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CLAS 3 rd Euroworkshop Glasgow, UK, June 20-22, 2013. Status N* photoproduction with CLAS. Eugene Pasyuk Jefferson Lab. Resonance status for N * and Δ *. Nearly half the states have only fair or poor evidence! Most states need more work to learn details Are there missing states?.

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Status n photoproduction with clas

CLAS 3rdEuroworkshop

Glasgow, UK, June 20-22, 2013

Status N* photoproductionwith CLAS

Eugene Pasyuk

Jefferson Lab


Resonance status for N* and Δ*

  • Nearly half the states have only fair or poor evidence!

  • Most states need more work to learn details

  • Are there missing states?

E. Pasyuk CLAS 3rd Euroworkshop Glasgow, UK, June 20-22, 2013


Baryon resonance spectrum
Baryon Resonance Spectrum

N*

S. Capstik and W. Roberts

R.G. Edwards et al. Phys. Rev. D84 074508 (2011)

Lattice QCD

Mass(π) = 396 MeV

Masses, widths, and coupling constants not well known for many resonances

Most models predict more resonance states than observed

E. Pasyuk CLAS 3rd Euroworkshop Glasgow, UK, June 20-22, 2013


From the experiment to theory
From the Experiment to Theory

Experiment

cross section,

spin observables

(single) dσ/dΩ,Σ,P,T

(beam-target) E,F,G,H,

(beam-recoil)Cx,Cz,Ox,Oz,

(target-recoil)Lx,Lz, Tx,Tz,

Amplitude analysis

→multipole amplitudes

→phase shifts

Reaction Theory

dynamical frameworks

Theory

LQCD,

quark models,

QCD sum rules,

E. Pasyuk CLAS 3rd Euroworkshop Glasgow, UK, June 20-22, 2013


Polarization observables in pseudoscalar meson production
Polarization observables in pseudoscalar meson production

4Complex amplitudes: 16real polarization observables.

Complete measurement from 8carefully chosen observables.

πN has large cross section but in KY recoil is self-analysing

πN

KY

recoil targγ

γ targrecoil

☻☻☻

☻☻☻

☻☻☻

☻☻☻

☻☻☻

☻☻☻

☻☻☻

☻☻☻

☻☻☻

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

Complete, and

over-determined

circ polarized photons

longitudinally polarized target

linearly polarized photons

transversely polarized target

E. Pasyuk CLAS 3rd Euroworkshop Glasgow, UK, June 20-22, 2013


Cebaf large acceptance spectrometer 1997 2012
CEBAF Large Acceptance Spectrometer 1997-2012

Torus magnet

6 superconducting coils

Electromagnetic calorimeters

Lead/scintillator, 1296 photomultipliers

target + start counter

Drift chambers

35,000 cells

Time-of-flight counters

plastic scintillators, 684 photomultipliers

Gas Cherenkov counters

e/ separation, 256 PMTs

E. Pasyuk CLAS 3rd Euroworkshop Glasgow, UK, June 20-22, 2013


12/18/2012

E. Pasyuk CLAS 3rd Euroworkshop Glasgow, UK, June 20-22, 2013



Polarized pohoton beam
Polarized June 20-22, 2013 pohoton beam

Circular polarization from 100% polarized electron beam

Circular polarization

H. Olsen and L.C. Maximon, Phys. Rev. 114, 887 (1959)

Circularly polarized beam produced by longitudinally polarized electrons

Linearly polarized photons: coherent bremsstrahlung on oriented diamond crystal

E. Pasyuk CLAS 3rd Euroworkshop Glasgow, UK, June 20-22, 2013


Frost
FROST June 20-22, 2013

E. Pasyuk CLAS 3rd Euroworkshop Glasgow, UK, June 20-22, 2013


Hdice polarized target
HDIce June 20-22, 2013 polarized target

Polarized at very high magnetic field and very low temperature

Transferred to in-beam cryostat

Spin can be moved between H and D with RF transitions

All material can be polarized with small background

E. Pasyuk CLAS 3rd Euroworkshop Glasgow, UK, June 20-22, 2013


What we measure with clas
What we measure with CLAS June 20-22, 2013

γp→π0p, π+n

γp→ηp

γp→η’p

γp→KY (K+Λ, K+Σ0, K0Σ+)

γp→π+π-p ωp, ρp, ϕp

….

γn→π-p

γn→π+π-n

γn→Σ-K+ , ΛK0

…..

E. Pasyuk CLAS 3rd Euroworkshop Glasgow, UK, June 20-22, 2013


Single pion production
Single pion production June 20-22, 2013

E. Pasyuk CLAS 3rd Euroworkshop Glasgow, UK, June 20-22, 2013


For p n
Σ June 20-22, 2013 for γp →nπ+

g8b

DU12

CM12

MAID

BbGa

60

60

0

0

120

120

M. Dugger et al.

Paper under collaboration review

E. Pasyuk CLAS 3rd Euroworkshop Glasgow, UK, June 20-22, 2013


For p p 0
Σ June 20-22, 2013 for γ p → p π0

g8b

DU12

CM12

MAID

BbGa

M. Dugger et al.

Paper under collaboration review

E. Pasyuk CLAS 3rd Euroworkshop Glasgow, UK, June 20-22, 2013


Changes in couplings
Changes in couplings June 20-22, 2013

Those are both **** states!

E. Pasyuk CLAS 3rd Euroworkshop Glasgow, UK, June 20-22, 2013


E June 20-22, 2013 for γ p → p π0

g9a

(new)

  • Early stage results

  • Predictions agree better at lower energies

M. Dugger et al.

E. Pasyuk CLAS 3rd Euroworkshop Glasgow, UK, June 20-22, 2013


E June 20-22, 2013 for γ p → n π+

g9a

SAID

SAID (new fit)

MAID

W = 1.25 GeV

W = 1.27 GeV

W = 1.29 GeV

W = 1.31 GeV

W = 1.33 GeV

W = 1.35 GeV

PRELIMINARY

PRELIMINARY

PRELIMINARY

PRELIMINARY

PRELIMINARY

PRELIMINARY

W = 1.45 GeV

W = 1.47 GeV

W = 1.37 GeV

W = 1.39 GeV

W = 1.41 GeV

W = 1.43 GeV

Predictions worse at higher energies above 1.7 GeV

PRELIMINARY

PRELIMINARY

PRELIMINARY

PRELIMINARY

PRELIMINARY

PRELIMINARY

W = 1.51 GeV

W = 1.49 GeV

W = 1.53 GeV

W = 1.55 GeV

W = 1.57 GeV

W = 1.59 GeV

PRELIMINARY

PRELIMINARY

PRELIMINARY

PRELIMINARY

PRELIMINARY

PRELIMINARY

PRELIMINARY

PRELIMINARY

PRELIMINARY

PRELIMINARY

PRELIMINARY

PRELIMINARY

W = 1.63 GeV

W = 1.61 GeV

W = 1.69 GeV

W = 1.71 GeV

W = 1.65 GeV

W = 1.67 GeV

W=1.73 GeV

W = 1.9 GeV

W = 1.75 GeV

W = 1.77 GeV

W = 1.81 GeV

W = 1.83 GeV

PRELIMINARY

W = 1.73 GeV

PRELIMINARY

PRELIMINARY

PRELIMINARY

PRELIMINARY

PRELIMINARY

W = 1.94 GeV

W = 1.98 GeV

W = 2.02 GeV

PRELIMINARY

PRELIMINARY

PRELIMINARY

W = 2.07 GeV

W = 2.13 GeV

W = 2.19 GeV

PRELIMINARY

PRELIMINARY

PRELIMINARY

Cos(θπc.m.)

S. Strauch

Analysis note is being written

E. Pasyuk CLAS 3rd Euroworkshop Glasgow, UK, June 20-22, 2013


T June 20-22, 2013 for γ p → n π+

g9b

(new)

(new)

(new)

M. Dugger et al.

E. Pasyuk CLAS 3rd Euroworkshop Glasgow, UK, June 20-22, 2013


F June 20-22, 2013 for γ p → n π+

g9b

(new)

(new)

  • Agreement with predictions get much worse at higher energies

  • SAID13 are predictions based on preliminary fits to CLAS pion Σ measurements

(new)

M. Dugger et al.

E. Pasyuk CLAS 3rd Euroworkshop Glasgow, UK, June 20-22, 2013


For n p
Σ June 20-22, 2013 forγ n → p π-

g13

  • preliminary

D. Sokhan

Curve - SAID

Red GRAAL

Magenta and Blue - Erevan

9 out of 40 angular bins are shown

Bins 0.04 in cos and 20 MeV in W

E. Pasyuk CLAS 3rd Euroworkshop Glasgow, UK, June 20-22, 2013


E for n p p p
E June 20-22, 2013 forγn(p) →pπ-(p)

g14

T. Kagea

E. Pasyuk CLAS 3rd Euroworkshop Glasgow, UK, June 20-22, 2013


Photoproduction
η June 20-22, 2013 photoproduction

E. Pasyuk CLAS 3rd Euroworkshop Glasgow, UK, June 20-22, 2013


Σ June 20-22, 2013 forγp →pη

g8b

PRELIMINARY

PRELIMINARY

PRELIMINARY

PRELIMINARY

PRELIMINARY

PRELIMINARY

PRELIMINARY

PRELIMINARY

PRELIMINARY

PRELIMINARY

PRELIMINARY

PRELIMINARY

PRELIMINARY

  • preliminary

PRELIMINARY

PRELIMINARY

PRELIMINARY

PRELIMINARY

PRELIMINARY

PRELIMINARY

PRELIMINARY

SAID

MAID

PRELIMINARY

PRELIMINARY

PRELIMINARY

PRELIMINARY

PRELIMINARY

PRELIMINARY

PRELIMINARY

PRELIMINARY

PRELIMINARY

PRELIMINARY

P. Collins

Analysis under working group review

E. Pasyuk CLAS 3rd Euroworkshop Glasgow, UK, June 20-22, 2013


E for for p p
E for June 20-22, 2013 forγp →pη

g9a

I. Senderovich

E. Pasyuk CLAS 3rd Euroworkshop Glasgow, UK, June 20-22, 2013


G for for p p
G June 20-22, 2013 forforγp →pη

g9a

I. Senderovich

E. Pasyuk CLAS 3rd Euroworkshop Glasgow, UK, June 20-22, 2013


T for for p p
T June 20-22, 2013 forforγp → pη

R. Tucker

E. Pasyuk CLAS 3rd Euroworkshop Glasgow, UK, June 20-22, 2013


F for for p p
F June 20-22, 2013 forforγp → pη

R. Tucker

E. Pasyuk CLAS 3rd Euroworkshop Glasgow, UK, June 20-22, 2013


Ky production
KY production June 20-22, 2013

E. Pasyuk CLAS 3rd Euroworkshop Glasgow, UK, June 20-22, 2013


Σ , O June 20-22, 2013 x , Oz for γp→ K+Λ

g8b

D. G. Ireland, K. Livingston, B. McKinnon, C. A. Paterson

E. Pasyuk CLAS 3rd Euroworkshop Glasgow, UK, June 20-22, 2013


Σ , O June 20-22, 2013 x , Oz for γp→ K+Σ0

g8b

D. G. Ireland, K. Livingston, B. McKinnon, C. A. Paterson

E. Pasyuk CLAS 3rd Euroworkshop Glasgow, UK, June 20-22, 2013


T June 20-22, 2013 for γp→ K+Λ and γ p → K+Σ0

g8b

Due to the self-analyzing nature of the , determine many observables using only a linearly polarized beam

Direct measurements of T

A4 – N. Walford

D. G. Ireland, K. Livingston, B. McKinnon, C. A. Paterson

E. Pasyuk CLAS 3rd Euroworkshop Glasgow, UK, June 20-22, 2013


T for p k
T June 20-22, 2013 for γp→K+Λ

g9b

W=1725 MeV

Eγ=1117 MeV

W=1675 MeV

Eγ=1027 MeV

W=1775 MeV

Eγ=1210 MeV

W=1825 MeV

Eγ=1306 MeV

★-CLAS

BnGa

kaonMAID

W=1975 MeV

Eγ=1610 MeV

W=2025 MeV

Eγ=1717 MeV

W=1875 MeV

Eγ=1405 MeV

W=1925 MeV

Eγ=1506 MeV

  • preliminary

W=2175 MeV

Eγ=2053 MeV

W=2275 MeV

Eγ=2290 MeV

W=2225 MeV

Eγ=2170 MeV

W=2125 MeV

Eγ=1938 MeV

N. Walford

E. Pasyuk CLAS 3rd Euroworkshop Glasgow, UK, June 20-22, 2013


T for p k 0
T June 20-22, 2013 for γp → K+Σ0

g9b

★-CLAS

BnGa

kaonMAID

W=1725 MeV

Eγ=1117 MeV

W=1775 MeV

Eγ=1210 MeV

W=1875 MeV

Eγ=1405 MeV

W=1825 MeV

Eγ=1306 MeV

  • preliminary

W=1975 MeV

Eγ=1610 MeV

W=2025 MeV

Eγ=1717 MeV

W=2075 MeV

Eγ=1826 MeV

W=1925 MeV

Eγ=1506 MeV

W=2125 MeV

Eγ=1938 MeV

W=2175 MeV

Eγ=2053 MeV

W=2225 MeV

Eγ=2170 MeV

W=2275 MeV

Eγ=2290 MeV

N. Walford

E. Pasyuk CLAS 3rd Euroworkshop Glasgow, UK, June 20-22, 2013


F for p k
F June 20-22, 2013 for γp→K+Λ

g9b

★-CLAS

BnGa

kaonMAID

  • preliminary

N. Walford

E. Pasyuk CLAS 3rd Euroworkshop Glasgow, UK, June 20-22, 2013


P p photoproduction
p June 20-22, 2013 +p-photoproduction

E. Pasyuk CLAS 3rd Euroworkshop Glasgow, UK, June 20-22, 2013


Photoproduction of p states
Photoproduction June 20-22, 2013 of π+π-p states

  • Dominates photoproduction cross section for W >1.6 GeV

  • 64 observables

  • 28 independent relations related to helicity amplitude magnitudes

  • 21 independent relations related to helicity amplitude phases

  • Results in 15 independent numbers

Could be used for search of resonances that decay into other resonances

E. Pasyuk CLAS 3rd Euroworkshop Glasgow, UK, June 20-22, 2013


Cross section for p p
Cross section for June 20-22, 2013 γp →pπ+π-

E. Pasyuk CLAS 3rd Euroworkshop Glasgow, UK, June 20-22, 2013


I s for p
I June 20-22, 2013 S for pπ+π-

g8b

Linearly polarized photons, unpolarized target

E=1900-1950 MeV W=2120 MeV

Charles Hanretty

One of 20 energy bins

E. Pasyuk CLAS 3rd Euroworkshop Glasgow, UK, June 20-22, 2013


I for p
I June 20-22, 2013 for pπ+π-

g9a

W. Roberts and T. Oed,PRC 71, 055201 (2005)

S. Strauch et al., PRL. 95, 162003 (2005)

S. Park

A. Fix and H. Arenhovel,EPJA 25, 115 (2005)

E. Pasyuk CLAS 3rd Euroworkshop Glasgow, UK, June 20-22, 2013


P z for p
P June 20-22, 2013 zfor pπ+π-

g9a

W. Roberts and T. Oed,PRC 71, 055201 (2005)

S. Park

A. Fix and H. Arenhovel,EPJA 25, 115 (2005)

E. Pasyuk CLAS 3rd Euroworkshop Glasgow, UK, June 20-22, 2013


P z for p1
P June 20-22, 2013 zfor pπ+π-

g9a

W. Roberts and T. Oed,PRC 71, 055201 (2005)

S. Park

A. Fix and H. Arenhovel,EPJA 25, 115 (2005)

E. Pasyuk CLAS 3rd Euroworkshop Glasgow, UK, June 20-22, 2013


Comparison with model p c z
Comparison with model: June 20-22, 2013 Pcz

g9a

preliminary

A. Fix and H. Arenhovel,EPJA 25, 115 (2005)

Y. Mao

E. Pasyuk CLAS 3rd Euroworkshop Glasgow, UK, June 20-22, 2013


Comparison with model p s z
Comparison with model: June 20-22, 2013 Psz

g9a

preliminary

A. Fix and H. Arenhovel,EPJA 25, 115 (2005)

Y. Mao

E. Pasyuk CLAS 3rd Euroworkshop Glasgow, UK, June 20-22, 2013


Summary of meson photoproduction
Summary of meson June 20-22, 2013 photoproduction

✔ -published✔- acquired

E. Pasyuk CLAS 3rd Euroworkshop Glasgow, UK, June 20-22, 2013


Summary
Summary June 20-22, 2013

Data collection with proton and deuteron targets is complete

“complete (or nearly complete) measurement” in pseudoscalar meson photoproductionis in the can

In many cases these are the first measurements.

In most cases model predictions do not agree with the data at higher energies

Phenomenological and theoretical analyses will have to deal with tenths of thousands of data points for various observables in different final states.

Setting up close collaboration with Bonn-Gatchina group.

E. Pasyuk CLAS 3rd Euroworkshop Glasgow, UK, June 20-22, 2013


Extras
Extras June 20-22, 2013

E. Pasyuk CLAS 3rd Euroworkshop Glasgow, UK, June 20-22, 2013


Polarization observables in pseudoscalar meson production1
Polarization observables in pseudoscalar meson production June 20-22, 2013

E. Pasyuk CLAS 3rd Euroworkshop Glasgow, UK, June 20-22, 2013


G14 e06 101 polarized gamma beams on polarized hd

• Circular and Linear polarized photons June 20-22, 2013

• flux up to 108 s-1 tagged (low bkg)

• Longitudinally polarized solid HD

• P(D) ~ 22%; lifetimes ~ 2 yr

• Nov/11 – May/12: 14 billion triggers

g14 – E06-101: polarized gamma beams on polarized HD



R values for the
R Values for the June 20-22, 2013 

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

E. Pasyuk CLAS 3rd Euroworkshop Glasgow, UK, June 20-22, 2013


Average r values
Average R values June 20-22, 2013

Energy and angle averages are consistent with unity.

No model predicted this CLAS result.

E. Pasyuk CLAS 3rd Euroworkshop Glasgow, UK, June 20-22, 2013


Model of effective June 20-22, 2013 Lagrangian approach

Diagrams of N* for the reaction γN → ππN

  • Other decays:

  • N-Born terms

  • Δ-Born terms

  • About the model:

  • Calculates diff-cross section by using transition amplitudes

  • Amplitudes are determined by all the double-pion diagrams

  • The diagrams above show the decay from N* resonances.

  • Include resonances:

53

E. Pasyuk CLAS 3rd Euroworkshop Glasgow, UK, June 20-22, 2013


Examples of 2-fold differential June 20-22, 2013 g p → p  cross sections

2-fold cross sections within the CLAS acceptance.

Nine one-fold and 18 two-fold differential cross sections have become available for the first time in W-bins of 25 MeV width.


One-fold differential June 20-22, 2013 g p → p  cross sections

Blue dots: experimental data within the CLAS acceptance

Black dots: accounting for the contributions from inefficient areas employing phase space approximation

Red dots: extrapolating cross sections into inefficient areaswithin the framework ofthe JM model

Two approaches for cross section extrapolation provided close results


P k cross section and p
γ June 20-22, 2013 p→K+Λ: cross section and P

g11: W=1.7 – 2.8 GeV

(unpolarized beam & target)

recoil polarization P

excitation function

M.E. McCracken et al., PRC 81, 025201 (2010)

E. Pasyuk CLAS 3rd Euroworkshop Glasgow, UK, June 20-22, 2013


P k cx cz
γ June 20-22, 2013 p→K+Λ: Cx/Cz

Bradford et al. PRC 75, 035205 (2007),

E. Pasyuk CLAS 3rd Euroworkshop Glasgow, UK, June 20-22, 2013


Comparison with other measurements
Comparison with other measurements June 20-22, 2013

E. Pasyuk CLAS 3rd Euroworkshop Glasgow, UK, June 20-22, 2013


Comparison with other measurements1
Comparison with other measurements June 20-22, 2013

LEPS

LEPS

CLAS g8

CLAS g8

GRAAL

GRAAL

E. Pasyuk CLAS 3rd Euroworkshop Glasgow, UK, June 20-22, 2013


Beam asymmetry comparison
Beam Asymmetry Comparison June 20-22, 2013

E. Pasyuk CLAS 3rd Euroworkshop Glasgow, UK, June 20-22, 2013


Beam asymmetry comparison1
Beam Asymmetry Comparison June 20-22, 2013

E. Pasyuk CLAS 3rd Euroworkshop Glasgow, UK, June 20-22, 2013


Beam asymmetry comparison2
Beam Asymmetry Comparison June 20-22, 2013

E. Pasyuk CLAS 3rd Euroworkshop Glasgow, UK, June 20-22, 2013


Beam recoil comparison
Beam-Recoil Comparison June 20-22, 2013

E. Pasyuk CLAS 3rd Euroworkshop Glasgow, UK, June 20-22, 2013


Beam asymmetry comparison3
Beam Asymmetry Comparison June 20-22, 2013

E. Pasyuk CLAS 3rd Euroworkshop Glasgow, UK, June 20-22, 2013


Beam Asymmetry June 20-22, 2013

E. Pasyuk CLAS 3rd Euroworkshop Glasgow, UK, June 20-22, 2013


Target Asymmetry June 20-22, 2013

E. Pasyuk CLAS 3rd Euroworkshop Glasgow, UK, June 20-22, 2013


Beam-Recoil, Ox June 20-22, 2013

E. Pasyuk CLAS 3rd Euroworkshop Glasgow, UK, June 20-22, 2013


Beam-Recoil, Oz June 20-22, 2013

E. Pasyuk CLAS 3rd Euroworkshop Glasgow, UK, June 20-22, 2013


Beam Asymmetry June 20-22, 2013

E. Pasyuk CLAS 3rd Euroworkshop Glasgow, UK, June 20-22, 2013


Target Asymmetry June 20-22, 2013

E. Pasyuk CLAS 3rd Euroworkshop Glasgow, UK, June 20-22, 2013


Beam-Recoil, Ox June 20-22, 2013

E. Pasyuk CLAS 3rd Euroworkshop Glasgow, UK, June 20-22, 2013


Beam-Recoil, Oz June 20-22, 2013

E. Pasyuk CLAS 3rd Euroworkshop Glasgow, UK, June 20-22, 2013


For p p 01
Σ June 20-22, 2013 for γ p → p π0

DU12

CM12

MAID

BbGa

M. Dugger et al.

E. Pasyuk CLAS 3rd Euroworkshop Glasgow, UK, June 20-22, 2013


W=1675 MeV June 20-22, 2013

Eγ=1027 MeV

W=1725 MeV

Eγ=1117 MeV

W=1775 MeV

Eγ=1210 MeV

W=1825 MeV

Eγ=1306 MeV

W=1875 MeV

Eγ=1405 MeV

W=1925 MeV

Eγ=1506 MeV

W=1975 MeV

Eγ=1610 MeV

W=2025 MeV

Eγ=1717 MeV

W=2225 MeV

Eγ=2170 MeV

W=2175 MeV

Eγ=2053 MeV

W=2275 MeV

Eγ=2290 MeV

W=2125 MeV

Eγ=1938 MeV

W=2075 MeV

Eγ=1826 MeV

E. Pasyuk CLAS 3rd Euroworkshop Glasgow, UK, June 20-22, 2013


T for p k1
T June 20-22, 2013 for γ p → K+Λ

N. Walford

E. Pasyuk CLAS 3rd Euroworkshop Glasgow, UK, June 20-22, 2013


Integrated cross sections for p p
Integrated June 20-22, 2013 cross sections for γp → p π+π-

Preliminary results: integrated cross section at W from 1.6 to 2.8 GeV

JLAB g11a

accept. corr. applied

SAPHIR(2005)&ABBHHM(1969)

JLAB g11a within CLAS acceptance

Systematic errors from accept. corr. procedure ~8-20%

E .Golovach

E. Pasyuk CLAS 3rd Euroworkshop Glasgow, UK, June 20-22, 2013


Differential cross sections for p p
Differential cross sections for June 20-22, 2013 γp → pπ+π-

Blues dots:

Measured cross sections within the CLAS acceptance.

Blue line:

JM model*prediction within the CLAS acceptance.

Black line:

JM model results for 100% acceptance.

Black dots:

Estimated cross sections when the contribution from inefficient area was obtained employing phase space approximation.

*Mokeev et al.

PRC 80 (2009) 045212

E .Golovach

E. Pasyuk CLAS 3rd Euroworkshop Glasgow, UK, June 20-22, 2013


Differential cross sections for p p1
Differential cross sections for June 20-22, 2013 γp → pπ+π-

Blues dots:

Measured cross sections within the CLAS acceptance.

Black dots:

Estimated cross sections when the contribution from inefficient area was obtained employing phase space approximation.

E .Golovach

E. Pasyuk CLAS 3rd Euroworkshop Glasgow, UK, June 20-22, 2013


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