Jefferson Lab Science

Bob McKeownJune 4, 2015

2April 2015

Outline

• Recent Highlights

• PAC

• Experimental equipment

- SBS

- Enhancements beyond 12 GeV project

• MOLLER, SoLID status

• MEIC

3April 2015 3

Momentum Sharing in Imbalanced Fermi Systems

• At momentum greater than the Fermi momentum (kf), the fraction of proton-neutron pairs dominates in atomic nuclei. It was recently found that even in neutron-rich heavy nuclei proton-neutron pairs dominate over proton-proton and by inference neutron-neutron pairs [1].

• The implication of this pairing is that, even if there are far more neutrons than protons in nuclei, the proton momentum above kf is near-identical to that of the neutron – the momentum is shared.

• This is confirmed in nuclear theory calculations for light nuclei [2], and results in an on average higher proton than neutron momentum, as suggested for neutron-rich nuclei [3].

This is completely unlike the effects for non-interacting Fermions in a mean field, and has implications for the equations of state of neutron stars and atomic interactions in ultra-cold atomic gases. [1] The data were analyzed by the CLAS Data Mining Initiative.

[2] R. Wiringa et al., Phys. Rev. C 89, 024305 (2014)[3] M. Sargsian, arXiv:1210.3280 (2012); PRC 89, 034305 (2014)

CEBAF Large Acceptance Spectrometer (CLAS)

O. Hen et al., Science 346 (2014) 614, doi:10.1126/science.1256785

The Jefferson Lab CLAS CollaborationSelected for Science Express (16 October 2014)

4April 2015

Exploring Proton Structure with Electrons and Positrons

• The proton electric form factor GEp, describes the proton

charge distribution.

• There is a discrepancy between GEp measurements with

polarized and unpolarized electrons.

• The positron to electron (e+p/e−p) ratios agree with hadronic two photon exchange calculations, which would resolve the proton form factor discrepancy up to Q2 ~2.5 GeV2. This also has relevance for the proton radius extraction.

D. Adikaram et al. (Jefferson Lab CLAS Collaboration), Phys. Rev. Lett. 114 062003 (2015). DOI: http://dx.doi.org/10.1103/PhysRevLett.114.062003

Unpolarized Measurements

Polarized Measurements

• This big discrepancy is possibly due to two photon exchange, which can’t be calculated exactly.

• Comparing electron and positron scattering off protons directly measures the two photon exchange correction.

• A mixed electron and positron beam was produced in Jefferson Lab’s Hall B. Complementary experiments at VEPP-3 at Novosibirsk and OLYMPUS at DESY used sequential beams.

• The scattered electron or positron and struck proton were detected in the CEBAF Large Acceptance Spectrometer.

The e+p and e−p cross section ratio versus virtual photon polarization ε at Q2 = 1.5 GeV2.

5April 2015

Theory and Computation HighlightNew Technology + Innovative Techniques

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p h,Lattice QCD Advance: First scattering calculation of Inelastic channels

Work on leadership GPU systems such as DOE Titan (ORNL) and

NSF Blue Waters (NCSA - University of Illinois) Large ASCR Computing Challenge Awardin May 2014: 250M core hours

Now published in PRL

published

6April 2015

Polarized ρ Production with the Hall D Photon Beam

7April 2015

Heavy Photon Search

7

HPS tracked pairs

• Engineering run in Hall B• CE from DOE-HEP

8April 2015

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)   1   3 4

The transverse structure of the hadrons(Elastic and transition Form Factors) 5 3 2 1 11

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)

6 3 7   1 17

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

TOTAL 21 20 22 5 2 70

9April 2015

12 GeV Approved Experiments by PAC Days

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)   119 540 659

The transverse structure of the hadrons(Elastic and transition Form Factors) 145.5 85 102  25 357.5

The longitudinal structure of the hadrons  (Unpolarized and polarized parton distribution functions) 65 230 165  460

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

409 872 212   1493

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

180 175 201  14 570

Low-energy tests of the Standard Model and Fundamental Symmetries 547  205  79 60 891

TOTAL 1346.5 1686 680 644 74 4430.5

10April 2015

PAC Membership

• Retired last year:– N. Makins– M. Vanderhaegen– J. Ahrends– B. Sherrill

• New members starting this year:– R. Fatemi– F. Maas– D. Dean– W. Vogelsang

• New PAC Chair: J. Napolitano

11April 2015

PAC43Scheduled for week of July 6Proposals due 8AM EDT Monday, May 18, 2015

Charge:

Review new proposals, previously conditionally approved proposals, and letters of intent for experiments that will utilize the 12 GeV upgrade of CEBAF and provide advice on their scientific merit, technical feasibility and resource requirements. Identify proposals with high-quality physics that, represent high quality physics within the range of scientific importance represented by the previously approved 12 GeV proposals and recommend for approval.

Also provide a recommendation on scientific rating and beam time allocation for proposals newly recommended for approval.

Identify other proposals with physics that have the potential for falling into this category pending clarification of scientific and/or technical issues and recommend for conditional approval. Provide comments on technical and scientific issues that should be addressed by the proponents prior to review at a future PAC.

8 new proposals2 run group additions7 LOI’s

12April 2015

CAD drawing of SBS magnet and infrastructure

Super Bigbite Spectrometer (SBS)New spectrometer to support three form factor experiments (GE

P high impact), and one SIDIS experiment in Hall A.

Magnet and infrastructure (JLab) 2400 channel scintillator hodoscope (ISU) 40 GEM modules ( each area = 50x60cm2) for

rear tracker (UVa) Other equipment: Hadron calorimeter (CMU),

Cerenkov (W&M), Front Tracker GEMs (INFN), Electron Calorimeter (SBU & JLab) and polarized helium target (UVa)

04/22/202312

Magnet tested at JLab

Power supply tested at JLab

13April 2015

Super Bigbite Spectrometer (SBS)

Clean room for GEM construction

04/22/202313

R&D on polarized 3He target at UVa to reach 60cm length and sustain 60uA beam

Hadron calorimeter module at CMU. Production started in April.

• UVa is in full GEM module production mode.• 12 of the 40 GEMs have been constructed and passed

Q&A tests

Cosmic ray test stand for Q&A

Postdoc and grad student constructed a GEM

14April 2015

Future Projects

• MOLLER experiment (Possible MIE – FY17-20)

– Standard Model Test– DOE science review (September 2014) – strong endorsement- Technical, cost & schedule reviews?

• SoLID – Chinese collaboration

– CLEO Solenoid – Director’s review (Feb. 2015)

lots of good feedback

15April 2015

JLab MEIC Figure 8 ConceptInitial configuration:• 3-10 GeV on 20-100 GeV ep/eA collider• Optimized for high ion beam polarization:

polarized deuterons• Luminosity:

up to few x 1034 e-nucleons cm-2 s-1

Low technical riskUpgradable to higher energies

250 GeV protons + 20 GeV electrons

Flexible timeframe for Construction consistent w/running 12 GeV CEBAF

Thorough cost estimate completedpresented to NSAC EIC Review

Cost effective operations

Fulfills White Paper Requirements

Current ActivitiesSite evaluation (VA funds)Accelerator, detector R&DDesign optimizationCost reduction

EIC at Jefferson Lab

15

16April 2015

MEIC Baseline DesignFeatures:• Collider ring circumference: ~2100 m• Electron collider ring and transfer lines : PEP-II magnets, RF

(476 MHz) and vacuum chambers• Ion collider ring: super-ferric magnets • Booster ring: super-ferric magnets• SRF ion linac

16

17April 2015

NSAC EIC Cost Review – Jan 26-28

From the Charge:Understanding that a detailed conceptual design has not been completed, the Subcommittee is asked to provide NSAC with its best current estimate of the costs of the projects, including R&D, construction, pre-operating and operating costs. NSAC is aware that there are uncertainties regarding siting and other issues that limit the precision of such an estimate at this time. Nevertheless, the advice of the Subcommittee will be of great value to NSAC as it evaluates the relative merit of this and other initiatives. Since the charge to NSAC for the long range plan explicitly discusses resources in terms of the 2015 President’s Budget Request, we ask that the results of this review be presented in FY2015 dollars. If the laboratories choose to present staging options to incrementally reach the science goals, please consider these as well.

The subcommittee is asked to provide a written report to NSAC by the end of February 2015. I expect it will be considered by NSAC in a meeting in late March 2015.

18April 2015

Level 2 Cost Estimate (k$, FY15, w/OH)

Scope Contingency 1.1. CDR 4,656 1,629

1.2. Accelerator 692,285 271,740

1.4. Conv. Facilities 210,349 42,070

1.5. Integrated comm. 37,327 13,064

1.6. Management -Project 13,411 4,694

Total 1,291,255

1.3. Exp. Systems 126,639 61,418

188,056

L. Harwood – NSAC Cost Review

19April 2015

Cost Review Presentation to NSAC

20April 2015

MEIC Life Cycle Cost (FY15$)• TPC without detector = $1.29B

• TPC with large acceptance detector = $1.48B

• Ops = $0.117B/year x 15 years = $1.76B

• MEIC Total (w/detector): construction + ops (15 years) = $3.24B

• 20% of the anticipated NP budget over a 25 year (construction+operation) period – presently CEBAF operations is 16%– presently RHIC operations is 28%

• CEBAF (6 GeV): construction + ops (1996-2014) = $2.98B

→ NP community can manage this scale.

21April 2015

Future EIC activities

• POETIC VI - Sept. 7-11, Palaiseau, France

• MEIC Collaboration meeting in October

• EIC User meeting (joint with eRHIC) late 2015

• User workshops to advance science case?

22April 2015

Summary and Outlook

• Physics Output from 6 GeV is healthy

• Experiments on the floor are doing well

• SBS making good progress

• Trying to move MOLLER and SoLID along

• EIC science and designs are making good progress

• Awaiting results from NSAC Long Range Plan