The 12 GeV Upgrade of Jefferson Lab Volker Burkert Jefferson Lab

Highlights of the 12 GeV Science Program New and revolutionary access to the structure of the proton and neutron (GPDs, TMDs) New and revolutionary access to the structure of the proton and neutron (GPDs, TMDs) Unlocking the secrets of QCD: confinement and space-time dynamics Unlocking the secrets of QCD: confinement and space-time dynamics Exploring the quark structure of nuclei Exploring the quark structure of nuclei Precision tests of the Standard Model Precision tests of the Standard Model

JLab Upgrade to 12 GeVCHL-2 Enhance equipment in existing halls Add new hall

New Capabilities in Halls A, B, & C, and a New Hall D 9 GeV tagged polarized photons and a 4  hermetic detector D Super High Momentum Spectrometer (SHMS) at high luminosity and forward angles C High Resolution Spectrometer (HRS) Pair, and specialized large installation experiments A CLAS12 with new detectors and higher luminosity (10 35 /cm 2 -s) B

New and revolutionary access to the structure of the proton and neutron

CLAS12 2m Forward Detector Central Detector Lum > cm -2 s -1 GPDs & TMDs Nucleon Spin Structure N* Form Factors Baryon Spectroscopy Hadron Formation

Generalized Parton Distributions and 3D Quark Imaging Proton form factors, transverse charge & current densities Last 50 years Structure functions, quark longitudinal momentum & spin distributions Last 40 years ? Correlated quark momentum and helicity distributions in transverse space - GPDs Last 10 years

x Deeply Virtual Compton Scattering (DVCS)  – longitudinal momentum transfer x – longitudinal quark momentum fraction – t – Fourier conjugate to transverse impact parameter Basic Process – Handbag Mechanism x B 2-x B  = GPDs depend on 3 variables, e.g. H(x, , t). They probe the quark structure at the amplitude level. What is the physical content of GPDs? t x+  x-  hard vertices 

Physical content of GPDs M 2 (t) : Mass distribution inside the nucleon J (t) : Angular momentum distribution d 1 (t) : Forces and pressure distribution Nucleon matrix element of the Energy-Momentum Tensor contains three form factors: GPDs are related to these form factors through moments

Kinematics of deeply virtual exclusive processes H1, ZEUS JLab Upgrade H1, ZEUS 12 GeV 27 GeV 200 GeV W = 2 GeV 0.7 HERMES COMPASS Study of high x B domain requires high luminosity

The path towards the extraction of GPDs Selected Kinematics  LU ~sin  {F 1 H +.  }d  e p ep  Kinematically suppressed A =           = Extract H(ξ,t)

Projected results Spatial Image Projected precision in extraction of GPD H at x = ξ

Exclusive   production on transverse target 2  (Im(AB*)) T  UT  A ~ 2H u + H d B ~ 2E u + E d 00 Q 2 =5 GeV 2 Eu, Ed measure the contributions of the quark orbital angular momentum to the nucleon spin. 00 B Should be known from DVCS Separate with ρ +

d X ( x,b ) T E d (x,t) M. Burkardt Tomographic Images of the Proton E u (x,t) u X ( x,b ) T CAT scan slice of human abdomen flavor polarization ∫ d2td2t (2  ) 2 e -i·t·b E(x,0,t) T q(x,b ) = T Target polarization The guts of the proton?

Valence structure function flavor dependence Hall B 11 GeV with CLAS12

Valence structure function spin dependence ProtonDeuteron & He-3 W > 2; Q 2 > 1

Improvements in Δu, Δd, ΔG, Δs

Important complement to RHIC Spin data

Proton electric form factor

Neutron Magnetic Form Factor At 12 GeV extend knowledge of magnetic structure of neutron to much shorter distances. Needed for constraints of GPDs at large t; related to moments of GPDs: F 1 (t)= ∫H(t,x,ξ)dx, F 2 (t)= ∫H(t,x,ξ)dx

Projections for N* Transition 12 GeV Probe the transition from effective degrees of freedom, e.g. constituent quarks, to elementary quarks, with characteristic Q 2 dependence. CLAS published CLAS preliminary CLAS12 projected

Hybrid mesons Flux Tube Model Provides a framework to understand gluonic excitations.Provides a framework to understand gluonic excitations. Conventional mesons have the color flux tube in the ground state. When the flux tube is excited hybrid mesons emerge. For static quarks the excitation level above the ground state is ~1 GeV.Conventional mesons have the color flux tube in the ground state. When the flux tube is excited hybrid mesons emerge. For static quarks the excitation level above the ground state is ~1 GeV. The excitation of the flux tube, when combined with the quarks, can lead to spin- parity quantum numbers that cannot be obtained in the quark modelThe excitation of the flux tube, when combined with the quarks, can lead to spin- parity quantum numbers that cannot be obtained in the quark model (J PC - exotics). The decay of hybrid mesons leads to complex final states.The decay of hybrid mesons leads to complex final states. 1GeV qqG qq J PC = 0 +-, 1 -+, 2 +-

LQCD supports the idea of flux tubes. Flux distribution between static quarks. Flux tubes lead to a linear confining potential.

Exotic Hybrid Mesons Masses With 3 light quarks the conventional and hybrid mesons form flavor nonets for each J PC.

Photons may be more suited to excite exotics In the flux tube model, using photon beams, the production rate of hybrid mesons is not suppressed compared to conventional mesons. N. Isgur, PRD (1999); A. Afanasev & A. Szczepaniak, PRD (2000); F. Close & J. Dudek (2004)

GlueX – Exotic meson program at 12GeV To meet these goals GlueX will:

Quark Propagation and Hadron Formation: QCD Confinement in Forming Systems How long can a light quark remain deconfined? How long can a light quark remain deconfined? The production time t p measures thisThe production time t p measures this Deconfined quarks emit gluonsDeconfined quarks emit gluons Measure t p via medium-stimulated gluon emissionMeasure t p via medium-stimulated gluon emission How long does it take to form the color field of a hadron? How long does it take to form the color field of a hadron? The formation time t f h measures thisThe formation time t f h measures this Hadrons interact strongly with nuclear mediumHadrons interact strongly with nuclear medium Measure t f h via hadron attenuation in nucleiMeasure t f h via hadron attenuation in nuclei CLAS12

Expected data – Hadronic multiplicity ratio

Color transparency in ρ electroproduction Color Transparency is a spectacular prediction of QCD: under the right conditions, nuclear matter will allow the transmission of hadrons with reduced attenuation Color Transparency is a spectacular prediction of QCD: under the right conditions, nuclear matter will allow the transmission of hadrons with reduced attenuation Totally unexpected in an hadronic picture of strongly interacting matter, but straightforward in quark gluon basis Totally unexpected in an hadronic picture of strongly interacting matter, but straightforward in quark gluon basis Why ρ? Should be evident first in mesons Why ρ? Should be evident first in mesons

The signature of CT is the rising of the nuclear transparency TA with increasing hardness of the reaction (Q) The signature of CT is the rising of the nuclear transparency TA with increasing hardness of the reaction (Q) Measurement at fixed coherence length needed for unambiguous interpretation Measurement at fixed coherence length needed for unambiguous interpretation

Predicted results high-precision, will permit systematic studies Predicted results high-precision, will permit systematic studies CLAS preliminary 56 Fe Color transparency in ρ electroproduction CLAS12 projected

Precision Tests of the Standard Model

Electron-Quark Phenomenology C 1u and C 1d will be determined to high precision by APV and Qweak C 2u and C 2d are small and poorly known: can be accessed in PV DIS New physics such as compositeness, new gauge bosons: Deviations in C 2u and C 2d might be fractionally large A V V A Proposed JLab upgrade experiment will improve knowledge of 2C 2u -C 2d by more than a factor of 20 C 1 i  2 g A e g V i C 2 i  2 g V e g A i

Parity Violating Electron DIS e-e- N X e-e- Z*Z* ** Must measure A PV to fractional accuracy better than 1% 11 GeV at high luminosity makes very high precision feasible JLab is uniquely capable of providing beam of extraordinary stability Control of systematics being developed at 6 GeV For an isoscalar target like 2 H, one can write in good approximation: provided Q 2 and W 2 are high enough and x ~ 0.3

2 H Experiment at 11 GeV E’: 6.8 GeV ± 10%  lab = 12.5 o A PV = 290 ppm I beam = 90 µA 800 hours  (A PV )=1.0 ppm 60 cm LD 2 target 1 MHz DIS rate, π/e ~ 1 HMS+SHMS x Bj ~ 0.45 Q 2 ~ 3.5 GeV 2 W 2 ~ 5.23 GeV 2  (2C 2u -C 2d )=0.01 PDG: ± 0.24 Theory:

Conclusions The JLab Upgrade has well defined physics goals of fundamental importance for the future of hadron physics, addressing in new and revolutionary ways the quark and gluon structure of mesons, nucleons, and nuclei by The JLab Upgrade has well defined physics goals of fundamental importance for the future of hadron physics, addressing in new and revolutionary ways the quark and gluon structure of mesons, nucleons, and nuclei by accessing generalized parton distributionsaccessing generalized parton distributions exploring the valence quark structure of nucleonsexploring the valence quark structure of nucleons understanding quark confinement and hadronization processesunderstanding quark confinement and hadronization processes extending nucleon elastic and transition form factors to short distancesextending nucleon elastic and transition form factors to short distances mapping the spectrum of gluonic excitations of mesonsmapping the spectrum of gluonic excitations of mesons searching for physics beyond the standard modelsearching for physics beyond the standard model Design of accelerator and equipment upgrades are underway Design of accelerator and equipment upgrades are underway Construction scheduled to begin in 2009 Construction scheduled to begin in 2009 Accelerator shutdown scheduled for 2012 Accelerator shutdown scheduled for 2012

2007 NSAC Long Range Plan (4 recommendations) We recommend the completion of the 12 GeV Upgrade at Jefferson Lab. - It 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. -It will test definitively the existence of exotic hadrons, long- predicted by QCD as arising from quark confinement. -It will provide low-energy probes of physics beyond the Standard Model complementing anticipated measurements at the highest accessible energy scales. Recommendation 1

DOE Generic Project Timeline We are here DOE Reviews

A first search for exotic meson with photons a1a1 a2a2 p2p2 Gluonic Meson? p 1 (1600) Events/ 20 MeV  Clarify evidence for exotic meson states, e.g. at 1600 MeV with high statistics.  Prepare for full study with GlueX. Events from previous CLAS experiment. Expect 1-2 million 3-pion events, 3 orders more than any previously published meson photoproduction results, allowing a partial wave analysis. Experiment planned to run in 2008.

Physical content of GPDs M 2 (t) Mass/energy density J(t) Angular momentum density In the Chiral Quark Soliton Model d 1 (t) Pressure density repulsion attraction

CLAS12 - DVCS/BH Target Asymmetry e p ep  Longitudinally polarized target  ~sin  Im{F 1 H +  (F 1 +F 2 ) H... }d  ~ E = 11 GeV L = 2x10 35 cm -2 s -1 T = 1000 hrs  Q 2 = 1GeV 2  x = 0.05

DVCS DVMP Separating GPDs in Flavor & Spin hard vertices  DVCS depends on all 4 GPDs  Photons cannot separate u/d quark contributions. M =     select H, E, for u/d quarks M =  select H, E Isolate longitudinal photons by decay angular distribution.

CAT scan slice of human abdomen liver right kidney pancreas stomach gall bladder Can we do similar imaging in the microscopic world? Tools are being developed to add this new dimension to nuclear research.

z y 3-D Scotty x GPDs & PDFs Deeply Virtual Exclusive Processes & GPDs 2-D Scotty z x 1-D Scotty x probablity Calcium Water Carbon Deep Inelastic Scattering & Parton Distribution Functions.

X. Ji and F. Yuan, D image obtained by rotation around the z-axis Charge density distributions for u-quarks y z Tomographic Images of the Proton II x= fm fm x= fm fm x= fm -220fm interference pattern 10