Eugene Pasyuk DSPIN-09 Dubna, September 1-5, 2009 1 Eugene Pasyuk DSPIN-09 Dubna, September 1-5,...

Eugene Pasyuk Eugene Pasyuk DSPIN-09 DSPIN-09 Dubna, September 1-5, 2009Dubna, September 1-5, 2009 11


IntroductionIntroduction

Baryon SpectroscopyBaryon Spectroscopy

What's in Hall B? What's in Hall B?

CLASCLAS

Tagged polarized photon beamsTagged polarized photon beams

FROzen Spin TargetFROzen Spin Target

Glimpse of the dataGlimpse of the data

OutlookOutlook

SummarySummary



N*N*


ExperimentExperimentcross section, cross section,

spin observablesspin observables

ExperimentExperimentcross section, cross section,

spin observablesspin observables

TheoryTheoryLQCD,LQCD,

quark models,quark models,QCD sum rulesQCD sum rules,

…

TheoryTheoryLQCD,LQCD,

quark models,quark models,QCD sum rulesQCD sum rules,

…

Reaction TheoryReaction Theorydynamical frameworksdynamical frameworks

Reaction TheoryReaction Theorydynamical frameworksdynamical frameworks

Amplitude analysisAmplitude analysis→→multipole amplitudesmultipole amplitudes

→→phase shiftsphase shifts

Amplitude analysisAmplitude analysis→→multipole amplitudesmultipole amplitudes

→→phase shiftsphase shifts

σ,dσ/dΩ,Σ,P,Tσ,dσ/dΩ,Σ,P,T

(beam-target)(beam-target) E,F,G,H, E,F,G,H,(beam-recoil)(beam-recoil) C Cxx,C,Czz,O,Oxx,O,Ozz,,(target-recoil)(target-recoil) L Lxx,L,Lzz, T, Txx,T,Tzz,,

Coupled channels:Coupled channels: resonance parameter resonance parameter

extractionextraction


I. S. Barker, A. Donnachie, J. K. Storrow, Nucl. Phys. B95I. S. Barker, A. Donnachie, J. K. Storrow, Nucl. Phys. B95,, 347 347 (1975).(1975).I. S. Barker, A. Donnachie, J. K. Storrow, Nucl. Phys. B95I. S. Barker, A. Donnachie, J. K. Storrow, Nucl. Phys. B95,, 347 347 (1975).(1975).

44 Complex amplitudes - Complex amplitudes - 1616 real polarization observables. real polarization observables.A A complete measurement fromcomplete measurement from 88 carefully chosen carefully chosen observablesobservables. .


Emax ~ 6 GeVEmax ~ 6 GeVImax ~ 200 Imax ~ 200 AADuty Factor ~ 100%Duty Factor ~ 100%E/E ~ 2.5 10-5E/E ~ 2.5 10-5Beam P Beam P ≥≥ 80% 80%EE ~ 0.5-5.8 GeV ~ 0.5-5.8 GeV taggedtagged

Hall-BHall-BHall-BHall-B


Torus magnetTorus magnet6 superconducting coils6 superconducting coils

Gas Cherenkov countersGas Cherenkov counterse/e/ separation, 256 PMTs separation, 256 PMTs

Time-of-flight countersTime-of-flight countersplastic scintillators, 684 plastic scintillators, 684 photomultipliersphotomultipliers

Drift chambersDrift chambers35,000 cells35,000 cells

Liquid DLiquid D2 2 (H(H22) target +) target +

start counter; e mini-start counter; e mini-torustorus

Electromagnetic calorimetersElectromagnetic calorimetersLead/scintillator, 1296 photomultipliersLead/scintillator, 1296 photomultipliers


61 backing counters

Jefferson Lab Hall B Jefferson Lab Hall B photon tagger:photon tagger:

EE = 20-95% of E = 20-95% of E00

EE up to ~5.8 GeV up to ~5.8 GeV

dE/E ~10dE/E ~10-3-3 of E of E00


Circularly polarized beam Circularly polarized beam produced by longitudinally produced by longitudinally polarized electronspolarized electrons

CEBAF electron beam CEBAF electron beam polarization >85%polarization >85%

tagged flux ~ 50 - 100MHz (for k>0.5 Etagged flux ~ 50 - 100MHz (for k>0.5 E00

2

2

344

4

kk

kkPP e


Linearly polarized photons: coherent Linearly polarized photons: coherent bremsstrahlung on oriented diamond crystalbremsstrahlung on oriented diamond crystal


existing dynamically polarized existing dynamically polarized NHNH33, , NDND

3 3 targettarget

polarizing magnet 5.1 T polarizing magnet 5.1 T Helmholtz coilsHelmholtz coils

reduces acceptance to θ<65reduces acceptance to θ<65oo





4 layers of superconductive wire4 layers of superconductive wireField 0.54 TField 0.54 TNo visible losses of polarization while doing spin No visible losses of polarization while doing spin rotation →↑rotation →↑


butanolbutanol

1212CCCHCH

22


Base Base temperaturetemperature

Cooling powerCooling power

PolarizationPolarization

1/e relaxation 1/e relaxation timetime

Design goalDesign goal

<50 mK<50 mK

1010W (Frozen)W (Frozen)mW (Polarizing) 20mW (Polarizing) 20

80%80%

hours 500hours 500

mK 50>mK 50>

1010W (Frozen)W (Frozen)20 mW (Polarizing)20 mW (Polarizing)

80%80%

500 hours500 hours

28 mK w/o beam28 mK w/o beam30 mK with beam30 mK with beam

800 800 W @50 mKW @50 mK10 mW @ 100 mK10 mW @ 100 mK60 mW @300 mK60 mW @300 mK

+82%+82%-85%-85%

2800 hours (+Pol)2800 hours (+Pol)hours (-Pol 1600hours (-Pol 1600((

mK w/o beam 28mK w/o beam 28mK with beam 30mK with beam 30

800 800W @50 mKW @50 mKmW @ 100 mK 10mW @ 100 mK 10mW @300 mK 60mW @300 mK 60

82%+82%+85%-85%-

hours (+Pol) 2800hours (+Pol) 28001600 hours (-Pol1600 hours (-Pol))

ResultResult

Excellent reliability! Continuously running October 29 – February Excellent reliability! Continuously running October 29 – February 12. 12.

Entire repolarization procedure takes under 6 hoursEntire repolarization procedure takes under 6 hoursTake data for 5-6 daysTake data for 5-6 days



g1g1: : EE = 0.5 – 2.9 GeV circularly polarized beam = 0.5 – 2.9 GeV circularly polarized beam

γγp→πp→π00p, πp, π++nn dd/d/d

γγp→ηpp→ηp dd/d/d

γγp→η'p p→η'p dd/d/d

γγp→KY (Kp→KY (K++Λ, KΛ, K++ΣΣ00, K, K00ΣΣ++) ) dd/d/d, , P, CP, C

x'x'/C/Cz'z'

γγp→πp→π++ππ--pp


g8g8: : EE = 0.9 – 2.1 GeV Linearly polarized = 0.9 – 2.1 GeV Linearly polarized

γγp→πp→π00p, πp, π++nn

γγp→ηp p→ηp

γγp→η'p p→η'p

γγp→KY (Kp→KY (K++Λ, KΛ, K++ΣΣ00, K, K00ΣΣ++) ) , , P, T, OP, T, O

xx/O/Ozz


R. Schumacher


Nikanov et al’.’s refit of Bonn-Gachina multi-coupled-channel isobar modelmix includes: S11 wave, P13(1720), P13(1900), P11(1840)K+Σ0cross sections also better described with P13(1900)Promote this “missing”resonance from ** to **** status.P13(1900) is found in qqq quark models, but not in quark-diquark models

R. Schumacher


2 2 2x zR P C Cº 2 2 2x zR P C Cº

The The appears 100% polarized when created with a fully appears 100% polarized when created with a fully polarized beam.polarized beam.

R. Schumacher


R. Schumacher

Energy and angle averages are consistent with unity.

No such effect with linearly polarized photons.

No such effect for

2 2 2x zR P C Cº

1 .0 1 0 .0 1R ±

No model predicted this CLAS result.


Polarized beam still is not enough, we Polarized beam still is not enough, we need polarized target!need polarized target!

E02-112:E02-112: γp→KY γp→KY (K(K++ΛΛ, K, K++ΣΣ00, K, K00ΣΣ++))

E03-105/E04-102: E03-105/E04-102: γp→πγp→π00p, πp, π++nn

E05-012:E05-012: γp→ηpγp→ηp

E06-013:E06-013: γp→πγp→π++ππ--pp

We can do “Complete experiment” for We can do “Complete experiment” for KY! KY!


November 3, 2007– February 12, 2008November 3, 2007– February 12, 2008

Longitudinally polarized targetLongitudinally polarized target

Circularly and linearly polarized photon beam 0.5-Circularly and linearly polarized photon beam 0.5-2.4 GeV2.4 GeV

Trigger: at least one charged particle in CLASTrigger: at least one charged particle in CLAS


Helicity asymmetry Helicity asymmetry EE

Raw asymmetryRaw asymmetry


Circularly polarized photon beam on longitudinally Circularly polarized photon beam on longitudinally polarized targetpolarized target

E, E, PP, Lx/Lz, , Lx/Lz, Cx/CzCx/Cz

Linearly polarized photon beam on longitudinally polarized Linearly polarized photon beam on longitudinally polarized targettarget

, G, , G, PP, (Tx/Tz) , (Tx/Tz) Ox/OzOx/Oz

Circularly polarized photon beam on transversely polarized Circularly polarized photon beam on transversely polarized targettarget

T, F, T, F, PP,, Tx/Tz, Tx/Tz, Cx/CzCx/Cz

Linearly polarized photon beam on transversely polarized Linearly polarized photon beam on transversely polarized targettarget

, H, T, P, , H, T, P, (Lx/Lz) (Lx/Lz)

Complete

Scheduled fo

r 2010

Scheduled fo

r 2010


To reveal isospin structure it is essential To reveal isospin structure it is essential to do measurements on the neutronto do measurements on the neutron

G13 running period accumulated large G13 running period accumulated large dataset with circularly an linearly dataset with circularly an linearly polarized photons on liquid deuterium polarized photons on liquid deuterium unpolarized targetunpolarized target

The data are being analizedThe data are being analized


A. Sandorfi


A. Sandorfi


New addition in Hall B of Frozen Spin Target, with both, New addition in Hall B of Frozen Spin Target, with both, longitudinal and transverse polarization significantly advances longitudinal and transverse polarization significantly advances our experimental capabilities.our experimental capabilities.

It is possible to perform It is possible to perform completecomplete experiment of KY experiment of KY photoproduction and photoproduction and nearly complete nearly complete for other final states.for other final states.

Entire program is more than just a sum of several experiments, Entire program is more than just a sum of several experiments, observables for all final states are measured simultaneously observables for all final states are measured simultaneously under the same experimental conditions and have the same under the same experimental conditions and have the same systematic uncertainties. systematic uncertainties.

It can be considered as “It can be considered as “coupled channel experimentcoupled channel experiment” ultimately ” ultimately providing data for providing data for coupled channel analysis coupled channel analysis and extraction of and extraction of parameters of baryon resonances.parameters of baryon resonances.

Supply data EBAC – Excited Baryon Analysis Center at JLABSupply data EBAC – Excited Baryon Analysis Center at JLAB

Experiments with HD-Ice target are in preparationExperiments with HD-Ice target are in preparation


The CLAS Collaboration

Idaho State University, Pocatello, IdahoINFN, Laboratori Nazionali di Frascati, Frascati, Italy

INFN, Sezione di Genova, Genova, ItalyInstitut de Physique Nucléaire, Orsay, France

ITEP, Moscow, RussiaJames Madison University, Harrisonburg, VAKyungpook University, Daegu, South KoreaUniversity of Massachusetts, Amherst, MA Moscow State University, Moscow, RussiaUniversity of New Hampshire, Durham, NH

Norfolk State University, Norfolk, VAOhio University, Athens, OH

Old Dominion University, Norfolk, VA

Arizona State University, Tempe, AZUniversity of California, Los Angeles, CACalifornia State University, Dominguez Hills, CACarnegie Mellon University, Pittsburgh, PACatholic University of AmericaCEA-Saclay, Gif-sur-Yvette, FranceChristopher Newport University, Newport News, VAUniversity of Connecticut, Storrs, CTEdinburgh University, Edinburgh, UKFlorida International University, Miami, FLFlorida State University, Tallahassee, FLGeorge Washington University, Washington, DCUniversity of Glasgow, Glasgow, UK

Rensselaer Polytechnic Institute, Troy, NYRice University, Houston, TX

University of Richmond, Richmond, VAUniversity of South Carolina, Columbia, SC

Thomas Jefferson National Accelerator Facility, Newport News, VA

Union College, Schenectady, NYVirginia Polytechnic Institute, Blacksburg, VA

University of Virginia, Charlottesville, VACollege of William and Mary, Williamsburg, VAYerevan Institute of Physics, Yerevan, Armenia

Brazil, Germany, Morocco and Ukraine, as well as other institutions in France and in the USA,

have individuals or groups involved with CLAS, but with no formal collaboration at this stage.

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Eugene Pasyuk DSPIN-09 Dubna, September 1-5, 2009 1 Eugene Pasyuk DSPIN-09 Dubna, September 1-5,...

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