Nuclear Physics at Jefferson LabPart III

R. D. McKeownJefferson LabCollege of William and Mary

Taiwan Summer SchoolJune 30, 2011

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• Meson spectroscopyand confinement

• Nucleon tomography

• Electron Ion Collider

Outline

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Quantum Numbers of Hybrid MesonsQuarks

Excited Flux Tube Hybrid Meson

S 0

L 0

J PC 0

J PC 1

1

J PC

1

1

, Klike

J PC 0 1 2

0 1 2

S 1

L 0

J PC 1

J PC 1

1

like ,

Exotic

Flux tube excitation (and parallel quark spins) lead to exotic JPC

3

4

Decay of Exotic Mesons

Possible daughters:

L=1: a,b,h,f,…L=0:,,,,…

simple decay modes such as ,, … are suppressed.

The angular momentum in the flux tube stays in one ofthe daughter mesons (L=1) and (L=0) meson, e.g:

Example: p1→b1p

flux tube L=1 quark L=1

wp→ (3p)p

or wp→ (pg)p

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5

Previous “Evidence” for 1-+ Exotic

BNL 852 (18 GeV p-)

Results are sensitive to assumption about backgroundpartial waves not robust not supported by COMPASS

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• Crays/BlueGene for Gauge Generation - capability• GPUs for physics measurements - capacity

Graphical Processor Units for LQCD

(ARRA)

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States with Exotic Quantum Numbers

Isovector Meson Spectrum

1-+

0+-2+-

Hall D@JLab

Dudek et al.

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Lattice vs. Models

Lattice

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Hall D

9R. McKeown - MENU10

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Proton Spin Puzzle

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DIS → DS 0.25[X. Ji, 1997]

HERMES

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Spinning Gluons?

D. de Florian et al., PRL 101 (2008) 072001

Global FitRHIC p + p data gluon polarization

Well maybe not….

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Proton Spin Puzzle

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[X. Ji, 1997]

X X

Consider transverse momenta

Consider orbital angularmomentum

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Wpu(x,k

T,r ) Wigner distributions

d2kT

PDFs f1

u(x), .. h1u(x)

GPDs/IPDs

d2kT drzd3r

TMD PDFs f1

u(x,kT), .. h1u(x,kT)

3D imaging

6D Dist.

Form FactorsGE(Q2), GM(Q2)

d2rT

dx &Fourier Transformation

1D

Unified View of Nucleon Structure

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Beyond form factors and quark distributions – 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

4 GPDs: H(x,x,t), E(x,x,t), H(x,x,t), E(x,x,t) ~ ~

14R. D. McKeown June 15, 2010

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Link to DIS and Elastic Form Factors

),,(~ ,~ , , txEHEH qqqq x

DIS at x =t=0

)()0,0,(~)()0,0,(

xqxH

xqxHq

q

D==

Form factors (sum rules)

[

)(),,(~ , )(),,(~

) Dirac f.f.(),,(

,

1

1,

1

1

1

tGtxEdxtGtxHdx

tF1txHdx

qPq

qAq

q

q

=x=x

=]x

òò

ò å

--

[ ) Pauli f.f.(),,(1

tF2txEdxq

q =]xò å

[ ]ò-

x+x-J G = =1

1

)0,,q()0,,q(21

21 xE xHxdxJ q

X. Ji, Phy.Rev.Lett.78,610(1997)

Angular Momentum Sum Rule

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3 dimensional imaging of the nucleon

GPDs depend on 3 variables, e.g. H(x, x, t). They describethe internal nucleon dynamics.

Deeply Virtual Compton Scattering (DVCS)

t

x+x x-x

hard vertices

2x – longitudinal momentum transfer

x – longitudinal quark momentum fraction

–t – Fourier conjugateto transverse impact parameter

g

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Extraction of GPD’s

t

hard vertices

A =Ds2s

s+-s-

s++s- =

Unpolarized beam, transverse target:

DsUT~ sinf{k(F2H – F1E)}dfE( ,x t)

DsLU~ sinf{F1H+ ξ(F1+F2)H+kF2E}df~

Polarized beam, unpolarized target:

H(x,t)

ξ=xB/(2-xB)

Unpolarized beam, longitudinal target:

DsUL~ sinf{F1H+ξ(F1+F2)(H+ξ/(1+ξ)E)}df~ H(x,t)

~

Cleanest process: Deeply Virtual Compton Scattering

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Universality of GPDs

Parton momentumdistributions

Elastic formfactors

Real Comptonscattering at high t

Single SpinAsymmetries

Deeply Virtual Meson production

Deeply Virtual Compton Scattering

GPDs

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Quark Angular Momentum

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→ Access to quark orbital angularmomentum

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Imaging the Nucleon

gives transverse spatial distribution of quark (parton) with momentum fraction x

Fourier transform of H in momentum transfer t

x < 0.1 x ~ 0.3 x ~ 0.8

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DVCS beam asymmetry at 12 GeV CLAS12

ep epg

High luminosity and large acceptance allows wide coverage in Q2 < 8 GeV2, xB< 0.65, andt< 1.5GeV2

Experimental DVCS program E12-06-119 was approved for the 12 GeV upgrade using polarized beam and polarized targets.

sinφ moment of ALU

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SIDIS Electroproduction of Pions

• Separate Sivers and Collins effects

• Sivers angle, effect in distribution function:– (fh-fs) = angle of hadron relative to initial quark spin

• Collins angle, effect in fragmentation function: – (fh+fs) = p+(fh-fs’) = angle of hadron relative to final quark spin

e-e’ planeq

Scattering Plane

target angle

hadron angle

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Access TMDs through Semi-Inclusive DIS

...]})cos(1[

...]1[

...])3sin(

...)()sin(

)sin([

...])2sin([

...)2cos(

...{

)1(2

)cos(2

2

)3sin(

)sin(

)sin(

)2sin(

)2cos(

,

2

2

2

2

Sh

Sh

Sh

Sh

h

h

LTSheT

LLeL

UTSh

ULSh

UTShT

ULhL

UUh

TUU

hhS

FS

FS

F

F

FS

FS

F

F

y

xyQdPdzddxdyd

d

Unpolarized

PolarizedTarget

PolarizedBeam andTarget

Boer-Mulder

Sivers

Transversity

Pretzelosity

f1 =

f 1T =

g1 =

g1T =

h1 =

h1L =

h1T =

h1T =

SL, ST: Target Polarization; le: Beam Polarization

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Access TMDs through Semi-Inclusive DIS

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Quark polarization

Un-PolarizedLongitudinally

Polarized Transversely Polarized

Nucleon Polarization

U

L

T

Transverse Momentum Dependent Parton Distributions (TMDs)

f 1T =

f1 =

g1 =

g1T =

h1L =

h1 =

h1T =

h1T =

Transversity

Boer-Mulder

PretzelositySivers

Helicity

Nucleon SpinQuark SpinLeading Twist

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A Solenoid Spectrometer for SIDIS

SIDIS SSAs depend on 4 variables (x, Q2, z and PT ) Large angular coverage and precision measurement of asymmetries in 4-D phase space are essential.

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SoLID Transversity Projected Data

• Total 1400 bins in x, Q2, PT and z for 11/8.8 GeV beam.

• z ranges from 0.3 ~ 0.7, only one z and Q2 bin of 11/8.8 GeV is shown here. π+ projections are shown, similar to the π- .

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Topic Hall A Hall B Hall C Hall D Total

The Hadron spectra as probes of QCD (rated) (GluEx and heavy baryon and meson spectroscopy) 1 1 2

The transverse structure of the hadrons (rated) (Elastic and transition Form Factors) 4 2 3 9

The longitudinal structure of the hadrons (rated) (Unpolarized and polarized parton distribution functions) 2 2 4 8

The 3D structure of the hadrons (unrated) (Generalized Parton Distributions and Transverse Momentum Distributions) 3 8 4 15

Hadrons and cold nuclear matter (rated) (Medium modification of the nucleons, quark hadronization, N-N correlations, hypernuclear spectroscopy, few-body experiments) 1 2 5 8

Low-energy tests of the Standard Model and Fundamental Symmetries (rated at PAC 37) 2 1 3

TOTAL 12 15 16 2 45

12 GeV Approved Experiments by Physics Topics

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Topic Hall A Hall B Hall C Hall D Total

The Hadron spectra as probes of QCD (rated) (GluEx and heavy baryon and meson spectroscopy) 119 0 120 239

The transverse structure of the hadrons (rated) (Elastic and transition Form Factors) 144 70 168 382

The longitudinal structure of the hadrons (rated) (Unpolarized and polarized parton distribution functions) 65 120 118 303

The 3D structure of the hadrons (unrated) (Generalized Parton Distributions and Transverse Momentum Distributions) 225 891 134 1250

Hadrons and cold nuclear matter (rated) (Medium modification of the nucleons, quark hadronization, N-N correlations, hypernuclear spectroscopy, few-body experiments) 5 100 139 244

Low-energy tests of the Standard Model and Fundamental Symmetries (to be rated at PAC 37) 513 79 592

TOTAL 952 1300 559 199 3010

Days in red are the requested days to be reviewed at PAC38

12 GeV Approved Experiments by PAC Days

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Electron Ion Collider

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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.”

JLAB Concept Initial configuration (mEIC):

• 3-11 GeV on 12-60 GeV ep/eA collider• fully-polarized, longitudinal and transverse• luminosity: up to few x 1034 e-nucleons cm-2 s-1

Upgradable to higher energies (250 GeV protons)

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EIC Physics Overview

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12 GeV

• 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. An EIC aims to study the sea quarks, gluons, and scale (Q2) dependence.

mEICEIC

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Medium Energy EIC@JLab

Three compact rings:• 3 to 11 GeV electron• Up to 12 GeV/c proton (warm)• Up to 60 GeV/c proton (cold)

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MEIC : Detailed Layout

cold ring

warm ring

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EIC Site Plan

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JLAB EIC Workshops• Nucleon spin and quark-gluon correlations: Transverse spin, quark and gluon orbital motion,

semi-inclusive processes (Duke U., March 12-13, 2010 )

• 3D mapping of the glue and sea quarks in the nucleon (Rutgers U., March 14-15, 2010)

• 3D tomography of nuclei, quark/gluon propagation and the gluon/sea quark EMC effect (Argonne National Lab, April 7-9, 2010)

• Electroweak structure of the nucleon and tests of the Standard Model (College of W&M , May 17-18, 2010)

• EIC Detectors/Instrumentation (JLab, June 04-05, 2010)

4/5 will produce white paper for publication

3636

General Emergent Theme

Experimental study of multidimensional distribution functions that map out the quark/gluon properties of the nucleon, including:

(quark) flavor spin and orbital angular momentum longitudinal momentum transverse momentum and position

High Luminosity over a range of energies

(Challenge to accelerator physics!)

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SIDIS SSA at EIC11 + 60 GeV3+20 GeV

Huang, Qian, et alDuke workshop

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Imaging at Low x

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Gluon Saturation

•Gluon density should saturate (unitarity)

• Access at very high E• Use large nuclei

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Phase Diagram of Nuclear Matter

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MEIC & ELIC: Luminosity Vs. CM Energy

e + p facilities

e + A facilities

For 1 km MEIC ring

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solenoid

electron FFQs50 mrad

0 mrad

ion dipole w/ detectors

ions

electrons

IP

ion FFQs

2+3 m 2 m 2 m

Detect particles with angles below 0.5o beyond ion FFQs and in arcs.

detectors

Detect particles with angles down to 0.5o before ion FFQs.Need 1-2 Tm dipole.4-

5m

Central detector

EM

Ca

lorim

ete

r

Ha

dro

n C

alo

rime

ter

Mu

on

De

tect

or

EM

Ca

lorim

ete

r

Solenoid yoke + Muon DetectorTOF

HT

CC

RIC

H

RICH or DIRC/LTCC

Tracking

2m 3m 2m

Solenoid yoke + Hadronic Calorimeter

Very-forward detectorLarge dipole bend @ 20 meter from IP (to correct the 50 mr ion horizontal crossing

angle) allows for very-small angle detection (<0.3o)

Full Acceptance Detector

7 meters

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EIC Realization Imagined Activity Name 2010 2011 2012 2013 2014 2015 2016 2017 2018 2019 2020 2021 2022 2023 2024 2025

12 Gev Upgrade

FRIB

EIC Physics Case

NSAC LRP

EIC CD0

EIC Machine Design/R&D

EIC CD1/Downsel

EIC CD2/CD3

EIC Construction

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Outlook

• The Jefferson Lab electron accelerator is currently a unique world-leading facility for nuclear physics research

• 12 GeV upgrade ensures another decade of opportunities

• Growing program addressing physics

beyond the standard model• Nucleon Tomography is a major future

theme• Large future project on the horizon: EIC