Transcript 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.

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 GeV on 25-250 GeV ep/eA collider
 fully-polarized, longitudinal and transverse
 JLab implementation: luminosity ~7x 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 GeV is expensive
Electron
Cooling
ELIC
IR
Snake
New Ion Complex:
30-250 GeV Protons
15 -125 GeV/n Ions
IR
Snake
CEBAF:
3-11 GeV
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 GeV 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 the
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 LRP07):
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 3D 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 = Mc2 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 Q2 > 10
- any QCD machine needs range in Q2
 s = 1000 or so to reach decade in Q2
 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 GeV (minimize synchrotron)
- proton energies ranging from 30 to 60 GeV
- but larger range of s accessible (Ee = 11 GeV, Ep = 12 GeV)
• 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-GeV 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 GeV
• proton energies ranging from 12 to 60 GeV
• 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 GeV
• Consistent with NSAC Long-Range Plan
2009: A High-Luminosity Medium-Energy Collider
(MEIC) for Nuclear Physics at Jlab






MEIC
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 GeV Protons
15 -30 GeV/n Ions
CEBAF:
3-11 GeV
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
(~600m)
ELIC
Footprint
(~1800m)
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-Q2 “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 eA diffraction?, etc.)
(M)EIC@JLab Interaction Region Concept
IR1: General Purpose detector
(but not diffractive/low-Q2?)
IR3: Diffractive/Low-Q2 detector
Medium
Energy IP
Snake
Insertion
60°
p
Low
Energy IP
e
IR2: Polarimetry etc.
IR Regions:
+/- 9 meter
IR4: 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-GeV 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!
- Ecm2 = s = 4E1E2 for colliders, vs. s = 2ME for fixed-target
 4 GeV electrons on 12 GeV protons ~ 100 GeV fixed-target
- Easier to produce many J/Y’s, high-pT pairs, etc.
- Easier to establish good beam quality in collider mode
Longitudinal polarization FOM
Target
p
d
fdilution,
Pfixed_target
f2P2fixed_target
f2P2EIC
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 @ Q2 > 10 GeV2
 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/Q2 (Mott) x
1/Q4 (hard gluon exchange)2
s
L
Q2 reach
DVCS
Q2 reach
(e,e’p)
12-GeV
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 (GeV)
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,
1H, 2H, 3He,
heavy A,
low, high Ecm
sin2θW
100
∫L dt (fb-1)
(M)EIC@JLab: Where
we
are
(or, were for 8 m detector space)
Luminosity (1033 s-1 cm-2)
Polarized ep Facilities
JLab/12
HERMES
ENC/GSI
COMPASS
1)
2)
3)
(M)EIC
4)
Staged eRHIC
s (GeV2)
Plot assumptions:
(M)EIC Luminosities
optimized at 5 GeV on 12
GeV and 5 GeV on 60 GeV.
Detector/DAQ/electronics
limits the luminosity to 1035.
Scale to higher electron
beam energies (up to 11 GeV)
at fixed synchrotron limit.
Luminosity for staged eRHIC
at 2 on 250 is similar as for
4 GeV on 250 GeV.
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 @ Q2 = 1)
(x = 0.01 @ Q2 = 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(Q2), 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 F326/7
All meetings can be accessed by all, also remotely.
(1st meeting is call-in, 2nd meeting is EVO video conferencing)
If interested, please subscribe to [email protected]
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 ~ Q2/ys
1035
EW
1034
DES
SIDIS
1033
DIS
1032
10
DIFF
100
1000
10000
s (GeV2)
Saturation
100000
CTEQ Example at Scale Q2 = 10 GeV2
“dip” in u,d pdf’s at x ~
0.01 (@ Q2 =10 GeV2)
 s ~ 1000 appropriate
The Venerable (Nuclear) EMC Effect
F2A/F2D
10-4
“EMC Effect”
10-3
10-2
Space-Time Structure of Photon
10-1
x
1
x < (5 times 10-3) for saturation in
shadowing to start? Need about
decade in Q2 to verify LT vs. HT
of effects  want to push down
to x ~ 0.0005 (@ Q2 = 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
sEIC/sHERA
boost in
“virtual” x reach
gluon density boost over HERA
over HERA at Q2 = 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 ~ A1/3 x s0.3
(A = 208)
Four Electron-Ion Collider Facilities Considered
eRHIC
ELIC Electron
e-cooling
(RHIC II)
Cooling
IR
PHENIX
IR
Main ERL (2 GeV per pass)
Snake
STAR
MANUEL
Add electron
beam (COSY ring)
to GSI/HESR
Four e-beam
passes
LHeC
Snake
Four Electron-Ion Collider Facilities Considered
EICx2: L > 1x1033 cm-2s-1
Ecm = 20-100+ GeV
LHeC: L = 1.1x1033 cm-2s-1
Ecm = 1.4 TeV
• Variable energy range
• Polarized and heavy ion beams
• High luminosity in energy region
• Add 70-100 GeV electron ring to
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.
High-Energy physics goals:
• Parton dynamics at the TeV scale
- physics beyond the
Standard Model
- physics of high parton
densities (low x)
of interest for nuclear science
MANUEL@FAIR:
L > 1x1033 cm-2s-1?
Ecm = 13 GeV
interact with LHC ion beam
• Use LHC-B interaction region
• High luminosity mainly due to
large g’s (= E/m) of beams
• Add 3 GeV 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
WM
City of NN
Symantac
State
City of NN
SURA
Recent Progress with a High-Luminosity EIC at JLab
• 2007 LRP: EIC = a 3-10 GeV on 25-250 GeV ep/eA 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.”