1. 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?

2. 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 complementary to the material presented by various speakers at the NAS Apr. 19 open meeting.
Composition of the slides:
Slides 3 & 4: Summary: why polarization, large kinematic coverage, and high luminosity are critical for EIC.
Slide 5: shows the US-EIC in comparison to other existing and planned ep facilities in the world
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.

3. 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

4. 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
10-1 1 10
102
103
104
[GeV2]
Q2 (GeV2)
Probing
momentum
Asymptotic freedom
2 GeV (1/10) fm)
200 MeV (1 fm)
Color Confinement

5. Uniqueness of EIC amongst all DIS facilities
BCDMS
MESA
PERLE
JLab 6 & 12
SLAC
COMPASS
HERMES
NMC
HERA
LHeC
FCC-eh
CEIC
0.1 1 10
100
1000
10000
1030
1032
1034
1036
1038
1040
US EIC Realization
Plans
CMS Energy [GeV]
Luminosity (cm-2 sec-1)
FIXED TARGET
HERA and CERN
EIC Projects
US-EIC:
Spin, ion species together with its luminosity and √s coverage makes it a completely unique machine.

6. 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 (predominately 1D&3D)
LHC, HL-LHC, RHIC;
Ultra-peripheral collisions (UPC) 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, particle ID
or 3D measurement capability.
They will be able to extend EIC data in certain kinematic regions.
HIAF-EIC, LHeC, VHEeP, FCC-eh: Facility concepts

7. 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.

8. 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

9. 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.

10. 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. Precision measurement of Nuclear PDF