Thomas Jefferson National Accelerator Facility
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SPIN2006, October 7, 2006, 1
Future Spin Physics at JLabFuture Spin Physics at JLab
12 GeV and Beyond12 GeV and Beyond
Kees de Jager
Jefferson Lab
SPIN2006
Kyoto
October 2-7, 2006
Thomas Jefferson National Accelerator Facility
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SPIN2006, October 7, 2006, 2
Highlights of the 12 GeV Program
• Revolutionize Our Knowledge of Spin and Flavor Dependence of PDFS in the Valence Region
• Strongly Enhance Our Knowledge of Distribution of Charge and Current in the Nucleon
• Totally New View of Hadron (and Nuclear) Structure: GPDs Determination of the quark angular momentum
• Exploration of QCD in the Nonperturbative Regime: Existence and properties of QCD flux-tube excitations
• New Paradigm for Nuclear Physics: Nuclear Structure in Terms of QCD Spin and flavor dependent EMC Effect Study quark propagation through nuclear matter
• Precision Tests of the Standard Model Factor 20 improvement in (2C2u-C2d) electron-quark couplings
Determination of sin2w to within 0.00025
Thomas Jefferson National Accelerator Facility
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SPIN2006, October 7, 2006, 3
Examples of the 12 GeV Upgrade Research
• Parton Distribution Functions
• Form Factors
• Generalized Parton Distributions
• Exotic Meson Spectroscopy: Confinement and the QCD vacuum
• Nuclei at the level of quarks and gluons
• Tests of Physics Beyond the Standard Model
Thomas Jefferson National Accelerator Facility
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Hall A at 11 GeV with BigBite
12 GeV : Unambiguous Flavor Structure x —> 1After 35 years: Miserable Lack of Knowledge of Valence d-Quarks
di-quarkcorrelations
pQCD
Thomas Jefferson National Accelerator Facility
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A1p at 11 GeV
Unambiguous Resolution of Valence Spin
A1n at 11 GeV
Thomas Jefferson National Accelerator Facility
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At RHIC with W productionAt JLab with 12 GeV upgrade
Stops at x≈0.5 AND needs valence d(x)
Complements Spin-Flavor Dependence at RHIC
12
Thomas Jefferson National Accelerator Facility
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• Parton Distribution Functions
• Form Factors
• Generalized Parton Distributions
• Exotic Meson Spectroscopy: Confinement and the QCD vacuum
• Nuclei at the level of quarks and gluons
• Tests of Physics Beyond the Standard Model
Examples of the 12 GeV Upgrade Research
Thomas Jefferson National Accelerator Facility
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SPIN2006, October 7, 2006, 8
Proton Neutron
Electric
Magnetic
Experiments at 11 GeV will extend data
To 5 GeV2
To 15 GeV2
To 14 GeV2
Thomas Jefferson National Accelerator Facility
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SPIN2006, October 7, 2006, 9
Examples of the 12 GeV Upgrade Research
• Parton Distribution Functions
• Form Factors
• Generalized Parton Distributions
• Exotic Meson Spectroscopy: Confinement and the QCD vacuum
• Nuclei at the level of quarks and gluons
• Tests of Physics Beyond the Standard Model
Thomas Jefferson National Accelerator Facility
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SPIN2006, October 7, 2006, 10
The Next Generation of Proton Structure Experiments
Elastic Scattering
transverse quark distribution in
Coordinate space
DISlongitudinal
quark distributionin momentum space
GPDsThe fully-correlated
Quark distribution in both coordinate and
momentum space
Thomas Jefferson National Accelerator Facility
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SPIN2006, October 7, 2006, 11
Generalized Parton Distributions (GPDs): New Insight into Hadron Structure
JG = 1
1
)0,,()0,,(21
21 xExHxdxJ qqq
Quark angular momentum (Ji’s sum rule)
X. Ji, Phy.Rev.Lett.78,610(1997)
e.g.
Flavor separationthrough Deeply Virtual Meson Production
Thomas Jefferson National Accelerator Facility
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Access GPDs through x-section and asymmetries
Accessed by cross sections
Accessed by beam/target spin asymmetry
t = 0
Quark distribution q(x)
-q(-x)
DIS measures at =0
Flavor separationthrough DVMP
Thomas Jefferson National Accelerator Facility
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Exclusive 0 with transverse target
Asymmetry depends linearly on the GPD E, which enters Ji’s sum rule
A ~ (2Hu +Hd)B ~ (2Eu + Ed)
L dominance Q2 =1
-t = 0.5GeV2 t = 0.2
L=1035cm-2s-1
2000hrs
AUT
K. Goeke, M.V. Polyakov, M. Vanderhaeghen, 2001
xB
AUT =−2⊥ Im(AB* ){ } / π
A 2 1−2( )−B 2 2 + t / 4m2( )−Re AB*( )22
Thomas Jefferson National Accelerator Facility
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SPIN2006, October 7, 2006, 14
Examples of the 12 GeV Upgrade Research
• Parton Distribution Functions
• Form Factors
• Generalized Parton Distributions
• Exotic Meson Spectroscopy: Confinement and the QCD vacuum
• Nuclei at the level of quarks and gluons
• Tests of Physics Beyond the Standard Model
Thomas Jefferson National Accelerator Facility
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SPIN2006, October 7, 2006, 15
Gluonic Excitations and the Origin of ConfinementConfinement is due to the formation of “Flux tubes” arising from the self-interaction of the glue, leading to a linear confining potential
Experimentally, we want to “pluck” the flux tube and see how it responds
π/rground statetransverse phonon modes Hybrid mesons
Normal mesons
~1 GeV mass difference
Jpc = 1-+
An excited flux tube gives rise to hybrid mesons with conventional and exotic quantum numbers JPC
Thomas Jefferson National Accelerator Facility
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Glueballs and hybrid mesons
Colin Morningstar:Gluonic Excitations workshop, 2003 (JLab)
Thomas Jefferson National Accelerator Facility
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Physics goals and key features
The physics goal of GlueX is to map the spectrum of hybrid mesons in a mass range 1.5 to 2.5 GeV, starting with those with the unique signature of exotic JPC
Identifying JPC requires an amplitude analysis which in turn requires
linearly polarized photons detector with excellent acceptance and resolution sensitivity to a wide variety of decay modes
In addition, sensitivity to hybrid masses up to 2.5 GeV requires 9 GeV photons which will be produced using coherent bremsstrahlung from 12 GeV electrons
Final states include photons and charged particles and require particle identification
Hermetic detector with large acceptance for charged and neutral particles
Thomas Jefferson National Accelerator Facility
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SPIN2006, October 7, 2006, 18
Examples of the 12 GeV Upgrade Research
• Parton Distribution Functions
• Form Factors
• Generalized Parton Distributions
• Exotic Meson Spectroscopy: Confinement and the QCD vacuum
• Nuclei at the level of quarks and gluons
• Tests of Physics Beyond the Standard Model
Thomas Jefferson National Accelerator Facility
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SPIN2006, October 7, 2006, 19
• Observation stunned and electrified the
HEP and Nuclear communities 20 years ago• Nearly 1,000 papers have been generated…..• What is it that alters the quark momentum in the nucleus?
Classic Illustration: The EMC effect
J. Ashman et al., Z. Phys. C57, 211 (1993)
J. Gomez et al., Phys. Rev. D49, 4348 (1994)
The EMC Effect: Nuclear PDFs
Thomas Jefferson National Accelerator Facility
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Unpacking the EMC effect
• With 12 GeV, we have a variety of tools to unravel the EMC effect: Parton model ideas are valid over fairly wide kinematic
range High luminosity High polarization
• New experiments, including several major programs: Precision study of A-dependence; x>1; valence vs. sea g1A(x) “Polarized EMC effect” – influence of nucleus on
spin Flavor-tagged polarized structure functions uA(xA) and
dA(xA) x dependence of axial-vector current in nuclei (can study
via parity violation) Nucleon-tagged structure functions from 2H and 3He Study x-dependence of exclusive channels on light nuclei,
sum up to EMC
Thomas Jefferson National Accelerator Facility
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SPIN2006, October 7, 2006, 21
Examples of the 12 GeV Upgrade Research
• Parton Distribution Functions
• Form Factors
• Generalized Parton Distributions
• Exotic Meson Spectroscopy: Confinement and the QCD vacuum
• Nuclei at the level of quarks and gluons
• Tests of Physics Beyond the Standard Model
Thomas Jefferson National Accelerator Facility
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PV DIS at 11 GeV with an LD2 target
• 6 GeV experiment will launche PV DIS measurements at JLab• 11 GeV experiment requires tight control of normalization errors• Important constraint should LHC see anomaly
€
APV =GFQ2
2παa(x) + f (y)b(x)[ ]
€
a(x) =
C1iQi f i(x)i
∑
Qi2 f i(x)
i
∑
€
y ≡1− ′ E / E
€
b(x) =
C2iQi f i(x)i
∑
Qi2 f i(x)
i
∑
e-
N X
e-
Z* *
For an isoscalar target like 2H, structure functions largely cancel in the ratio:
€
a(x) =3
10(2C1u − C1d )[ ] +L
€
b(x) =3
10(2C2u − C2d )
uv (x) + dv (x)
u(x) + d(x)
⎡
⎣ ⎢ ⎤
⎦ ⎥+L
(Q2 >> 1 GeV2 , W2 >> 4 GeV2, x ~ 0.3-0.5)
• Must measure APV to 0.5% fractional accuracy• Luminosity and beam quality available at JLab
Thomas Jefferson National Accelerator Facility
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1% APV
measurements
Precision High-x Physics with PV DIS
Charge Symmetry Violation (CSV) at High x: clean observation possible
€
δu(x) = up (x) − dn (x)
δd(x) = d p (x) − un (x)
€
δAPV (x)
APV (x)= 0.3
δu(x) −δd(x)
u(x) + d(x)
Global fits allow 3 times larger effects
€
APV =GFQ2
2παa(x) + f (y)b(x)[ ]
€
a(x) =u(x) + 0.91d(x)
u(x) + 0.25d(x)
• Allows d/u measurement on a single proton!
Longstanding issue: d/u as x1
For hydrogen 1H:
Londergan & Thomas
• Direct observation of CSV at parton-level • Implications for high-energy collider pdfs• Could explain large portion of the NuTeV
anomalyNeed 1% APV measurement at x ~ 0.75
Thomas Jefferson National Accelerator Facility
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• Comparable to single Z pole measurement: shed light on disagreement
• Best low energy measurement until ILC or -Factory • Could be launched ~ 2015
Future Possibilities (Purely Leptonic)-e in reactor can test neutrino coupling: sin2W to ± 0.002
Møller at 11 GeV at Jlab sin2W to ± 0.00025!ee ~ 25 TeV reach!Higher luminosity and acceptance
JLab e2e @ 12 GeV
e.g. Z’ reach ~ 2.5 TeV
Does Supersymmetry (SUSY) provide a candidate for dark matter?•Neutralino is stable if baryon (B) and lepton (L) numbers are conserved•B and L need not be conserved (RPV): neutralino decay
Thomas Jefferson National Accelerator Facility
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CHL-2CHL-2
Upgrade magnets Upgrade magnets and power and power suppliessupplies
Enhance equipment in Enhance equipment in existing hallsexisting halls
6 GeV CEBAF1112Add new hallAdd new hall
Thomas Jefferson National Accelerator Facility
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HALL A - 12 GeV Upgrade Summary
Infrastructure for
Large Installations
Thomas Jefferson National Accelerator Facility
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A Vision for Precision PV DIS Physics
• Hydrogen and Deuterium targets• Better than 2% errors
It is unlikely that any effects are larger than 10%
• x-range 0.25-0.75• W2 well over 4 GeV2
• Q2 range a factor of 2 for each x
(Except x~0.75)• Moderate running times
• CW 90 µA at 11 GeV• 40 cm liquid H2 and D2 targets• Luminosity > 1038/cm2/s
• solid angle > 200 msr• count at 100 kHz• on-line pion rejection of 102 to 103
Goal: Form a collaboration, start real design and simulations, and make pitch to US community at the next nuclear physics Long Range Plan (2007)
Thomas Jefferson National Accelerator Facility
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Beamline Instrumentation
Preshower Calorimeter
Forward Drift Chambers
Inner Cerenkov(HTCC)
SuperconductingTorus Magnet
Central Detector
Forward Calorimeter
Forward Time-of-Flight
Detectors
* Reused detectors from CLAS
Forward Cerenkov(LTCC)
Inner Calorimeter
Hall B - CLAS12
New TOF Layer
Thomas Jefferson National Accelerator Facility
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Hall C - Side View of SHMS Design
Thomas Jefferson National Accelerator Facility
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Argon/Neon Cerenkov
HGCS1XS1Y
AGCDC1 DC2
TRD S2X S2Y LGCA1
C4F10 Cerenkov
ElevationS2Y
SHMS/HMS: Detector Systems
Option: Replace Cherenkov with Focal Plane Polarimeter
(for π/e at high E’ only, otherwise vacuum)
Space for aerogel, etc.
Quartz Hodoscope
Thomas Jefferson National Accelerator Facility
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SHMS/HMS: Detector Systems
Option: Replace Cherenkov with Focal Plane Polarimeter,with a similar option in SHMS!
Argon/Neon Cerenkov
AGC
DC1 DC2 LGC
FPP FPP
S1XS1YS2X S2Y LGC
(Q2 > 12 GeV2)
(for π/e at high E’ only, otherwise vacuum)
Thomas Jefferson National Accelerator Facility
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flu
x
photon energy (GeV)
12 GeV electron beam
This technique provides requisite energy, flux and
linear polarization
collimated
Incoherent &coherent spectrum
tagged(0.1% resolution)
40%polarization
in peak
electrons in
photons out
spectrometer(two magnets)
diamondcrystal
Hall D - Coherent Bremsstrahlung
Thomas Jefferson National Accelerator Facility
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Tagger Spectrometer(Upstream)
Hermetic detectionof charged and neutral particles
Hall D - GluEx Detector
Thomas Jefferson National Accelerator Facility
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12 GeV Upgrade: Project Schedule
• 2004-2005 Conceptual Design (CDR)• 2004-2008 Research and Development
(R&D)• 2006 Advanced Conceptual Design (ACD)• 2007-2009 Project Engineering & Design
(PED)• 2008-2009 Long Lead Procurement• 2009-2013 Construction• 2012-2014 Pre-Ops (beam commissioning)
Critical Decision (CD) Presented at IPR
CD-0 Mission Need 2QFY04 (Actual)
CD-1 Preliminary Baseline Range 2QFY06 (Actual)
CD-2A/3A Construction and Performance Baseline of Long Lead Items
4QFY07
CD-2B Performance Baseline 4QFY08
CD-3B Start of Construction 2QFY09
CD-4 Start of Operations 1QFY15
• JLab Upgrade only present construction project in DOE-NP
• First 12 GeV beam expected in ~2012
• However, plans for next upgrade already being developed now
Thomas Jefferson National Accelerator Facility
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Why Electron-Ion Collider?
• Polarized DIS and e-A physics: in past only in fixed-target mode• Collider geometry allows complete reconstruction of final state• Better angular resolution between beam and target fragments
• Lepton probe provides precision but requires high luminosity to be effective
• High Ecm large range of x, Q2 Qmax2= ECM
2•x
x range: valence, sea quarks, glueQ2 range: utilize evolution equations of QCD
• High polarization of lepton and nucleon a requisite
Thomas Jefferson National Accelerator Facility
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Ring-Ring Concept
• Use present CEBAF as injector to electron storage ring
• Add light-ion complex
Linac 200 MeV
Ion Collider Ring
Pre-Booster3 GeV/c
C≈75-100 m
Ion Large Booster 20 GeV
(Electron Storage Ring)
spin
Thomas Jefferson National Accelerator Facility
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Achieving the Luminosity of ELIC
For 150 GeV protons on 7 GeV electrons, L~ 8 x 1034 cm-2 s-1 is compatible with realistic Interaction Region design.
Beam Physics Issues
• High energy electron cooling
• Beam – beam interaction between electron and ion beams
(i ~ 0.01 per IP; 0.025 is presently utilized in Tevatron)
• Interaction Region
High bunch collision frequency (f = 1.5 GHz)
Short ion bunches (z ~ 5 mm)
Very strong focus (* ~ 5 mm)
Crab crossing
*24i e
b
N NL f
π=
Thomas Jefferson National Accelerator Facility
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Polarization of Electrons/Positrons
• Spin injected vertical in arcs (using Wien filter) • Self-polarization in arcs to support injected polarization • Spin rotators matched with the cross bends of Interaction Points• Electrons at 200 MeV yield unpolarized positron accumulation of ~100
mA/min• ½ hr to accumulate 3 A of positron current• Sokolov-Ternov polarization for positrons (2 hrs at 7 GeV – varies as E-5)
spin rotator
spin rotator
spin rotator
spin rotator
collision point
spin rotator with 90º
solenoid snake
collision point
collision point
collision point
spin rotator with 90º
solenoid snake
Thomas Jefferson National Accelerator Facility
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Summary of Future Spin Physics at JLab
• The Upgrade to 12 GeV at JLab is well underway (preparing for CD-2 review)
• It will allow ground-breaking studies of
the structure of the nucleon
exotic mesons and the origin of confinement
the QCD basis of nuclear structure
the Standard Model at the multi-TeV scale
All requiring the use of highly polarized beams (and/or targets)
• The schedule of LQCD calculations at JLab is commensurate with the physics goals of the 12 GeV Upgrade
• Design studies at JLab have led to a promising design of an electron-ion collider
a luminosity of up to ~1035 cm-2 s-1
at a center-of-mass energy between 20 and 65 GeV
for collisions between polarized electrons/positrons and light ions (A≤40)