6 gev program overview rolf ent pac38 meeting august 22 nd 2011 hallphysics began experiments...
DESCRIPTION
Ongoing 6 GeV Program Issues remaining: Completion of g2p/GEp apparatus in Hall A Proof of polarized HDIce operations in Hall B Sufficient beam in Hall CTRANSCRIPT
6 GeV Program Overview
Rolf EntPAC38 Meeting
August 22nd 2011Hall Physics
BeganExperimentsCompleted(full/partial)
ExperimentsCompleted(equivalent
C 10/95 37 / 6 40.1 A 5/97 62 / 0 62.0B 11/97 75 / 5 78.6
Totals Today 174 / 110 180.7Totals PAC37 168 / 120 174.6
Good FY11 Operations
• Did run as promised until May 13, 2011 & started 6 Month Shut Down work• Cumulative delivered beam used: Hall A 101% (routine running)
Hall B 70% (HDIce delay)Hall C 82% (Qweak catching up)
Ongoing 6 GeV Program
Issues remaining:• Completion of g2p/GEp apparatus in Hall A• Proof of polarized HDIce operations in Hall B• Sufficient beam in Hall C
Year(Expt. #)
Experiment Major Installation Tasks Special Accel. Requirements
ScientificRating
PAC Days
FY2010
E05-109 HAPPEx-III Completion Small helicity correlations(~ 1/20*HAPPEX I)
A- Complete
E08-011 DIS-parity High-speed DAQ A- 32
E06-002 PREx: Lead Parity Room-temperature septaMøller and Compton upgrade
Small helicity correlations(~ 1/20*HAPPEX I)
A 30
E07-007E08-025
DVCS on the proton and neutron
PbF2 calorimeter A, B+ 40
FY2011
E07-007E08-025
DVCS on the proton and neutron
Completion A, B+ 40
E08-008 Deuteron electrodisintegration near threshold
BigBite B+ (C3) 18
E08-010 N-D Coulomb quadrupole amplitude at low Q2
B+ 3
E07-006 Short Range Correlations via (e,e’pN)
BigBite A- 23
E08-009 4He Nuclei Response Functions
C3 0.5
E08-014 Three-nucleon correlations (x>2)
A- 12
Accelerator Down for 12 GeV Work
Now UnderwayNot shown on the FY2010 Schedule is the APEX test run; it took place just after PREx
Hall A: Ongoing 6 GeV Program
Page 5
Lead (208Pb) Radius Experiment : PREXElastic Scattering Parity-Violating Asymmetry
Z0 : Clean Probe Couples Mainly to Neutrons
Applications : Nuclear Physics, Neutron Stars, Atomic Parity, Heavy Ion Collisions
• The Lead (208Pb) Radius Experiment (PREX) finds neutron radius larger than proton radius by +0.35 fm (+0.15, -0.17).
• This result provides model-independent confirmation of the existence of a neutron skin relevant for neutron star calculations.
• Follow-up experiment to reduce uncertainties by factor of 3 and pin down symmetry energy in EOS.
A neutron skin of 0.2 fm or more has implications for our understanding of neutron stars and their ultimate fate
Relativistic mean field
Nonrelativistic skyrme
PREXPREX
Page 6
HAPPEx-III results final, publication in preparation - accurate measurement at Q2 = 0.6 GeV2, completing the parity-violating program constraining
the contributions of strange quarks to the proton’s charge & magnetization.- contributions to these distributions are found to be minimal.- strange quarks do not play a substantial role in the long-range electromagnetic structure of
nucleons
Strangeness Contribution to Nucleon Form Factors
Completes Performance Measure HP4
Pink line represents 2% of the proton form factors (in the same combination of electric and magnetic as the strange form factors) strange quarks represent less than 2% of the proton form factors.
Page 7
Searches for a gauge boson A’ – APEX Test Run Result
Future searches for a new force carrier:- APEX – electron-nucleus fixed-target, an e+e- pair in two focusing spectrometers- HPS – same, the e+e-, m+m- pairs in a custom Si-tracker magnetic spectrometer- DarkLight – an internal target with an electron beam in Jefferson Lab ERL, detect an e+e- pair and e’p - VEPP3 – a positron beam incident on an internal H2 target, missing mass in (e+e-, g X) - MAMI – APEX type scheme with lower beam energy
Electroproduction of A’
decay
Published results :- Beam dump searches: SLAC:E137, 141; FNAL: E774- electron and muon (g-2), limits- BaBar, U(3s)-> g and m+m- (inferred limit)- KLOE, mass of an e+e- pair (bump search)- APEX test run, mass of e+e- pair – arXiv:1108.2750- MAMI – APEX type scheme
Year(Expt. #)
Experiment Major Installation Tasks Special Accel. Requirements
ScientificRating
PAC Days
FY2012Accelerator Down for 12 GeV work
E08-027 g2p and the LT Spin
polarizabilitySepta + beamline chicanePolarized target
A- 24
E08-007 GEp at low Q2 A- 14
E08-027 g2p and the LT Spin
polarizabilityCompletion A- 24
E07-012 Hypernuclear 16O and production
Septa B+ 12
Last piece of incremental equipment funding provided by DOE/NP
Hall A: Upcoming Program up to May 2012 Shutdown for 12-GeV
installation
Removed from schedule due to extended time needed for g2p /Gep transitions
• Hall A submitted draft plan for initial operations in FY14-FY16 to Director, expected to continue iterations in 2011• MIE for Super Bigbite System submitted to DOE, DOE science & technical review scheduled for October 13 + 14• Draft MIE proposal for Moller experiment in hand
Year(Expt. #)
Experiment Major Installation Tasks Special Accel. Requirements
ScientificRating
PAC Days
FY2010
E07-009E08-024
Eg6: DVCS and meson spectroscopy on 4He
Modified e1-DVCS setup Standard (E>5.9GeV)
A, A- 45
E02-112E03-105E04-102E05-012E06-013
G9 – FrostMissing N* Resonances(completion – started in 2008)
Frozen spin target Standard3 A-, 2B+ 91 (remaining 60
days here)
Install PRIMEx-II
FY2011
E08-023 PRIMEx-II Re-Install PRIMEx Beam Stability A- 20
E07-005 EG5-Two Photon exchange in elastic e+p/e-p scattering
Installation of conversion/target apparatus
Standard A 35
Install HDIce & Commission
E06-101 G14 – N* Searches (HDIce) (& electron test)
HD polarized target Standard A 7
Accelerator Down for 12 GeV work
FY2012
Accelerator Down for 12 GeV workE06-101E08-015E08-021
G14 Completion, then DVCS and SIDIS w/ HDIce Target
Conversion of HD polarized target for electron beam operation
Standard A, A and A- 65
Technical feasibility to be established
Almost …
Hall B: Ongoing 6 GeV Program
HDice commissioningApril-May/11 • In-beam Cryostat (IBC) passed ASME pressure-code tests • IBC installed in CLAS and aligned • LHe circuit cooled; auto-fill from ESR established • magnets (3 superconducting, 1 normal) commissioned at full current • in-beam NMR successfully tested • test transfer of solid HD from HDice Lab -to- Hall B –to- IBC
• low target temperatures prevented by blocked capillary
First photo sent to us from HDIce in Hall B April 2011
HDice commissioningMay-August/11 • Blocked capillary was found to be piece of low-tech solder • Achieved 48 mK July 31, 2011 (and I believe they reached 43 mK in the end) •Produced additional three spare polarized target batches in July/August
• IBC moved to Hall B again last week
• Start cooling when ESR availability permits
• Need to do HD spin transfer tests in Hall
Beam-spin asymmetry for π0 SIDIS A 5.75 GeV polarized electron beam was used with CLAS to measure the azimuthal dependence of the beam spin asymmetry for in a large xB, and PT range.
Significant asymmetries are observed for 0.3<PT<0.7 GeV and in the range xB ≤ 0.4. Structure function FLU receives contributions from contributions from the convolution of twist-2 and twist-3 distribution and fragmentation functions, e.g. twist-2 Boers-Mulders DF, Collins FF and twist-3 DFs e and g T
The observed asymmetry for π0
suggests that the major contribution to pion beam SSA originates from spin-orbit correlations.
ep e’π0X
M. Aghasyan et al. (CLAS), arXiv:1106.2293, PLB accepted
Year(Expt. #)
Experiment Major Installation Tasks Special Accel. Requirements
ScientificRating
PAC Days
FY2010E05-115 HKS/HES (completion) Run to completion Energy stability of
10-4, Position stability < 100 mm
A- 20
E08-016 QWeak (Install and begin commissioning)
Major installation6 months
Complete overhaul of Hall C beamlineNew PolarimeterMajor Cryo Load See Published Beam Specs.
A 198
FY2011E08-016 QWeak (complete
commissioning and run Phase I)
See Published Beam Specs.
A 198
Accelerator Down for 12 GeV work
FY2012Accelerator Down for 12 GeV work
E08-016 QWeak (run Phase II) See Published Beam Specs.
A 198
Now Underway
Hall C: Ongoing 6 GeV Program
Hall C: Qweak status
σ = 236 ppm
Asymmetry Width• Beam: routine data-taking at 165 μA @ ~88% polarization (and tests up to 180 mA)• Helicity-correlated properties acceptable!
Status at 05/13/11
• Precision measurement of the proton’s weak charge in the simplest system• Search for parity-violating new physics up to the ~ 2 TeV scale• No show-stoppers found, on track for proposed 4% precision on Qp
Weak
Above: 6.5 minutes of data @ 165 μATotal detected rate = ~5.83 GHzPure counting statistics: ~215 ppm+ detector energy resolution -> 232 ppm+ beam current normalization -> 235
ppm agrees with data
Evolution of PVES Helicity Correlated Beam Properties
Qweak Run Average
8 ± 15 x: 3.9 ± 0.5y: -5.7 ± 0.5
x’: -0.11 ± 0.02
y’: -0.00 ± 0.02
The QWEAK Experiment: Measurement of the Proton’s Weak Charge
Elastic ep Scattering Parity-Violating Asymmetry
Anticipated constraints if QP
W is consistent with the Standard Model.
MS Theory Curve : J. Erler, M. J. Ramsey-Musolf et al.,See Particle Data Group 2010
Anticipated QPW
uncertainty:
Run I (completed)
Run I + Run II
Q (GeV)
• First direct measurement of the proton’s weak charge.• Precision determination of the neutral current weak couplings
to the quarks (C1u & C1d).• Mass scale reach for parity-violating new physics at expected
final uncertainty (95% CL) is ~2.3 TeV.
Isovector weak charge
sin2 q
W
QPW = - 2 (2C1u + C1d )
Young, Carlini, Thomas & Roche, PRL
Isos
cala
r wea
k ch
arge
The TAC Process
Please note that for this PAC, we have asked a team of experienced and critical scientists, representing all Hall groups to look at some of the more technically challenging proposals. You will find the comments of this technical review attached to the individual reports. Our hope is, that this will be useful to both the PAC and the experiment proponents, and adds a layer of coherence to the technical review process.
If a proposal was selected, this simply reflects our feeling that the proposal could benefit from this independent technical review. On the other hand, if a proposal was not selected, it does not mean it will not have technically challenging components. We welcome any feedback you might have on the use of this independent technical review process.
Added for PAC38 an independent technical review process, and tried this on five proposals
The 12 GeV PAC Process (cont.)Planning the Initial Operation in Each Hall
Following the model used for the initial CEBAF program, ~2-3 years before start of 12 GeV operation hall-by-hall:
• Each hall will provide for PAC review and comment (and potential improvement) a “commissioning and early running” plan folding in guidance of DOE/NP on early operations in FY14-FY16.
• The collaboration’s tradeoff between the best possible science and the realities of commissioning equipment.
• 3 years after the start of physics in each hall, jeopardy will begin.
• Status: Hall A early draft submitted to Director and iterations ongoing, Hall B plan started, Hall C plan just discussed at Summer workshop. Submit all for PAC review and comments Summer 2012?