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CHL-2CHL-2
Enhance equipment in existing halls
Add new Add new hallhall
Jefferson Lab, latest results and the 12GeV UpgradeKen Livingston, University of Glasgow.
Nuclear Physics UK Community MeetingCosener’s House 11th & 12th June 2009
CEBAF, Jefferson Lab, Virginia. 6 GeV racetrack configuration. > 200uA to 3 experimental areas
CLAS Spectrometer (Hall B) Polarisation observables in strangeness production
BigBite (Hall A) Gen - neutron electric form factor
“Highest priority”STFC Programmatic
review
Jlab 12GeV Upgrade $310MHighest priority in the DoE/NSF NSAC long
range plan
Approval to begin construction phase (CD3) in 2008.
CLAS 12 (Hall B)
Generalised Parton Distributions (GPDs)
Quasi-Real photon beam
Super BigBite (Hall A)
Form factors, compton scattering
GlueX (Hall D)
QCD exotics
• > 1000 scientists, 200 institutes, 20 countries
• No annual costs, No running costs.
• We provide expertise and additional hardware.
• Value for money.
• UK groups – Glasgow, Edinburgh (UWS ?)
CLAS - Missing resonances and resonance spectroscopy
• Constituent quark models predict many resonances.
• Some missing – undetected or wrongly predicted ?
• Most data from pion beam expts.
• Coupling to photon, particularly strange channels.
• Cross sections not enough to separate broad, overlapping resonances.
• Angular distributions and polarisation observables.
• Ideal – tagged, polarized photons at CLAS
Particle Data Group star ratings
Polarisation observables
+ N → m
Linear Polarisation Glasgow, K.Livingston
Circular polarisation Nucleon recoil
polarimiter x → Y
Hyperons are “self analysing”
Transverse polarised nucleon targets
Longitudinally polarised nucleon targets
Strangeness productionGlasgow D. Ireland, K.Livingston
Single pion productionEdinburghD.Watts
Polarisation observables in pseudoscalar meson production
g target recoil Observable
4 Complex amplitudes - 16 real polarisation observables.
A complete measurement from 8 carefully chosen observables.
I. S. Barker, A. Donnachie, J. K. Storrow, Nucl. Phys. B95 347 (1975).I. S. Barker, A. Donnachie, J. K. Storrow, Nucl. Phys. B95 347 (1975).
Polarization observables - a simple example,
• Systematics of detector acceptance cancel out.
• Only need to know Plin, the degree of linear polarization.
Preliminary results - and
Craig Paterson, Glasgow
pppp
Single polarization observablesPhoton asymmetryP Recoil polarization (induced pol. along y)T Target asymmetry
Double polarization observablesOx Polarization transfer along xOz Polarization transfer along z
figure by R.Schumacher, CMU
Preliminary results - Craig Paterson, Glasgow
Photon Asymmetry
Results compared with previous results from LEPS6, 100MeV Energy bins 1550 -> 2050MeVMore bins for our data
Increase the angular coverage to backward angles
PREL
IMIN
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Preliminary results - Double polarization observable Ox
Results compared with Regge-Plus-Resonance model from Gent group
- Large Polarization transfers
- Some evidence for an important role for missing D13(1900) state
- Poor agreement at low energy
- Huge addition (> 500 points) to the database of measurements for constraining theory.
PREL
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Summary: polarisation observables, towards a complete measurement and missing resonances. • New, precision measurements on p, eta, strangeness, single and double polarization observables in progress.• Data taking with polarised target will be completed in spring 2010.• First ever “complete measurement” on K Lambda, K Sigma soon.• New, high precision range of polarisation FIX THIS TEXT
Hall A – BigBite and Neutron Electric Form FactorJ. Annand, D. Hamilton, Glasgow
Dump
TargetElectron armGen - the charge distribution inside the neutron
Neutron arm
Galster
q(2q) DSE
CQM - MillerpQCD
VMD
FSI correction not applied
Hall A• 2 High resolution spectrometers• Specific kinematics• High current > 30uA
• extras ....
Hall A @ 12GeV Super BigBite J. Annand, D. Hamilton, Glasgow
Super BigBite
• Modular spectrometer / polarimiter• Option of RICH from Hermes for Kaons• 4 A rated proposals on Form Factors
GEMs
- Magnet: 48D48 - 46 cm gap, 2.5 Tm- Solid angle is 70 msr at angle 15°- GEM chambers with 70 μm resolution- Momentum resolution is 0.5% for 5 GeV/c- Angular resolution is 0.3 mrad
Proton form factors transverse charge & current densities.
Last 50 years
Structure functions,quark longitudinalmomentum & spin distributions
Last 40 years
?
Correlated quark momentum and helicity distributions in transverse space - GPDs
Last 10 years
CLAS 12 Generalised Parton Distributions (GPDs)R.Kaiser, B.Seitz, Glasgow
CLAS 12 GPDs via DVCS
• HERMES now complete.• CLAS 12 optimised for DVCS.• Polarised targets, Asymmetry measurement
• High luminosity to reach high XB
• Glasgow GPD programme will move from HERMES -> CLAS12 (spokepsersons on 3 approved proposals)
• Example of the provision of expertise.
CLAS12 EC
TOF
Cerenkov
Torus
Drift Chambers
Cerenkov
Central Detector
Beamline IEC
Luminosity > 1035cm-2s-1G.Rosner – CLAS12 steering committeeB. Seitz, M. Hoek, uChan PMT for CTOF
Existing tagging spectrometer can’t tag beam > 6GeV
Quasi Real Photon BeamCalorimiter to tag Q2~0 electrons
Linearly polarizedparasitic
K. Livingston, D.Ireland, GlasgowD.Watts, D. Glazier, Edinburgh
With Jlab, + INFN, Italy.
GlueX exotic hybrid mesons
JPC = 0+-, 1-+, 2+-
Flux tube model
– 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.
– 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 model (JPC - exotics).
– The decay of hybrid mesons leads to complex final states.
Hall-D, GlueX ++
Lead GlassDetector
Solenoid
Electron Beam from CEBAF
Tracking
TargetCerenkovCounter
Time ofFlight
BarrelCalorimeter
Note that tagger is
80 m upstream ofdetector
Coherent BremsstrahlungPhoton Beam
• Tagger Magnet design, G. Yang, Glasgow• Coherent brem facility and diamonds – K.Livingston, G.Yang, Glasgow
• Hall D additional physics potential. High linear polarization, high intensity 2-6GeV.• Development of recoil polarimiter – D.Watts, Edinburgh.
Conclusion
• Jefferson Lab is the world’s leading facility for hardon physics.
• UK Groups (Glasgow, Edinburgh) have leading role in current programme.
• High quality measurements from Hall A, Hall B
NSAC Long Range Plan (2007) Recommendation 1 of 4 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.
• UK Groups have opportunity, at very low cost, to participate
We are here
2014
• Tagging spectrometer with high rate, good energy and timing resolution
• High precision goniometer (GWU)
• High quality, thin diamond (Glasgow)
• Tight photon beam collimation (ISU)
• Polarimetry
“A device called a goniometer tilts the diamond, much like a lady turning her hand to admire the sparkle of a new ring.” - JLAB On Target Magazine
Peak > 90% pol.
CLAS coherent bremsstrahlung facility
Photon
energ
y
P > 90%
Measurements with photon beam profile detectorD. Glazier, Glasgow
1st Measurement of 2D photon enhancement for coherent bremsstrahlung (MAMI,Mainz) paper in preparation
• Good agreement with coherent bremstrahlung calculations
• Improvements in incoherent component, collimation + multiple scattering.
• No evidence of high energy photons from quasi channeling.
• Investigation of 2D strip detector for polarimetry
Coherent peak at 300Mev, MAMI electron beam energy 855MeV
below peak coherent peak above peak
Photon Asymmetry, , extracted from cos(2) fit to azimuthal kaon distribution
Fits shown for 1 energy bin340 (20E, 17) kinematic binsAlmost full angular coverage
g8b preliminary results -
g8b preliminary results -
Results compared with previous results from GRAAL7, 50MeV Energy bins1175 -> 1475MeVGood agreement with previous results
PREL
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Results compared with previous results from LEPS6, 100MeV Energy bins1550 -> 2050MeVMore bins for our data!!!
Increase the angular coverage to backward angles
PREL
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A
RY
g8b preliminary results -
• Pair production simulations by Kharkov group
• Polarimeter built and tested at Sping8, recently tested at Jlab
e+
e-
• Polarimeter to be based on Jlab design
• Microstrip detectors, or pixel detectors (Atlas group)
• Bonn student completed 10 months exchange in Glasgow now to be full time in Bonn.
Polarimetry: from pair (e+,e-) productionH.Schmieden, Bonn
• Well described by QED, but experimentally difficult – small opening angle
PRELIMINARY
J.Santoro, CUA
Peak > 90% pol.
K.Livingston, Glasgow
Use reaction with a known photon asymmetry
• Can be high statistics
• Very good relative monitor of polarization
• Combined beam, target polarization.
• Non-indpendent – depends on specific expt
• Need very good systematics or calibration
• Awaiting MAMI polarized target and polarised photon beam in 2nd half of 2007
Polarimetry: from hadronic reactionR. Beck, Mainz -> Bonn
Recent preliminary results from JLab (g8b)
• Proton target
• Back to back charge particles in Start Counter
• Atomic or hardonic ?
• Asymmetry from ~20mins DAQ data
• Constant with E from 1.3GeV – 1.9GeV
CLAS data
SAID
High statistics. Good agreement with previous measurement.
Data set extends to photon energy up to 2.1GeV
g8b: July 2005 Polarized photon energy range: 1.3 – 2.1 GeV
Events (single charged particle in CLAS): 10 billion
preliminary results:p+n.Mike Dugger, ASU
g8b preliminary results:p’pMike Dugger, ASU
High stats for .
Good agreement with previous measurements.
Data set extends to photon energy up to 2.1GeV
First measurement of for ’
2 E bins one for coh peak at 1.9 and 2.1GeV
SAIDMAIDNakayama and Haberzettleffective lagrangian model
g8b preliminary results -
Results compared with previous results from GRAAL7, 50MeV Energy bins1175 -> 1475MeVGood agreement with previous results
PREL
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ARY
g8b preliminary results -
Ox/Oz extracted from fit to 2d asymmetry
T Target asymmetry from 2d asymmetry (not shown)
P Recoil pol. from acceptance corrected proton dist.
g8bGRAALCLAS J.W.C. McNabb, et al. (CLAS) Phys. Rev. C 69, 042201(R) (2004).
P R
ecoi
l pol
.
g13 meson photoproduction, polarized photons on LD2
n (p)ppDaria Sokhan, Edinburgh
MAIDSAID
Previous dataPREL
IMIN
A
RY
• g13a circularly polarized photons• ~2GeV, ~2.6GeV electron beam• ~2 months beamtime
• g13b linearly polarized photons• 1.3, 1.5, 1.7, 1.9, 2.1, 2.3 GeV coh peak• ~ 2months beamtime
• Single charge particle trigger• ~7kHz event rate
g13 meson photoproduction, polarized photons on LD2
p (n)nRussell Johnstone, GlasgowSee talk in Hadron Spectroscopy session
n (p)s p
Neil Hassall, Glasgow
PREL
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1st re
sults
Coscm (-0.8 - +0.8)Each plot is 50MeV photon energy bin 1050-2450MeV
p
hoto
n as
ymm
etry
Meson photoproduction with linearly and circularly polarized photons on polarized target
E02-112: γp→KY (K+Λ, K+Σ0, K0Σ+)E03-105/E04-102: γp→π0p, π+n E05-012: γp→ηpE06-013: γp→π+π-p
g9a running conditions
November 3, 2007– February 12, 2008Longitudianally polarized targetCircularly and linearly polarized photon beam 0.5-2.4 GeVTrigger: at least one charged particle in CLASTarget Pol > 80%, Relaxation time > 1600hrs – better that design goals
g9 FROST – FROzen Spin Target
butanol 12C CH2
Helicity asymmetry E Raw asymmetry
g9aFROST sample analysis of gp+n Eugene Pasyuk, ASU
•Select + applying cut on vs. p•Vertex cuts•Select missing neutron
Based on ~2% of statisticsPreliminary
butanol 12C CH2
Recoil polarimetry possibilities ?
g8b data+ p → + n with (n,p) scatter (detect +p)
Mx(p→++X)
+
np
Start counter
K.LivingstonAngle between Pn
calc and Ppmeasured
x and y (transverse) components of nucleon polarisation
n() =no(){1+A()[Pycos()–Pxsin()] - How to do this for 4 detector
Nucleon polarimeter for CB@MAMI, D. Watts, Edinburgh
Graphite
g8b preliminary results - Full lamba polarization ?
With circularly polarized photons – “fully polarized lambda”R. Bradford et al. (The CLAS Collaboration), Phys. Rev. C 75, 035205 (2007).
- Full polarization at forward angles
- Not repeated over full kinematic range
- More relations can be tested
PREL
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(P
2 + O
x2 +O
z2 )1/
2
scheduled 2010
• g8b (lin. pol. on LH2) cooking complete, analysis well developed• Photon asymmetries for p,n, , ’ , : prelim. results.• P, T Ox, Oz for , :
• g13 (lin., circ. pol on LD2) cooking in progress, analysis beginning• Some very preliminary results for photon asymmetry.
• g9 (lin, circ pol on L/T pol butanol) cooking about to begin• Circularly polarized photon beam on longitudinally polarized target
E P, Lx/Lz, Cx/Cz• Linearly polarized photon beam on longitudinally polarized target
, G, P, (Tx/Tz) Ox/Oz• Circularly polarized photon beam on transversely polarized target
T, F, P, Tx/Tz, Cx/Cz• Linearly polarized photon beam on transversely polarized target
, H, T, P, (Lx/Lz)
Upon completion of g9b for the first time we will have complete set of observables in Kaon photoproduction and nearly complete for all other mesons, which will allow model independent extraction of the amplitude for subsequent extraction of baryon resonances and their properties. (E. Pasyuk).
eg6 4He target, Bonus detector coherent meson production. (S.Stepanyan talk on Friday) scheduled 2009
HDice (A.Sandorfi, F.Klein) Polarized HD target –further extesion of polarization observables scheduled 2010
• CLAS12• Tagger will only tag up to 6GeV primary beam• Development of Quasi real photon beam (Q2~0) S.Stepanya, R.DeVita, M. Battaglieri
• Post target tagger – linearly polarized• High rates
Jefferson Lab and the 12GeV Upgrade
Nuclear Physics UK Community MeetingCosener’s House 11th & 12th June 2009
Ken Livingston, University of Glasgow
• Overview of Jefferson Lab and the 12 GeV upgade programme
• CLAS Spectrometer (Hall B)
• Polarisation observables in strangeness production
• CLAS12
• BigBite (Hall A)
• Gen - neutron electric form factor
• Super BigBite
• GlueX (Hall D)