Future Research at Jefferson Lab 12 GeV and Beyond Kees de Jager Jefferson Lab INPC2007 Tokyo

Thomas Jefferson National Accelerator Facility

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


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


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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


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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


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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


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A1p at 11 GeV

Unambiguous Resolution of Valence SpinA1

n at 11 GeV


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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


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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


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


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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


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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


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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


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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


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• Exotic Meson Spectroscopy: Confinement and the QCD vacuum

• Nuclei at the level of quarks and gluons

• Tests of Physics Beyond the Standard Model


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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


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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-+


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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-+


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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


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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


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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


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•Generalized Parton Distributions and Form Factors





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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


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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


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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


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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


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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


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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


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Hall C - Side View of SHMS Design


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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


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Tagger Spectrometer(Upstream)

Hermetic detectionof charged and neutral particles

Hall D - GluEx Detector


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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


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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


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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)


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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


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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.


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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.


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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)

Future Research at Jefferson Lab 12 GeV and Beyond Kees de Jager Jefferson Lab INPC2007 Tokyo

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