 50 fb -1 in 10 yrs (100 x HERA) – Possible with cm -2 s -1 – Recent projections much higher Nuclei: 100 (140) p->U; E A = (140) GeV/N 63 (75) Sqrt(S eA ) = (75) GeV L eA /N = cm -2 s -1 4/12/2011 Abhay Deshpande Overview of the US EIC Project 16

Machine Designs Details in Talks by V. Litvinenko & V. Morozov eRHIC at Brookhaven National Laboratory using the existing RHIC complex ELIC at Jefferson Laboratory using the Upgraded 12GeV CEBAF Both planned to be STAGED

MEIC : Medium Energy EIC Three compact rings: 3 to 11 GeV electron Up to 12 GeV/c proton (warm) Up to 60 GeV/c proton (cold) low-energy IP polarimetry medium-energy IPs 4/12/2011 Abhay Deshpande Overview of the US EIC Project 18 Exists

ELIC: High Energy & Staging StageMax. Energy (GeV/c) Ring Size (m) Ring TypeIP # pepe Medium ColdWarm3 High ColdWarm4 Serves as a large booster to the full energy collider ring Arc Straight section 4/12/2011 Abhay Deshpande Overview of the US EIC Project 19

V.N. Litvinenko eSTAR ePHENIX Coherent e-cooler Beam dump Polarized e-gun New detector 0.6 GeV 30 GeV GeV GeV GeV GeV 3.05 GeV 7.95 GeV Linac 2.45 GeV Linac 2.45 GeV 100 m 25.1 GeV 20.2 GeV 15.3 GeV 10.4 GeV 30.0 GeV 5.50 GeV GeV eRHIC: polarized electrons with E e ≤ 30 GeV will collide with either polarized protons with E e ≤ 325 GeV or heavy ions E A ≤ 130 GeV/u eRHIC staging: All energies scale proportionally Small gap magnets 5 mm gap GeV 4/12/2011 Abhay Deshpande Overview of the US EIC Project 20

4/12/2011 Abhay Deshpande Overview of the US EIC Project 21

nucleuselectron proton nucleus eSTAR See J. Dunlop’s talk ePHENIX See E. O’Brien’s talk 4/10/11 Abhay Deshpande on EIC Collaboration's Perspective 22

Emerging eRHIC Detector Concept 4/12/2011 Abhay Deshpande Overview of the US EIC Project high acceptance -5 <  < 5 central detector good PID and vertex resolution (< 5  m) tracking and calorimeter coverage the same  good momentum resolution, lepton PID low material density  minimal multiple scattering and bremsstrahlung very forward electron and proton detection  dipole spectrometers Forward / Backward Spectrometers: E. Aschenauer et al. BNL EIC Task Force & EIC Collaboration

eRHIC IRs, β *=5cm, l*=4.5 m Up to 30 GeV e - beam 325 GeV p beam Spin-Rotator 10 mrad, with crab crossing L=1.4x10 34 cm -2 s -1, 200 T/m gradient 0.45 m Nb 3 Sn 200 T/m Star detector ©Dejan Trbojevic 90.m 325 GeV p beam Exploit LARP development of Nb 3 Sn SC quads with 200 T/m gradient Integrated with “new” detector design. Field-free electron pass thru hadron triplet magnets  minimal SR background. IR combined function magnet design See talk by Litvinenko’s

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. detectors Detect particles with angles down to 0.5 o before ion FFQs. Need 1-2 Tm dipole. Central detector 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 (<0.3 o ) Detector & IR Design: ELIC Nadel-Turonski, Horn, Ent And EIC Collaboration 4/12/2011 Abhay Deshpande Overview of the US EIC Project 25

Impact of EIC…. “golden measurements” Science of EIC: Institute of Nuclear Theory (INT) Program at U. of Washington: Sep-Nov 2010 Organizers: D. Boer, M. Diehl, R. Milner, R. Venugopalan, W. Vogelsang See the INT workshop for details of all studies Details in the EIC talks in this conference…. 4/12/2011 Abhay Deshpande Overview of the US EIC Project 26

Summary: Science of EIC: Precise Investigations of the “Glue” 4/12/2011 Abhay Deshpande Overview of the US EIC Project 27

Spin program at the EIC: 4/12/2011 Abhay Deshpande Overview of the US EIC Project 28 Science Deliverable Basic Measurement Uniqueness Feasibility Relevance Requirements spin structure at small x contribution of Δ g, ΔΣ to spin sum rule inclusive DIS ✔ need to reach x= large x,Q 2 coverage about 10fb -1 full flavor separation in large x,Q 2 range strangeness, s(x)-s(x) polarized sea semi-inclusive DIS ✔ very similar to DIS excellent particle ID improved FFs (Belle,LHC,…) electroweak probes of proton structure flavor separation electroweak parameters inclusive DIS at high Q 2 ✔ some unp. results from HERA 20x250 to 30x325 positron beam ? polarized 3 He beam ? M. Stratmann

Nucleon Spin: Precision measurement of  G 4/12/2011 Abhay Deshpande Overview of the US EIC Project 29 Yellow band (left) reduces to the band shown with red dashed line (right) Yellow band (left) reduces to the band shown with red dashed line (right) Sassot & Stratmann

4/12/2011 Abhay Deshpande Overview of the US EIC Project 30 See more in talks by: T. Ullrich, J. Jalilian-Marian C. Marquet

Nuclear Tomography: (2+1)D images 4/12/2011 Abhay Deshpande Overview of the US EIC Project 31 x < 0.1x ~ 0.3x ~ 0.8 Fourier transform in momentum transfer x ~ EIC: 1) x < 0.1: gluons 1) x < 0.1: gluons! 2)  ~ 0  the “take out” and “put back” gluons act coherently. 2)  ~ 0 x -  x +   d

Diffractive vector meson production in eA 4/12/2011 Abhay Deshpande Overview of the US EIC Project 32  d See T. Ullrich’s talk on eA physics at the EIC Precise transverse imaging of the gluons proton-heavy nuclei Later, how low x dynamics modifies this transverse gluon distribution Exclusive coherent (at small t) and incoherent (intermediate t) Diffraction Experimental challenges being Studied.

EIC Project status and plans A “collaboration” of highly motivated people intends to take this project to realization: – EIC Collaboration Web Page: BNL: JLab: – 100+ dedicated physicists from 20+ institutes – Details of many recent studies: Recent INT at U. of Washington : – Task Force at BNL (E. Aschenaur, T. Ullrich) and at Jefferson Laboratory (R. Ent) – Steering Committee (contact: AD and R. Milner) International Advisory Committee formed by the BNL & Jlab Management to steer this project to realization: W. Henning (ANL, Chair ), J. Bartels (DESY),A. Caldwell (MPI, Munich) A. De Roeck (CERN), R. Gerig (ANL), D. Hetrzog (U of W), X. Ji (Maryland), R. Klanner (Hamburg), A. Mueller (Columbia), S. Nagaitsev (FNAL), N. Saito (J-PARC), Robert Tribble (Texas A&M), U. Wienands (SLAC), V. Shiltev (FNAL) Plan to go to the NSAC Long Range Plan (2012/13) with the science case & machine/detector designs (including costs & realization plans) Plan to go to the NSAC Long Range Plan (2012/13) with the science case & machine/detector designs (including costs & realization plans) 4/12/2011 Abhay Deshpande Overview of the US EIC Project 33

Generic Detector R&D for an EIC Community wide call for R&D Detector proposals for EIC Program run from BNL (RHIC R&D funds), NOT site specific Very Recent: Deadline April 4 th, 2011 (more opportunities in future) New detector technology for fiber sampling calorimetry for EIC and STAR. UCLA, Texas A&M, Penn State Front end readout modules for data acquisition and trigger system. Jefferson Lab DIRC based PID for EIC Central Detector. Catholic U. of America, Old Dominion U., JLab, GSI (Darmstadt) Liquid scintillator calorimeter for the EIC. Ohio State U. Test of improved radiation tolerant silicon PMTs. Jefferson Lab Letter of Intent for detector R&D towards an EIC detector (Low mass tracking and PID ). BNL, Florida Inst. Tech., Iowa State, LBNL, LANL, MIT, RBRC, Stony Brook, U. of Virginia, Yale U. Exploring possible new technologies & attracting new collaborators…. 4/10/11 Abhay Deshpande on EIC Collaboration's Perspective 34

Luminosity upgrade: Further luminosity upgrades (pp, low-E) Staged approach to eRHIC LHC HI starts RHIC-II science by- passing RHIC-II project Opportunity for up- grade* or 1 st EIC stage (eRHIC-I) EIC = Electron- Ion Collider; eRHIC = BNL realization by adding e beam to RHIC Further luminosity upgrades (pp, low-E) eRHIC-I physics * New PHENIX and STAR Decadal Plans provide options for this period. Dedicated storage ring for novel charged-particle EDM measurements another option. © V. Litvinenko eRHIC will add electron ERL inside RHIC tunnel, going from 5 to 30 GeV in stages electron recirc- ulation mag- nets S. Vigdor, BNL Associate Director 35

4/12/2011 Abhay Deshpande Overview of the US EIC Project 36 EIC at JLab Realization Imagined Activity Name Gev Upgrade FRIB EIC Physics Case NSAC LRP CD0 Machine Design/R&D CD1/D’nselect CD2/CD3 Construction H. Montgomery, Jeff. Laboratory Director

Summary Science Case for EIC:  “Precision study of the role of gluons & sea quarks in QCD” Many body dynamics in QCD is an essential focus of this study. Possibilities of precision EW & other physics being explored. The EIC Collaboration & the BNL+Jlab managements are moving ( together ) towards realization: NSAC approval 2013  Next Milestone Machine R&D, detector discussions, simulation studies towards making the final case including cost considerations needs to occur within the next two years… INVITATION: Ample opportunities to get involved and influence the design of this machine according to your own physics interests and participate in the exploration of the “next QCD frontier…”! 4/12/2011 Abhay Deshpande Overview of the US EIC Project 37

Related detailed talks: Reminder… 4/12/2011 Abhay Deshpande Overview of the US EIC Project 38 An update on eRHIC acceleraor V. Litvinenko Design status of of MEIC at JLab V. Morozov PDFs today and tomorrow M. Stratmann Theory overview of e-A physics at the EIC J. Jalilian-Marian Experimental overview of e-A physics at the EIC T. Ullrich A new Monte Carlo event generator for eA collisions at low-x T. Toll Theory overview of e+p physics at an EIC J. Qiu Experimental overview of e+p physics at an EIC H. Gao Imaging sea quarks and gluons at the EIC T. Horn Ep physics opportunities at eRHIC T. Burton Transverse single-spin asymmetry measurement from SIDIS at an EIC M. Huang Weak mixing angle measurement at EIC Y. Li PHENIX and STAR Detector Upgrades (for use as Stage 1 eRHIC detector) E. O’Brien, J. Dunlop … And of course, low-x physics at LHeC is a physics connection

EIC: the Machines, IR and Detector Both BNL and JLab machine designs have progressed significantly. In spite of very different starting points for collider concepts: Both designs are now converging to similar luminosities: – Few x cm -2 sec -1 for high energy – cm -2 sec -1 for low energy Both plan a staged realization Both designs have settled on more than one IR point Both machine designs integrate detector design in to the machine lattice Both detectors concepts include a central solenoid and forward dipole, extensive low mass tracking for low x and good particle ID 4/10/11 Abhay Deshpande on EIC Collaboration's Perspective 40

Measurement of Glue at HERA Scaling violations of F 2 (x,Q 2 ) linear NLO pQCD analyses: fits with linear DGLAP* equations 4/12/2011 Abhay Deshpande Overview of the US EIC Project 41 Gluon dominates * Dokshitzer, Gribov, Lipatov, Altarelli, Parisi

EIC Detector will aim to catch: Wide range in x-Q 2 extremely important to understand longitudinal & transverse spin/momentum distributions and dynamics – Not available at any other existing or future facility with polarized hadron beams being considered… – Lessons learnt from HERA (about measurements at low-x) 4/12/2011 Abhay Deshpande Overview of the US EIC Project 42

Electroweak & beyond High energy collisions of polarized electrons and protons and nuclei afford a unique opportunity to study electro-weak deep inelastic scattering – Electroweak structure functions (including spin) – Significant contributions from W and Z bosons which have different couplings with quarks and anti-quarks Parity violating DIS : a probe of beyond TeV scale physics – Measurements at higher Q 2 than the PV DIS 12 GeV at Jlab – Precision measurement of Sin 2  W New window for physics beyond SM? – Lepton flavor violation search 3/24/11 A. L. Deshpande, Precision study of gluons in QCD 43 arXiv: v1 [hep-ph] M. Gonderinger et al. arXiv: v1 [hep-ph] M. Gonderinger et al. BNL LDRD: Deshpande, Marciano, Kumar & Vogelsang

Some examples of “other” studies initiated…. 4/10/11 Abhay Deshpande on EIC Collaboration's Perspective 44

Some examples of “other” studies initiated…. 4/10/11 Abhay Deshpande on EIC Collaboration's Perspective 45 In part supported by BNL LDRD Write-Ups in the INT Workshop Proceedings

Charged & Neutral Currents… 3/24/11 A. L. Deshpande, Precision study of gluons in QCD × 250 GeV, Q 2 > 1 GeV 2, 0.1 < y < 0.9, 10 fb -1, DSSV PDFs (Could begin the program with 5x250 GeV ) Two studies: (1) Ringer & Vogelsang (these figures), (2) Taneja, Riordin, Deshpande, Kumar & Paschke CC NC

Sin 2  W with the EIC Deviation from the “curve” may be hints of BSM scenarios including: Lepto-Quarks, RPV SUSY extensions, E 6 /Z’ based extensions of the SM 3/24/11 A. L. Deshpande, Precision study of gluons in QCD 47 Y. Li, W. Marciano

Opportunity for EIC LFV(1,3) Limits on LFV(1,3) experimental searches are significantly worse than those for LFV(1,2) Especially if there are BSM models which specifically allow and enhance LFV(1,3) over LFV(1,2) – Minimal Super-symmetric Seesaw model J. Ellis et al. Phys. Rev. D (2002) – SU(5) GUT with leptoquarks I. Dorsner et al., Nucl. Phys. B (2005) P. Fileviez Perez et al., Nucl. Phys. B (2009) M. Gonderinger & M.Ramsey Musolf, JHEP 1011 (045) (2010); arXive: [hep-ph] Clearly there is an opportunity for EIC: if a search can be effectively launched with it’s planned (high luminosity) and large large acceptance detector suitable for the GPD/Exclusive physics program 3/24/11 48 A. L. Deshpande, Precision study of gluons in QCD

How does this compare with HERA? Private communications: M. Gonderinger 3/24/11 A. L. Deshpande, Precision study of gluons in QCD 49

SM vs. LPQ Comparisons  miss –  jet = Acoplanarity Very different for SM vs. LPQ 3/24/11 A. L. Deshpande, Precision study of gluons in QCD 50 C. Faroughy, S. Taneja, M. Gonderinger, A. Deshpande & K. Kumar Pythia for Standard Model event topologies LQGENEP Event generator for Lepto-Quark events. By L. Bellagamba Comp. Phys. Comm. 141, 83 (2001)

SM vs. LPQ P t miss 10 x x 325 3/24/11 A. L. Deshpande, Precision study of gluons in QCD 51

Acoplanarity:  miss -  jet 10 x x 325 3/24/11 A. L. Deshpande, Precision study of gluons in QCD 52

To do: Inclusion of detector efficiencies A detailed study of efficiency of cuts/selection criteria and its efficiency. Only then can we calculate the effective sensitivity per event not seen A GEANT based simulation of the detector is needed… and being planned. 4/12/2011 Abhay Deshpande Overview of the US EIC Project 53