The Jefferson Lab 12 GeV Program

The Jefferson Lab facilities have undergone a substantial upgrade, both of accelerator, CEBAF, and of the experimental installations. We will discuss

the progress to completion of these facilities, the status of accelerator commissioning, and the recent first operations for physics. We will then

flesh out the anticipated exciting physics program of the next several years.

Hugh Montgomery Jefferson Lab

International Nuclear Physics Conference 2016

H. E. Montgomery 2 The International Nuclear Physics Conference 2016

Acknowledgements

The 12 GeV Program at Jefferson Lab has taken many years from its inception in the previous millennium to its realization as an important

pillar of the world nuclear physics program in the 21st Century.

I would like to acknowledge the input and contributions from the staff and users of Jefferson Lab who have made this exciting program possible. In particular, much of the material was shown by Bob McKeown at Hadron

Workshop 2016 in China, and some of the output from the GlueX experiment was presented by Curtis Meyer at Meson 2016.

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Outline •  12 GeV CEBAF

•  Status of the Experiments

•  12 GeV Physics Program –  Meson Spectroscopy, Hybrid Mesons, and Confinement –  Nucleon Tomography –  Nuclei and Nuclear Structure –  The Standard Model and Beyond

•  Conclusions

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CEBAF Upgrade

“With the imminent completion of the CEBAF 12-GeV Upgrade, its forefront program of using electrons to unfold the quark and gluon structure of hadrons and nuclei and to probe the Standard Model must be realized”

TPC = $338M ETC = ~$8M

Project Scope (~98% complete): •  Doubling the accelerator beam energy – DONE •  New experimental Hall D and beam line – DONE •  Civil construction including utilities – DONE •  Upgrades to Experimental Halls B & C – ~96%

o  Halls B & C Detectors – DONE

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CEBAF Commissioning Highlights Spring 2015: •  First simultaneous Hall A/D operations •  Successful commissioning runs:

Hall B (Heavy Photon Search) and Hall D (GlueX)

Fall 2015: •  First operation of CEBAF at design energy

A & D beam separated on 5th pass at 9.6 GeV

D: 1st production polarized photons

Spring 2016: •  Hall D engineering run complete •  Hall A commissioning and early physics run •  Hall B HPS on weekends, extended run

Summer 2016: •  Proton Radius Experiment (PRad) •  First completed experiment in 12 GeV era!

Accelerator ready for 12 GeV physics program

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GlueX in Hall D

•  New experiment to study quark confinement •  Commissioning complete •  Detector functioning well •  Production data-taking started •  Poised to discover exotic hybrid mesons

barrelcalorimeter

time-of-flight

forward calorimeter

photon beam

electronbeamelectron

beam

superconductingmagnet

target

tagger magnet

tagger to detector distanceis not to scale

diamondwafer

GlueX

central driftchamber

forward driftchambers

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CEBAF 2014 Commissioning: Hall D •  Achieved 12 GeV Project Hall D performance parameters (December 2014) •  Delivered beam quality met the initial years user requirements (e, dp/p, polarization…) •  Beam delivered to 3 Halls simultaneously

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12 GeV Upgrade Project Remaining scope & status: •  Hall C superconducting dipole, 2 quads

o  All magnets assembled, leak-checking & welding in progress o  Q2 quadrupole left Vannes in late August

•  Hall B superconducting torus, solenoid o  Torus in cool-down o  Solenoid: (coils 1 – 4, and coil 5 mated) cold mass assembled

Most key technical risks retired. Proactively managing work at vendors to minimize schedule delays.

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Jefferson Lab @ 12 GeV Science Questions •  What is the role of gluonic excitations in the

spectroscopy of light mesons? •  Where is the missing spin in the nucleon?

Role of orbital angular momentum? •  Can we reveal a novel landscape of nucleon

substructure through 3D imaging at the femtometer scale?

•  Can we discover evidence for physics

beyond the standard model of particle physics?

excited gluon field

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12 GeV Approved Experiments by Physics Topics Topic Hall A Hall B Hall C Hall D Other Total The Hadron spectra as probes of QCD (GluEx and heavy baryon and meson spectroscopy) 2 1 3 6

The transverse structure of the hadrons (Elastic and transition Form Factors) 5 3 3 1 12

The longitudinal structure of the hadrons (Unpolarized and polarized parton distribution functions) 2 3 6 11

The 3D structure of the hadrons (Generalized Parton Distributions and Transverse Momentum Distributions)

5 9 7 21

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

7 3 7 1 18

Low-energy tests of the Standard Model and Fundamental Symmetries 3 1 1 1 6

TOTAL 22 21 24 5 2 74

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Meson & Baryon Spectroscopy Hybrid Mesons

Confinement

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Isospin 1 Meson Spectrum

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Degr

ee of

Polar

izatio

n

0.0

0.2

0.4

0.6

0.8

1.0

Energy [MeV]0 2000 4000 6000 8000 10000 12000

Model Fit to Coherent Enhancement

-150 -100 -50 0 50 100 150q [degrees]

dN/dq�

[Arb

itrary

Unit

s]

-150 -100 -50 0 50 100 150

��Polarization || Polarization

q [degrees]

Lab Floorl Decay Plane

l

/

/<

Photon Beam

Polarization Planeq

|| Polarization

-0.3

-0.2

-0.1

0.0

0.1

0.2

0.3

-150 -100 -50 0 50 100 150q [degrees]

Asym

metry

d�? / 1� P?⌃ cos 2� d�k / 1 + Pk⌃ cos 2�P⌃ cos 2� =

Nk �N?

Nk +N?

~40% Polarization

Large polarization transfer to the r

Between 100 and 1000 times the 3000 existing events from SLAC. Working with JPAC on models for analysis

Acceptance errors not included

Beam Asymmetry in ρ Photoproduction

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M(4γ) [GeV/c2]0.0 0.5 1.0 1.5 2.00

100

200

300

400

500

020406080

100120140160180200220

Cand

idates

/ 10 M

eV/c2

0.0 0.5 1.0 1.5 2.0 2.5M(4γ) [GeV/c2]

Cand

idates

/ 10 M

eV/c2

/�/� Region d/� Regionf2(1270)

m f0(980)

a0(980)

a2(1320)

0.0 0.2 0.4 0.6 0.8 1.00.0

0.2

0.4

0.6

0.8

1.0

1

10

210

310

M(γγ) for Pair 1 [GeV/c2]

M(γγ

) for P

air 2

[GeV

/c2 ]

d/�

d/�

/�/�

�p ! p����

⇡0⇡0

⌘⇡0

⇡0⌘

⌘⌘

About 6% of the spring 2016 statistics from early in the run and using a very preliminary production run. Clear signals for σ, f0(980), f2(1270), a0(980) and a2(1320).

Four Photon Final States

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Charmonium Pentaquark LHCb 2 Pc states needed to describe results:

narrow: Pc(4450) wide: Pc(4380)

JLab E12-16-007

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Nucleon Tomography

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Solving the Proton Radius Puzzle

Atomic H Elastic e-p scattering

Muonic H

(projected)

•  PRad: new experiment to address proton radius @ JLab •  NSF MRI: H2 gas target •  DOE GEM tracking detectors •  Successful run in summer 2016!

PRad@JLab:

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3D Mapping of the Nucleon

Transverse Spatial Imaging Transverse Momentum Imaging

GPDs: Longitudinal momentum fraction x at transverse location b

TMDs: Longitudinal momentum fraction x and transverse momentum k

Q2

t

ξ+x ξ−x

Bjxx ≠Bjx~ξ

e e’ γ*

P X

h }

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Imaging with JLab @ 12 GeV Generalized Parton Distributions (GPDs) and Transverse Momentum Distributions (TMDs)

•  CLAS12 in Hall B: general survey experiments, large acceptance and medium luminosity

•  SHMS, (HMS) and Neutral-Particle Spectrometer (NPS) in Hall C: precision cross sections for L-T studies and ratios, small acceptance and high luminosity

•  SBS in Hall A : dedicated large-x TMD study medium acceptance and high luminosity

•  Future: SoLID in Hall A: large acceptance and high luminosity

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The Incomplete Nucleon: Spin Puzzle

•  DIS → ΔΣ ≅ 0.25 •  RHIC + DIS → ΔG~0.2 •  → Lq CEBAF 12 GeV

[X. Ji, 1997]

ΔΣ Lq Jg + + 1 2 = 1

2

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3D Imaging Program at Data at 11 GeV

•  High impact experiment for nucleon 3D imaging program

•  16% of experiment completed in 2014-2016

Hall A Data reconstructed in calorimeter

Missing Mass Reconstruction (1.5 h of beamtime)

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Nuclei and Nuclear Structure

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Measuring the Neutron “Skin” in the Pb Nucleus

Applications: Nuclear Physics, Neutron Stars, Atomic Parity, Heavy Ion Collisions

Qwp =(1 – 4 sin2 θW)

QWn = -1

Weak interaction selects neutrons

•  Parity violating electron scattering •  Sensitive to neutron distribution

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Beyond QCD Nuclear Structure and Reactions

•  Future CEBAF data will determine the thickness of the neutron skins in a Pb, 40Ca, 48Ca nucleus which is related to the radius of a neutron star.

•  Future CEBAF data on hypernuclei should test

explanations of why neutron stars with masses twice that of our sun exist.

Nuclear Astrophysics

•  Future CEBAF injector data on γ+16O � 12C +α will

provide new information constraining the Carbon/Oxygen ratio in our universe.

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The Standard Model and Beyond

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Heavy Photon Search

•  HPS searches for an electro-produced hidden sector photon (A’) which decays to e+e- pairs

•  A’s could mediate dark matter annihilations and interactions with our matter

•  HPS identifies A’s with invariant mass and separated vertices

Measured e+e- Mass Status: •  1 GeV data under analysis

o  first results this summer •  2 GeV data acquired in spring 2016

o  results next year •  More running in the future •  NP-HEP Collaboration

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Testing the Standard Model at JLab

Standard Model

Projected JLab data:

JLab Data

(from PDG 2014)

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Summary •  The 12 GeV Project is near to completion

•  Elements of the 12 GeV Physics Program are established and operational in Halls A and D

•  The detectors for Halls B and C are in their final phases of construction and will be commissioned during 2017

•  The Physics program will be an exciting and perhaps dominant component of the Medium Energy Physics worldwide during the next decade.

It is a very exciting time at Jefferson Lab!!!