Thomas Jefferson National Accelerator Facility
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INPC2007, June 6, 2007, 1
Future Research at Jefferson LabFuture Research at Jefferson Lab
12 GeV and Beyond12 GeV and BeyondKees de Jager
Jefferson Lab
INPC2007Tokyo
June 3-8, 2007
Thomas Jefferson National Accelerator Facility
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INPC2007, June 6, 2007, 2
•~1200 active users worldwide engaged in exploring and understanding the quark-gluon structure of matter
A C
•The SRF electron accelerator provides CW beams of unprecedented quality (polarization of up to 85%) with a maximum beam energy of 6 GeV
•CEBAF’s innovative design allows delivery of beam with unique properties to three experimental halls simultaneously
•Each of the three halls offers complementary experimental capabilities and allows for large equipment installations
B
Jefferson Lab Today
Thomas Jefferson National Accelerator Facility
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Highlights of the 12 GeV Program• Revolutionize Our Knowledge of Spin and Flavor Dependence of
PDFS in the Valence Region • 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 Quark propagation through nuclear matter
• Precision Tests of the Standard Model Factor 20 improvement in (2C2u-C2d) axial-vector quark couplings Determination of sin2w to within 0.00025
Thomas Jefferson National Accelerator Facility
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Examples of the 12 GeV Upgrade Research•Parton Distribution Functions
•Generalized Parton Distributions and Form Factors
•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 SpinA1
n 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
• Generalized Parton Distributions and Form Factors
•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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INPC2007, June 6, 2007, 9
Generalized Parton Distributions (GPDs)
Proton form factors, transverse charge & current densities
Structure functions,quark longitudinalmomentum & helicity distributions
X. Ji, D. Mueller, A. Radyushkin (1994-1997)
Correlated quark momentum and helicity distributions in transverse space - GPDs
Thomas Jefferson National Accelerator Facility
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What’s the use of GPDs?
2. Allows for Transverse Imaging
3. Allows access to quark angular momentum
1. Allows for a unified description of form factors and parton distributions
gives transverse size of quark (parton) with longitud. momentum fraction x
Fourier transform in momentum transfer
x < 0.1 x ~ 0.3 x ~ 0.8
Thomas Jefferson National Accelerator Facility
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Generalized Parton Distributions (GPDs):
e.g.
Flavor separationthrough Deeply Virtual Meson Production
Quark angular momentum (Ji’s sum rule)
X. Ji, Phy.Rev.Lett.78,610(1997)
J q =12−JG =
12
xdx−1
1
∫ H (x,x,0)+ E(x,x,0)⎡⎣ ⎤⎦
hard vertices
Deeply Virtual Compton Scattering (DVCS)
“handbag” mechanism
x – quark momentum fraction
x – longitudinal momentum transfer
√–t – Fourier conjugate to transverse impact parameter
Thomas Jefferson National Accelerator Facility
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Exclusive 0 production on transverse target
Asymmetry depends linearlyon the GPD E, which enters Ji’s sum rule
A ~ 2Hu + Hd
B ~ 2Eu + Ed0
K. Goeke, M.V. Polyakov,M. Vanderhaeghen, 2001
A ~ Hu - Hd B ~ Eu - Ed+
AUT
xB
0
AUT =−2Δ⊥[Im (AB*)] / p
A2 (1−x2 )− B 2 (x2 + t / 4m 2 )−Re(AB*)2x2
Thomas Jefferson National Accelerator Facility
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Proton Neutron
Electric
Magnetic
Experiments at 11 GeV will extend EMFF data
To 5 GeV2
To 15 GeV2
To 15 GeV2
Thomas Jefferson National Accelerator Facility
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INPC2007, June 6, 2007, 14
Examples of the 12 GeV Upgrade Research
• Parton Distribution Functions
• Generalized Parton Distributions and Form Factors
• 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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Flux Tubes and Confinement
Color Field: Because of self interaction, confining flux tubes form between static color chargesNotion of flux tubes comes about from model-independent
general considerations. Idea originated with Nambu in the ‘70s
Thomas Jefferson National Accelerator Facility
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π/rground statetransverse phonon modes Hybrid mesons
Normal mesons
1 GeV mass difference
Hybrid mesons and mass predictions
Lattice 1-+ 1.9 GeV2+- 2.1 GeV0+- 2.3 GeV
Lowest mass expected to be p1(1−+) at 1.9±0.2 GeV
Jpc = 1-+
Thomas Jefferson National Accelerator Facility
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Why Photoproduction ?
A pion or kaon beam, when scattering occurs,
can have its flux tube excitedpbeam
Quark spins anti-aligned
Much data in hand but littleevidence for gluonic excitations
(and not expected)
q
q
befo
req
qaf
ter
q
q
afte
r
q
q
befo
rebeam
Almost no data in hand in the mass region
where we expect to find exotic hybridswhen flux tube is excited
Quark spins aligned
Jpc = 1-+
Thomas Jefferson National Accelerator Facility
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Physics goals and key featuresThe physics goal of GlueX is to map the spectrum of hybrid mesons 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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Examples of the 12 GeV Upgrade Research
• Parton Distribution Functions
• Generalized Parton Distributions and Form Factors
• 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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• 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 ΔuA(xA) and ΔdA(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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Examples of the 12 GeV Upgrade Research
• Parton Distribution Functions
•Generalized Parton Distributions and Form Factors
• 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 launch PV DIS measurements at JLab (2009)
• 11 GeV experiment will allow tight control of systematic errors• Important constraint should LHC observe an 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) =C2 iQi f i(x)
i∑
Qi2 f i(x)
i∑
e-
N X
e-
Z* *
For an isoscalar target like 2H, the structure functions largely cancel in the ratio:
€
a(x) = 310
(2C1u − C1d )[ ] +L
€
b(x) = 310
(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 DISCharge Symmetry Violation (CSV) at High x: clean observation possible?
€
du(x) = up (x) − dn (x)
δd(x) = d p (x) − un (x)
€
dAPV (x)APV (x)
= 0.3δu(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 x1For hydrogen 1H:
Londergan & Thomas
• Direct observation of CSV at parton level!• Implications for high-energy collider pdfs• Could explain large portion of the NuTeV
anomalyNeeds 1% measurement of APV at x ~ 0.75
Thomas Jefferson National Accelerator Facility
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A Vision for Precision PV DIS Physics
• Hydrogen and Deuterium targets• Better than 2% errors
(unlikely that any effect is 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, after successful pitchto US community at the ongoing Nuclear Physics Long Range Plan
Thomas Jefferson National Accelerator Facility
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• Comparable to single Z-pole measurement: shed light on 4 disagreement
• Best low-energy measurement until ILC or -Factory • Could be launched ~ 2015
Future Possibilities (Purely Leptonic)Møller at 11 GeV at JLab sin2W to ± 0.00025!
ee ~ 25 TeV reachHigher 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 In RPV B and L need not be conserved: neutralino decay
Kurylov, Ramsey-Musolf, Su
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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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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flux
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 and
first production data)
Critical Decision (CD) Presented at IPRCD-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 4QFY08CD-3B Start of Construction 2QFY09CD-4 Start of Operations 1QFY15
• JLab Upgrade only present construction project in DOE-NP
• First 11 GeV data expected in 2013
• However, plans for next upgrade already being developed now
Thomas Jefferson National Accelerator Facility
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Explore the new QCD frontier:strong color fields in nuclei
How do the gluons contribute to the structure of the nucleon? How do the gluons contribute to the structure of the nucleus? What are the properties of high density gluonic matter? How do fast quarks or gluons interact as they traverse nuclear
matter?
Precisely image the sea-quarks and gluons in the nucleon
How do the gluons and sea quarks contribute to the spin structure of the nucleon? What is the spatial distribution of the gluons and sea quarks in the nucleon? How do hadronic final states form in QCD?
Understand visible matter in terms of quarks and gluons
Thomas Jefferson National Accelerator Facility
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Projected data on Δg/g with an EIC, via + p D0 + X
K- + π+
Access to Δg/g is also possible from the g1p
measurements through the QCD evolution, and from di-jet measurements
RHIC-Spin
The Gluon Contribution to the Proton Spin
Advantage: measurements directly at fixed Q2 ~ 10 GeV2 scale!
• Uncertainties in xΔg smaller than 0.01 • Measure 90% of ΔG (@ Q2 = 10 GeV2)
Thomas Jefferson National Accelerator Facility
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ELIC ring-ring designElectron Cooling
Snake
Snake
3-9 GeV electrons3-9 GeV positrons
30-225 GeV protons 30-100 GeV/N ions
IR
IR
“Figure-8” lepton/ion rings to ensure spin preservation and easy spin manipulation
Peak luminosity up to ~1035 cm-2s-1 through short ion bunches, low β*, and high rep rate (crab crossing)
Four interaction regions with 3m “element-free” straight sections SRF ion linac concept for all ions ~ FRIB 12 GeV CEBAF accelerator, with present JLab DC polarized electron gun,
serves as injector to the electron ring.
√s = 20 - 90 GeV
Thomas Jefferson National Accelerator Facility
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LRP Recommendations1. We recommend the completion of the 12 GeV Upgrade at Jefferson Lab. The
Upgrade will enable new insights into the structure of the nucleon, the transition between the hadronic and quark/gluon descriptions of nuclei, and the nature of confinement.
2. We recommend the construction of the Facility for Rare Isotope Beams, FRIB, a world-leading facility for the study of nuclear structure, reactions and astrophysics. Experiments with the new isotopes produced at FRIB will lead to a comprehensive description of nuclei, elucidate the origin of the elements in the cosmos, provide an understanding of matter in the crust of neutron stars, and establish the scientific foundation for innovative applications of nuclear science to society.
3. We recommend a targeted program of experiments to investigate neutrino properties and fundamental symmetries. These experiments aim to discover the nature of the neutrino, yet unseen violations of time-reversal symmetry, and other key ingredients of the new standard model of fundamental interactions. Construction of a Deep Underground Science and Engineering Laboratory is vital to US leadership in core aspects of this initiative.
4. The experiments at the Relativistic Heavy Ion Collider have discovered a new state of matter at extreme temperature and density - a quark-gluon plasma that exhibits unexpected, almost perfect liquid dynamical behavior. We recommend implementation of the RHIC II luminosity upgrade, together with detector improvements, to determine the properties of this new state of matter.
Thomas Jefferson National Accelerator Facility
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LRP Recommendation #1We recommend the completion of the 12 GeV Upgrade at Jefferson Lab. The Upgrade will enable new insights into the structure of the nucleon, the transition between the hadronic and quark/gluon descriptions of nuclei, and the nature of confinement.
A fundamental challenge for modern nuclear physics is to understand the structure and interactions of nucleons and nuclei in terms of quantum chromodynamics. Jefferson Lab’s unique electron microscope has given the US leadership in addressing this challenge. Its first decade of research has already provided key insights into the structure of nucleons and the dynamics of finite nuclei.
Doubling the energy of this microscope will enable three-dimensional imaging of the nucleon, revealing hidden aspects of its internal dynamics. It will complete our understanding of the transition between the hadronic and quark/gluon descriptions of nuclei, and test definitively the existence of exotic hadrons, long-predicted by QCD as arising from quark confinement. Through the use of parity violation, it will provide low-energy probes of physics beyond the Standard Model, complementing anticipated measurements at the highest accessible energy scales.
Thomas Jefferson National Accelerator Facility
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Summary of Future Research at JLab• The Upgrade to 12 GeV at JLab is well underway (preparing for
CD-2 review this month!) with strong support from the Nuclear Physics LRP
• 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 the LQCD program 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 (ELIC) a luminosity of up to ~1035 cm-2 s-1
at a center-of-mass energy between 20 and 90 GeV for collisions between polarized electrons/positrons and ions
(A≤208)
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