EIC NAS review Charge-2 What are the capabilities of other facilities, existing and planned, domestic and abroad, to address the science opportunities afforded by an electron-ion collider? What unique scientific role could be played by a domestic electron ion collider facility that is complementary to existing and planned facilities at home and elsewhere?

Slides for Charge-2 These slides were culled from material gathered by EIC UG on Charge-2 for the NAS Committee. The following slides are meant to be complimentary to the material presented by various speakers at the NAS Apr. 19 open meeting. Composition of the slides: Slides 4 & 5: Summary: why polarization, large kinematic coverage, and high luminosity are critical for EIC. Slides 6-8: Main EIC science aims and the role of other facilities existing and planned on those aims. Slides 7 & 8: Areas where EIC can contribute significantly to the main science aims of other facilities. June, 2017 Input to NAS committee

Why Polarization, large kinematic coverage , and Luminosity are critical non-linear dynamic Regime QCD radiation dominated Regime Many-body Regime Few-body/ valence quark Regime x (proton) 10-5 10-4 10-3 10-2 10-1 1 ? large kinematic coverage: access to x and Q2 over a wide range  from large to small x polarized electron and hadron beams: access to spin structure of nucleons and nuclei Spin vehicle to access the spatial and momentum structure of the nucleon in 3d Full specification of initial and final states to probe q-g structure of NN and NNN interaction in light nuclei nuclear beams: accessing the highest gluon densities high luminosity: mapping the spatial and momentum structure of nucleons and nuclei in 3d access to rare probes June, 2017 Input to NAS committee

Why is large kinematic coverage critical: Q2 EIC ideal to probe transition from non-perturbative to perturbative regime connect measurements already existing in different regimes Non-perturbative Regime Perturbative Regime Transition Region EIC RHIC LHC HERMES, COMPASS, JLAB 6 and 12 Q2 HERA high-x 103 104 [GeV2] 10-1 1 10 102 Q2 (GeV2) Probing momentum Asymptotic freedom 2 GeV (1/10) fm) 200 MeV (1 fm) Color Confinement June, 2017 Input to NAS committee

Quark and Gluon Structure in 3D EIC Science Goal How are the sea quarks and gluons, and their spins, distributed in space and momentum inside the nucleon? How do the nucleon properties emerge from them and their interactions? Complementary measurements at other facilities. JLAB 12, COMPASS, HIAF-EIC: Measure at high x and lower Q2 (1D & 3D) LHeC, VHEeP, FCC-eh: Measure at lower x (mainly 1D) LHC, HL-LHC, RHIC; Ultra-peripheral collisions. mostly low Q2~0, but high energy (1D & 3D) Parton distributions using q-q, q-g or g-g interactions (mainly 1D) comment emphasis spin more Other facilities are limited either in kinematic coverage, polarization or 3D measurement capability. They will be able to extend EIC data in certain kinematic regions. HIAF-EIC, LHeC, VHEeP, FCC-eh: Facility concepts June, 2017 Input to NAS committee

Propagation of Color in Cold QCD and Emergence of Hadrons EIC Science Goal How do color-charged quarks and gluons, and colorless jets, interact with a nuclear medium? How do the confined hadronic states emerge from these quarks and gluons? How do the quark-gluon interactions create nuclear binding? Complementary measurements at other facilities. LHC, HL-LHC, RHIC: propagation of color in hot and cold QCD FRIB, ATLAS, FAIR, HIAF and other nuclear structure facilities: Nuclear structure data complements and informs EIC measurements. The EIC science will build a bridge between hot and cold QCD as well as between low energy nuclear structure and quark-gluon structure of nuclei. June, 2017 Input to NAS committee

QCD at Extremes How does a dense nuclear environment affect the quarks and gluons, their correlations, and their interactions? What happens to the gluon density in nuclei? Does it saturate at high energy, giving rise to a gluonic matter with universal properties in all nuclei, even the proton? gluon emission gluon recombination ?=? EIC Physics Goal Complementary measurements at other facilities. LHC, HL-LHC, RHIC: study saturation in pA collisions: UPC, di-hadron correlations, open charm at forward rapidities (lower x)  universality Effects of saturation on ion-ion collisions. LHeC, VHEeP, FCC-eh: Access lower x. EIC studies the transition between a non-saturated and saturated regime with high precision, by making use of a large range of nuclei and spin LHeC, VHEeP, FCC-eh: Facility concepts June, 2017 Input to NAS committee

Physics Beyond the Standard Model Discovery of BSM physics at LHC (or any other energy frontier machine, e.g. FCC, or SppC) means looking for: σSM(PDF(hadron 1), PDF(hadron 2)) ≠ σmeasured The mass reach of the search becomes higher as x1 for the PDFs. Uncertainty in the knowledge of Parton Distribution Functions (PDFs) limits the reach of the search. LHC (or any other similar machine) cannot disentangle PDFs from new physics using its own measurements. Complementary measurements at EIC: EIC will measure PDFs at high-x, moderate-√s (where it is known that physics obeys SM). This will calibrate high-√s high-mass searches at LHC EIC has the potential to considerably extend the discovery reach of the LHC, HL-LHC and other frontier energy machines with a precise measurement of PDFs at high-x. June, 2017 Input to NAS committee

Quark-Gluon Plasma Initial State time Our understanding of fundamental properties of the Glasma, sQGP and Hadron Gas depend on our knowledge of the initial state! Collective phenomena seen in AA, pA, pp collisions  consequence of initial state? EIC: Precision map of quark and gluon structure in 3D June, 2017 Input to NAS committee