photons off transversely polarized protons (g9b-FROST) Lelia - - PowerPoint PPT Presentation

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photons off transversely polarized protons (g9b-FROST) Lelia - - PowerPoint PPT Presentation

Polarization observables in double charged pion photo-production with circularly polarized photons off transversely polarized protons (g9b-FROST) Lelia Aneta Net Research supported in parts by National Science Foundation NSF PHY-1505615


slide-1
SLIDE 1

¡ ¡

¡ ¡ ¡ ¡ ¡ ¡ ¡ ¡ ¡ ¡ ¡ ¡ ¡ ¡ ¡ ¡ ¡ ¡August 22nd, 2017 Polarization observables in double charged pion photo-production with circularly polarized photons off transversely polarized protons (g9b-FROST)

Lelia Aneta Net

Research supported in parts by National Science Foundation NSF PHY-1505615

NSTAR 2017, Columbia, SC

slide-2
SLIDE 2

Outline

  • The Theory and the Models
  • Double pion channel - Missing Resonances Problem
  • FROST Experiment (g9b)
  • Analysis: Extraction of polarization observables
  • Results for
  • Summary

2 ¡

I

J

, Px, Py, P

J x , P J y

slide-3
SLIDE 3

THE THEORY AND THE MODELS ¡

  • Different models

predict different number of nucleon excited states

  • A QCD solution is not known at low energies

(of the order of the nucleon mass and its excited states)

(CQM) ¡

3 ¡

  • Experimental data will help confirm the

existence of these predicted resonances

slide-4
SLIDE 4
  • Biggest contribution to the

photo-production cross section at higher energies

  • Branching ratio for N*

decay via double pion channel could be greater than 70% (e.g. N(1720))

Hagiwara et al., 2002

DOUBLE PION PHOTOPRODUCTION

4 ¡

slide-5
SLIDE 5

POLARIZATION OBSERVABLES

  • Different helicity combinations of the initial nucleon,

final nucleon and the photon give rise to 8 complex transition amplitudes describing the reaction:

  • The cross section sums up the squares of these

transition amplitudes; polarization observables allows access to the amplitude’s phase; reveal more information about the reaction dynamics

  • This work focused on the extraction of 5 polarization
  • bservables: I

J

, Px, Py, P

J x , P J y

5 ¡

slide-6
SLIDE 6

6 ¡

[Yuqing Mao, USC] ¡

PC

Z ¡

[Strauch, 2005]

Previous/Current Studies for Double Pion Photo-production with CLAS

slide-7
SLIDE 7

FROST Experiment (g9 run) at Thomas Jefferson National Accelerator Facility (Newport News, VA)

7 ¡

h0p://www.phys.vt.edu/research/experiments/JLab-­‑Aerial.jpg ¡

slide-8
SLIDE 8
  • Electron beam: - longitudinally polarized:
  • beam energy: 3081.73 MeV
  • Photon beam: - circularly polarized

Eγ ≈ [0.5 − 3.0 GeV]

¯ Pe = 87%

δJ = ¯ Pe (4Eγ/Ee) − (Eγ/Ee)2 4 − (4Eγ/Ee) + (3Eγ/Ee)2

8 ¡

  • FROzen Spin Target (FROST) - transversely

polarized protons (C4H9OH)

  • Target polarization: 76% - 86%
  • Carbon target: unpolarized
  • Polyethylene target: unpolarized

BEAMS AND TARGETS

slide-9
SLIDE 9

CLAS DETECTOR

8 < φ < 140 −25 < θ < 25

9 ¡

  • time and

momentum measurements

  • coverage:

TARGET& TORUS&MAGNET& TIME&OF& FLIGHT& PADDLES& DRIFT& CHAMBERS& BEAM&LINE&

h0ps://www.jlab.org/Hall-­‑B/int-­‑web/clas_large1.jpg ¡

slide-10
SLIDE 10

PHOTON SELECTION PARTICLE ID

t [ns] Δ

  • 10
  • 8
  • 6
  • 4
  • 2

2 4 6 8 10

Counts

1000 2000 3000 4000 5000 6000

3

10 ×

Raw Data Final Selection

  • π

β Δ

  • 0.1 -0.08 -0.06 -0.04 -0.02

0.02 0.04 0.06 0.08 0.1 Counts 1000 2000 3000 4000 5000 6000 7000 8000 9000

3

10 ×

= 0.033 σ Mean+3 = -0.029 σ Mean-3 Sigma = 0.010 Mean = 0.002

+

π

β Δ

  • 0.1 -0.08 -0.06 -0.04 -0.02

0.02 0.04 0.06 0.08 0.1 Counts 1000 2000 3000 4000 5000 6000 7000 8000 9000

3

10 ×

= 0.038 σ Mean+3 = -0.036 σ Mean-3 Sigma = 0.01 Mean = 0.001

p

β Δ

  • 0.1 -0.08 -0.06 -0.04 -0.02

0.02 0.04 0.06 0.08 0.1 Counts 2 4 6 8 10 12 14 16 18 20 22

6

10 ×

= 0.032 σ Mean+3 = -0.029 σ Mean-3 Sigma = 0.010 Mean = 0.002

∆β = βmeas − βcalc = βmeas − p p p2 + m2c2

∆t = tCLAS,vertex − tγ,vertex =

= tST − dST c · βcalc − h tT AGR + Z c i

10 ¡

slide-11
SLIDE 11

γp → pπ+π−

Final State Composition: 2 positive charges and 1 negative charge

¡

~ ~ p → p⇡+⇡−(X) ~ ~ p → ⇡+⇡−(X) ~ ~ p → p⇡−(X) ~ ~ p → p⇡+(X)

Topology 1: Topology 2: Topology 3: Topology 4: ¡

p missing nothing missing π- missing π+ missing

REACTION SELECTION ¡

11 ¡

slide-12
SLIDE 12

12 ¡

]

2

[GeV

X 2

M

  • 0.1
  • 0.05

0.05 0.1 0.15 0.2 0.25 0.3 Events 20 40 60 80 100 120 140 160 180 200 0.72 ± Scale factor= 9.79 0.02 ± Q value = 0.65

Carbon pre-fit Butanol fit Carbon scaled Carbon unscaled

Events ¡

M2

X[ GeV2]

Seed event M2

Q = Signal Signal + Background

i ¡

SIGNAL BACKGROUND SEPARATION: PROBABILISTIC WEIGHTING METHOD

Q value = the probability for a given event i to be a signal (Q=1) or a background event (Q=0)

slide-13
SLIDE 13

13 ¡

Reaction plane

Figure ¡adapted ¡from ¡[Strauch, ¡2005] ¡

Polarization observables for circularly polarized photons off transversely polarized protons

* ¡

slide-14
SLIDE 14

All the final expressions correct for the acceptance effects and for the fact that the target polarization is slightly different for different run groups.

¡ 14 ¡

Simplified observable extraction (for illustration)

¯ Px = 1 ¯ Λ P

i cos αi

P

i Qi cos2 αi

¯ Py = 1 ¯ Λ P

i sin αi

P

i Qi sin2 αi

¯ P

J x

= 1 ¯ Λ 1 ¯ δJ P

i Hi cos αi

P

i Qi cos2 αi

¯ P

J y

= 1 ¯ Λ 1 ¯ δJ P

i Hi sin αi

P

i Qi sin2 αi

slide-15
SLIDE 15

15 ¡

Polarization Observables: Results

Observables fit functions:

PRELIMINARY ¡

I

J

g1c, ¡g9b ¡ comparison ¡

slide-16
SLIDE 16

y

P

* [degrees] φ 90 180 270 360 y

P

  • 0.5
  • 0.4
  • 0.3
  • 0.2
  • 0.1

0.1 0.2 0.3 0.4 0.5 W = 1450 - 1550 MeV

Data Even function fit

* [degrees] φ 90 180 270 360 y

P

  • 0.5
  • 0.4
  • 0.3
  • 0.2
  • 0.1

0.1 0.2 0.3 0.4 0.5 W = 1550 - 1650 MeV

Data Even function fit

* [degrees] φ 90 180 270 360 y

P

  • 0.5
  • 0.4
  • 0.3
  • 0.2
  • 0.1

0.1 0.2 0.3 0.4 0.5 W = 1650 - 1750 MeV

Data Even function fit

* [degrees] φ 90 180 270 360 y

P

  • 0.5
  • 0.4
  • 0.3
  • 0.2
  • 0.1

0.1 0.2 0.3 0.4 0.5 W = 1750 - 1850 MeV

Data Even function fit

* [degrees] φ 90 180 270 360 y

P

  • 0.5
  • 0.4
  • 0.3
  • 0.2
  • 0.1

0.1 0.2 0.3 0.4 0.5 W = 1850 - 1950 MeV

Data Even function fit

* [degrees] φ 90 180 270 360 y

P

  • 0.5
  • 0.4
  • 0.3
  • 0.2
  • 0.1

0.1 0.2 0.3 0.4 0.5 W = 1950 - 2050 MeV

Data Even function fit

* [degrees] φ 90 180 270 360 y

P

  • 0.5
  • 0.4
  • 0.3
  • 0.2
  • 0.1

0.1 0.2 0.3 0.4 0.5 W = 2050 - 2150 MeV

Data Even function fit

* [degrees] φ 90 180 270 360 y

P

  • 0.5
  • 0.4
  • 0.3
  • 0.2
  • 0.1

0.1 0.2 0.3 0.4 0.5 W = 2150 - 2250 MeV

Data Even function fit

* [degrees] φ 90 180 270 360 y

P

  • 0.5
  • 0.4
  • 0.3
  • 0.2
  • 0.1

0.1 0.2 0.3 0.4 0.5 W = 2250 - 2350 MeV

Data Even function fit

* [degrees] φ 90 180 270 360 y

P

  • 0.5
  • 0.4
  • 0.3
  • 0.2
  • 0.1

0.1 0.2 0.3 0.4 0.5 W = 2350 - 2450 MeV

Data Even function fit

* [degrees] φ 90 180 270 360 y

P

  • 0.5
  • 0.4
  • 0.3
  • 0.2
  • 0.1

0.1 0.2 0.3 0.4 0.5 W = 2450 - 2550 MeV

Data Even function fit

x

P

* [degrees] φ 90 180 270 360 x

P

  • 0.3
  • 0.2
  • 0.1

0.1 0.2 0.3 W = 1450 - 1550 MeV

Data Odd function fit

* [degrees] φ 90 180 270 360 x

P

  • 0.3
  • 0.2
  • 0.1

0.1 0.2 0.3 W = 1550 - 1650 MeV

Data Odd function fit

* [degrees] φ 90 180 270 360 x

P

  • 0.3
  • 0.2
  • 0.1

0.1 0.2 0.3 W = 1650 - 1750 MeV

Data Odd function fit

* [degrees] φ 90 180 270 360 x

P

  • 0.3
  • 0.2
  • 0.1

0.1 0.2 0.3 W = 1750 - 1850 MeV

Data Odd function fit

* [degrees] φ 90 180 270 360 x

P

  • 0.3
  • 0.2
  • 0.1

0.1 0.2 0.3 W = 1850 - 1950 MeV

Data Odd function fit

* [degrees] φ 90 180 270 360 x

P

  • 0.3
  • 0.2
  • 0.1

0.1 0.2 0.3 W = 1950 - 2050 MeV

Data Odd function fit

* [degrees] φ 90 180 270 360 x

P

  • 0.3
  • 0.2
  • 0.1

0.1 0.2 0.3 W = 2050 - 2150 MeV

Data Odd function fit

* [degrees] φ 90 180 270 360 x

P

  • 0.3
  • 0.2
  • 0.1

0.1 0.2 0.3 W = 2150 - 2250 MeV

Data Odd function fit

* [degrees] φ 90 180 270 360 x

P

  • 0.3
  • 0.2
  • 0.1

0.1 0.2 0.3 W = 2250 - 2350 MeV

Data Odd function fit

* [degrees] φ 90 180 270 360 x

P

  • 0.3
  • 0.2
  • 0.1

0.1 0.2 0.3 W = 2350 - 2450 MeV

Data Odd function fit

* [degrees] φ 90 180 270 360 x

P

  • 0.3
  • 0.2
  • 0.1

0.1 0.2 0.3 W = 2450 - 2550 MeV

Data Odd function fit

16 ¡ PRELIMINARY ¡ W=1450-2550 MeV

slide-17
SLIDE 17

x

P

* [degrees] φ 90 180 270 360 x

P

  • 1
  • 0.8
  • 0.6
  • 0.4
  • 0.2

0.2 0.4 0.6 0.8 1 W = 1450 - 1550 MeV

Data Even function fit

* [degrees] φ 90 180 270 360 x

P

  • 1
  • 0.8
  • 0.6
  • 0.4
  • 0.2

0.2 0.4 0.6 0.8 1 W = 1550 - 1650 MeV

Data Even function fit

* [degrees] φ 90 180 270 360 x

P

  • 1
  • 0.8
  • 0.6
  • 0.4
  • 0.2

0.2 0.4 0.6 0.8 1 W = 1650 - 1750 MeV

Data Even function fit

* [degrees] φ 90 180 270 360 x

P

  • 1
  • 0.8
  • 0.6
  • 0.4
  • 0.2

0.2 0.4 0.6 0.8 1 W = 1750 - 1850 MeV

Data Even function fit

* [degrees] φ 90 180 270 360 x

P

  • 1
  • 0.8
  • 0.6
  • 0.4
  • 0.2

0.2 0.4 0.6 0.8 1 W = 1850 - 1950 MeV

Data Even function fit

* [degrees] φ 90 180 270 360 x

P

  • 1
  • 0.8
  • 0.6
  • 0.4
  • 0.2

0.2 0.4 0.6 0.8 1 W = 1950 - 2050 MeV

Data Even function fit

* [degrees] φ 90 180 270 360 x

P

  • 1
  • 0.8
  • 0.6
  • 0.4
  • 0.2

0.2 0.4 0.6 0.8 1 W = 2050 - 2150 MeV

Data Even function fit

* [degrees] φ 90 180 270 360 x

P

  • 1
  • 0.8
  • 0.6
  • 0.4
  • 0.2

0.2 0.4 0.6 0.8 1 W = 2150 - 2250 MeV

Data Even function fit

* [degrees] φ 90 180 270 360 x

P

  • 1
  • 0.8
  • 0.6
  • 0.4
  • 0.2

0.2 0.4 0.6 0.8 1 W = 2250 - 2350 MeV

Data Even function fit

* [degrees] φ 90 180 270 360 x

P

  • 1
  • 0.8
  • 0.6
  • 0.4
  • 0.2

0.2 0.4 0.6 0.8 1 W = 2350 - 2450 MeV

Data Even function fit

* [degrees] φ 90 180 270 360 x

P

  • 1
  • 0.8
  • 0.6
  • 0.4
  • 0.2

0.2 0.4 0.6 0.8 1 W = 2450 - 2550 MeV

Data Even function fit

y

P

* [degrees] φ 90 180 270 360 y

P

  • 1
  • 0.8
  • 0.6
  • 0.4
  • 0.2

0.2 0.4 0.6 0.8 1 W = 1450 - 1550 MeV

Data Odd function fit

* [degrees] φ 90 180 270 360 y

P

  • 1
  • 0.8
  • 0.6
  • 0.4
  • 0.2

0.2 0.4 0.6 0.8 1 W = 1550 - 1650 MeV

Data Odd function fit

* [degrees] φ 90 180 270 360 y

P

  • 1
  • 0.8
  • 0.6
  • 0.4
  • 0.2

0.2 0.4 0.6 0.8 1 W = 1650 - 1750 MeV

Data Odd function fit

* [degrees] φ 90 180 270 360 y

P

  • 1
  • 0.8
  • 0.6
  • 0.4
  • 0.2

0.2 0.4 0.6 0.8 1 W = 1750 - 1850 MeV

Data Odd function fit

* [degrees] φ 90 180 270 360 y

P

  • 1
  • 0.8
  • 0.6
  • 0.4
  • 0.2

0.2 0.4 0.6 0.8 1 W = 1850 - 1950 MeV

Data Odd function fit

* [degrees] φ 90 180 270 360 y

P

  • 1
  • 0.8
  • 0.6
  • 0.4
  • 0.2

0.2 0.4 0.6 0.8 1 W = 1950 - 2050 MeV

Data Odd function fit

* [degrees] φ 90 180 270 360 y

P

  • 1
  • 0.8
  • 0.6
  • 0.4
  • 0.2

0.2 0.4 0.6 0.8 1 W = 2050 - 2150 MeV

Data Odd function fit

* [degrees] φ 90 180 270 360 y

P

  • 1
  • 0.8
  • 0.6
  • 0.4
  • 0.2

0.2 0.4 0.6 0.8 1 W = 2150 - 2250 MeV

Data Odd function fit

* [degrees] φ 90 180 270 360 y

P

  • 1
  • 0.8
  • 0.6
  • 0.4
  • 0.2

0.2 0.4 0.6 0.8 1 W = 2250 - 2350 MeV

Data Odd function fit

* [degrees] φ 90 180 270 360 y

P

  • 1
  • 0.8
  • 0.6
  • 0.4
  • 0.2

0.2 0.4 0.6 0.8 1 W = 2350 - 2450 MeV

Data Odd function fit

* [degrees] φ 90 180 270 360 y

P

  • 1
  • 0.8
  • 0.6
  • 0.4
  • 0.2

0.2 0.4 0.6 0.8 1 W = 2450 - 2550 MeV

Data Odd function fit

17 ¡ PRELIMINARY ¡ W=1450-2550 MeV

slide-18
SLIDE 18

y

P

* [degrees] φ 90 180 270 360 y

P

  • 0.5
  • 0.4
  • 0.3
  • 0.2
  • 0.1

0.1 0.2 0.3 0.4 0.5 * = [-1.00 , -0.75] Θ cos W = 1550 - 1650 MeV

Data Even function fit

* [degrees] φ 90 180 270 360 y

P

  • 0.5
  • 0.4
  • 0.3
  • 0.2
  • 0.1

0.1 0.2 0.3 0.4 0.5 * = [-0.75 , -0.50] Θ cos W = 1550 - 1650 MeV

Data Even function fit

* [degrees] φ 90 180 270 360 y

P

  • 0.5
  • 0.4
  • 0.3
  • 0.2
  • 0.1

0.1 0.2 0.3 0.4 0.5 * = [-0.50 , -0.25] Θ cos W = 1550 - 1650 MeV

Data Even function fit

* [degrees] φ 90 180 270 360 y

P

  • 0.5
  • 0.4
  • 0.3
  • 0.2
  • 0.1

0.1 0.2 0.3 0.4 0.5 * = [-0.25 , 0.00] Θ cos W = 1550 - 1650 MeV

Data Even function fit

* [degrees] φ 90 180 270 360 y

P

  • 0.5
  • 0.4
  • 0.3
  • 0.2
  • 0.1

0.1 0.2 0.3 0.4 0.5 * = [0.00 , 0.25] Θ cos W = 1550 - 1650 MeV

Data Even function fit

* [degrees] φ 90 180 270 360 y

P

  • 0.5
  • 0.4
  • 0.3
  • 0.2
  • 0.1

0.1 0.2 0.3 0.4 0.5 * = [0.25 , 0.50] Θ cos W = 1550 - 1650 MeV

Data Even function fit

* [degrees] φ 90 180 270 360 y

P

  • 0.5
  • 0.4
  • 0.3
  • 0.2
  • 0.1

0.1 0.2 0.3 0.4 0.5 * = [0.50 , 0.75] Θ cos W = 1550 - 1650 MeV

Data Even function fit

* [degrees] φ 90 180 270 360 y

P

  • 0.5
  • 0.4
  • 0.3
  • 0.2
  • 0.1

0.1 0.2 0.3 0.4 0.5 * = [0.75 , 1.00] Θ cos W = 1550 - 1650 MeV

Data Even function fit

x

P

* [degrees] φ 90 180 270 360 x

P

  • 0.3
  • 0.2
  • 0.1

0.1 0.2 0.3 * = [-1.00 , -0.75] Θ cos W = 1450 - 1550 MeV

Data Odd function fit

* [degrees] φ 90 180 270 360 x

P

  • 0.3
  • 0.2
  • 0.1

0.1 0.2 0.3 * = [-0.75 , -0.50] Θ cos W = 1450 - 1550 MeV

Data Odd function fit

* [degrees] φ 90 180 270 360 x

P

  • 0.3
  • 0.2
  • 0.1

0.1 0.2 0.3 * = [-0.50 , -0.25] Θ cos W = 1450 - 1550 MeV

Data Odd function fit

* [degrees] φ 90 180 270 360 x

P

  • 0.3
  • 0.2
  • 0.1

0.1 0.2 0.3 * = [-0.25 , 0.00] Θ cos W = 1450 - 1550 MeV

Data Odd function fit

* [degrees] φ 90 180 270 360 x

P

  • 0.3
  • 0.2
  • 0.1

0.1 0.2 0.3 * = [0.00 , 0.25] Θ cos W = 1450 - 1550 MeV

Data Odd function fit

* [degrees] φ 90 180 270 360 x

P

  • 0.3
  • 0.2
  • 0.1

0.1 0.2 0.3 * = [0.25 , 0.50] Θ cos W = 1450 - 1550 MeV

Data Odd function fit

* [degrees] φ 90 180 270 360 x

P

  • 0.3
  • 0.2
  • 0.1

0.1 0.2 0.3 * = [0.50 , 0.75] Θ cos W = 1450 - 1550 MeV

Data Odd function fit

* [degrees] φ 90 180 270 360 x

P

  • 0.3
  • 0.2
  • 0.1

0.1 0.2 0.3 * = [0.75 , 1.00] Θ cos W = 1450 - 1550 MeV

Data Odd function fit

18 ¡ PRELIMINARY ¡ W=1450-­‑1550 ¡MeV ¡, ¡cosΘ*=[-­‑1,1] ¡ W=1550-­‑1650 ¡MeV ¡, ¡cosΘ*=[-­‑1,1] ¡

slide-19
SLIDE 19

y

P

* [degrees] φ 90 180 270 360 y

P

  • 1
  • 0.8
  • 0.6
  • 0.4
  • 0.2

0.2 0.4 0.6 0.8 1 * = [-1.00 , -0.75] Θ cos W = 1550 - 1650 MeV

Data Model calculation Odd function fit

* [degrees] φ 90 180 270 360 y

P

  • 1
  • 0.8
  • 0.6
  • 0.4
  • 0.2

0.2 0.4 0.6 0.8 1 * = [-0.75 , -0.50] Θ cos W = 1550 - 1650 MeV

Data Model calculation Odd function fit

* [degrees] φ 90 180 270 360 y

P

  • 1
  • 0.8
  • 0.6
  • 0.4
  • 0.2

0.2 0.4 0.6 0.8 1 * = [-0.50 , -0.25] Θ cos W = 1550 - 1650 MeV

Data Model calculation Odd function fit

* [degrees] φ 90 180 270 360 y

P

  • 1
  • 0.8
  • 0.6
  • 0.4
  • 0.2

0.2 0.4 0.6 0.8 1 * = [-0.25 , 0.00] Θ cos W = 1550 - 1650 MeV

Data Model calculation Odd function fit

* [degrees] φ 90 180 270 360 y

P

  • 1
  • 0.8
  • 0.6
  • 0.4
  • 0.2

0.2 0.4 0.6 0.8 1 * = [0.00 , 0.25] Θ cos W = 1550 - 1650 MeV

Data Model calculation Odd function fit

* [degrees] φ 90 180 270 360 y

P

  • 1
  • 0.8
  • 0.6
  • 0.4
  • 0.2

0.2 0.4 0.6 0.8 1 * = [0.25 , 0.50] Θ cos W = 1550 - 1650 MeV

Data Model calculation Odd function fit

* [degrees] φ 90 180 270 360 y

P

  • 1
  • 0.8
  • 0.6
  • 0.4
  • 0.2

0.2 0.4 0.6 0.8 1 * = [0.50 , 0.75] Θ cos W = 1550 - 1650 MeV

Data Model calculation Odd function fit

* [degrees] φ 90 180 270 360 y

P

  • 1
  • 0.8
  • 0.6
  • 0.4
  • 0.2

0.2 0.4 0.6 0.8 1 * = [0.75 , 1.00] Θ cos W = 1550 - 1650 MeV

Data Model calculation Odd function fit
  • The comparison between

d a t a a n d t h e m o d e l prediction shows rather a lack of agreement

  • The data will help further

constrain the model for a better agreement

MODEL CALCULATION - DATA COMPARISON Effective Lagrangean Model (A. Fix)

19 ¡

slide-20
SLIDE 20

Summary

  • Overview
  • f the methods used to analyze

double pion photo-production with circularly polarized photon beam off transversely polarized protons and to extract the polarization observables

  • 5 polarization observables were extracted for

W=1450-2550 MeV

  • Comparison with the model shows some similarities with

general features of the data; the data will help constrain the model for a better agreement

  • Data will enter PWA study to help identify missing nucleon

resonances

20 ¡

slide-21
SLIDE 21
slide-22
SLIDE 22

EXTRA SLIDES

slide-23
SLIDE 23
slide-24
SLIDE 24

MvrtZ [cm]

  • 10
  • 5

5 10 15 20 Counts 1000 2000 3000 4000 5000 6000 7000

MVRTZ MVRTZ

Butanol( Events( Carbon( Events(

Photon selection

Butanol events: -3 cm < mvrtZ < +3cm Carbon events: +6cm < mvrtZ <+11cm

βcalc = p p p2 + m2

∆β = βmeas − βcalc

|∆t| < 1 ns

∆t = tCLAS − tT AGR

Analysis: Event Pre-selection

Momentum ¡[GeV/c} ¡ βmeas ¡ Δt ¡[ns] ¡ Events ¡

mvrtZ[cm] ¡

Events ¡

slide-25
SLIDE 25
slide-26
SLIDE 26

Electron beam: - longitudinally polarized:

  • beam energy: 3081.73 MeV

Photon beam: - circularly polarized

TAGGING ¡SYSTEM ¡[B. ¡A. ¡Mecking ¡et ¡al, ¡2003} ¡

Eγ ≈ [20% − 95%Ee] Eγ ≈ [0.5 − 3.0 GeV]

E-counter resolution:

0.001E0

¯ Pe = 87%

δJ = ¯ Pe (4Eγ/Ee) − (Eγ/Ee)2 4 − (4Eγ/Ee) + (3Eγ/Ee)2

σδJ ≈ 3.0%

9 ¡

slide-27
SLIDE 27

TARGETS

  • Repolarized for each run group
  • Polarization checked via NMR

measurements

  • Polarization uncertainty <3.5%
  • FROzen Spin Target (FROST) - transversely polarized protons

(C4H9OH)

  • Carbon target: unpolarized, L=0.15 cm, 6 cm downstream
  • Polyethylene target: unpolarized, L=0.35 cm, 16 cm

downstream

¡ 10 ¡

h0ps://www.jlab.org/highlights/images/physics/CutawayAnnotated-­‑LG.jpg ¡

slide-28
SLIDE 28

Hao ¡Jiang ¡

slide-29
SLIDE 29

7 ¡

Reaction plane

Figure ¡adapted ¡from ¡[Strauch, ¡2005] ¡

Polarization observables for circularly polarized photons off transversely polarized protons

* ¡

slide-30
SLIDE 30

Y 0, Y 180, Y 0

sin α, Y 180 sin α, Y 0 cos α, Y 180 cos α, Y 0 sin 2α, Y 180 sin 2α, Y 0 cos 2α, Y 180 cos 2α

The moments for the two target polarization directions( 0°,180°) are: After adding and subtracting different combinations of these yields we get:

Px = 2 [(Y 0¯ Λ180 + Y 180¯ Λ0) − (Y 0

cos 2α¯

Λ180 + Y 180

cos 2α¯

Λ0)](Y 0

cos α + Y 180 cos α)−

(Y 0¯ Λ180 + Y 180¯ Λ0)2 − (Y 0

cos 2αΛ180 + Y 180 cos 2αΛ0)2 − (Y 0 sin 2α¯

Λ180 + Y 180

sin 2α¯

Λ0)2

−(Y 0

sin 2α¯

Λ180 + Y 180

sin 2α¯

Λ0)(Y 0

sin α + Y 180 sin α)

(Y 0¯ Λ180 + Y 180¯ Λ0)2 − (Y 0

cos 2αΛ180 + Y 180 cos 2αΛ0)2 − (Y 0 sin 2α¯

Λ180 + Y 180

sin 2α¯

Λ0)2

Py = 2 [(Y 0¯ Λ180 + Y 180¯ Λ0) + (Y 0

cos 2α¯

Λ180 + Y 180

cos 2α¯

Λ0)](Y 0

sin α + Y 180 sin α)−

(Y 0¯ Λ180 + Y 180¯ Λ0)2 − (Y 0

cos 2αΛ180 + Y 180 cos 2αΛ0)2 − (Y 0 sin 2α¯

Λ180 + Y 180

sin 2α¯

Λ0)2

−(Y 0

sin 2α¯

Λ180 + Y 180

sin 2α¯

Λ0)(Y 0

cos α + Y 180 cos α)

(Y 0¯ Λ180 + Y 180¯ Λ0)2 − (Y 0

cos 2αΛ180 + Y 180 cos 2αΛ0)2 − (Y 0 sin 2α¯

Λ180 + Y 180

sin 2α¯

Λ0)2

slide-31
SLIDE 31

P

J y

= 2[(Y 0¯ Λ180 + Y 180¯ Λ0) − (Y 0

cos 2α¯

Λ180 + Y 180

cos 2α¯

Λ0)](Y +0

sin α − Y −0 sin α + Y +180 sin α − Y −180 sin α )−

δJ[(Y 0¯ Λ180 + Y 180¯ Λ0)2 − (¯ Λ180Y 0

sin 2α + ¯

Λ0Y 0

sin 2α)2 − (Y 0 cos 2α¯

Λ180 + Y 180

cos 2α¯

Λ0)2]

−(¯ Λ180Y 0

sin 2α + ¯

Λ0Y 180

sin 2α)(Y +0 cos α − Y −0 cos α + Y +180 cos α − Y −180 cos α )

δJ[(Y 0¯ Λ180 + Y 180¯ Λ0)2 − (¯ Λ180Y 0

sin 2α + ¯

Λ0Y 180

sin 2α)2 − (Y 0 cos 2α¯

Λ180 + Y 180

cos 2α¯

Λ0)2]

P

J x

= 2 (¯ Λ180Y 0

sin 2α + ¯

Λ0Y 180

sin 2α)(Y +0 sin α − Y −0 sin α + Y +180 sin α − Y −180 sin α )−

δJ[(¯ Λ180Y 0

sin 2α + ¯

Λ0Y 0

sin 2α)2 − (Y 0¯

Λ180 + Y 180¯ Λ0)2 + (Y 0

cos 2α¯

Λ180 + Y 180

cos 2α¯

Λ0)2]

−[(Y 0¯ Λ180 + Y 180¯ Λ0) − (Y 0

cos 2α¯

Λ180 + Y 180

cos 2α¯

Λ0)](Y +0

cos α − Y −0 cos α + Y +180 cos α − Y −180 cos α )

δJ[(¯ Λ180Y 0

sin 2α + ¯

Λ0Y 180

sin 2α)2 − (Y 0¯

Λ180 + Y 180¯ Λ0)2 + (Y 0

cos 2α¯

Λ180 + Y 180

cos 2α¯

Λ0)2]

slide-32
SLIDE 32

Target ¡polarizakon: ¡(NMR_sign ¡Holding_magnet_sign) ¡e.g. ¡(+ ¡+) ¡and ¡(-­‑ ¡-­‑) ¡means ¡pos.sign; ¡(+ ¡-­‑) ¡ and ¡(-­‑ ¡+) ¡means ¡neg.sign ¡

slide-33
SLIDE 33

POLARIZATION OBSERVABLES

I0 = |M−

1 |2 + |M+ 1 |2 + |M− 2 |2 + |M+ 2 |2 + |M− 3 |2 + |M+ 3 |2 + |M− 4 |2 + |M+ 4 |2

I0Px = 2<(M−

1 M−∗ 3

+ M+

1 M+∗ 3

+ M−

2 M−∗ 4

+ M+

2 M+∗ 4 )

I0Py = 2=(M−

1 M−∗ 3

+ M+

1 M+∗ 3

+ M−

2 M−∗ 4

+ M+

2 M+∗ 4 )

I0I

J

= −|M−

1 |2 + |M+ 1 |2 − |M− 2 |2 + |M+ 2 |2 − |M− 3 |2 + |M+ 3 |2 − |M− 4 |2 + |M+ 4 |2

I0P

J x

= 2<(M−

1 M−∗ 3

+ M+

1 M+∗ 3

M−

2 M−∗ 4

+ M+

2 M+∗ 4 )

I0P

J y

= 2=(M−

1 M−∗ 3

M+

1 M+∗ 3

+ M−

2 M−∗ 4

M+

2 M+∗ 4 )

slide-34
SLIDE 34
slide-35
SLIDE 35

Observables odd/even behavior fit check

slide-36
SLIDE 36
slide-37
SLIDE 37

Target polarization orientation angle

slide-38
SLIDE 38
slide-39
SLIDE 39
slide-40
SLIDE 40
slide-41
SLIDE 41

I

* [degrees] φ 90 180 270 360

I

  • 1
  • 0.8
  • 0.6
  • 0.4
  • 0.2

0.2 0.4 0.6 0.8 1 W = 1450 - 1550 MeV

Data Odd function fit

* [degrees] φ 90 180 270 360

I

  • 1
  • 0.8
  • 0.6
  • 0.4
  • 0.2

0.2 0.4 0.6 0.8 1 W = 1550 - 1650 MeV

Data Odd function fit

* [degrees] φ 90 180 270 360

I

  • 1
  • 0.8
  • 0.6
  • 0.4
  • 0.2

0.2 0.4 0.6 0.8 1 W = 1650 - 1750 MeV

Data Odd function fit

* [degrees] φ 90 180 270 360

I

  • 1
  • 0.8
  • 0.6
  • 0.4
  • 0.2

0.2 0.4 0.6 0.8 1 W = 1750 - 1850 MeV

Data Odd function fit

* [degrees] φ 90 180 270 360

I

  • 1
  • 0.8
  • 0.6
  • 0.4
  • 0.2

0.2 0.4 0.6 0.8 1 W = 1850 - 1950 MeV

Data Odd function fit

* [degrees] φ 90 180 270 360

I

  • 1
  • 0.8
  • 0.6
  • 0.4
  • 0.2

0.2 0.4 0.6 0.8 1 W = 1950 - 2050 MeV

Data Odd function fit

* [degrees] φ 90 180 270 360

I

  • 1
  • 0.8
  • 0.6
  • 0.4
  • 0.2

0.2 0.4 0.6 0.8 1 W = 2050 - 2150 MeV

Data Odd function fit

* [degrees] φ 90 180 270 360

I

  • 1
  • 0.8
  • 0.6
  • 0.4
  • 0.2

0.2 0.4 0.6 0.8 1 W = 2150 - 2250 MeV

Data Odd function fit

* [degrees] φ 90 180 270 360

I

  • 1
  • 0.8
  • 0.6
  • 0.4
  • 0.2

0.2 0.4 0.6 0.8 1 W = 2250 - 2350 MeV

Data Odd function fit

* [degrees] φ 90 180 270 360

I

  • 1
  • 0.8
  • 0.6
  • 0.4
  • 0.2

0.2 0.4 0.6 0.8 1 W = 2350 - 2450 MeV

Data Odd function fit

* [degrees] φ 90 180 270 360

I

  • 1
  • 0.8
  • 0.6
  • 0.4
  • 0.2

0.2 0.4 0.6 0.8 1 W = 2450 - 2550 MeV

Data Odd function fit
slide-42
SLIDE 42

MODEL CALCULATION AND DATA COMPARISON Effective Lagrangean Model (A. Fix)

  • Nucleon and Delta Born terms, Resonances Δ(1232), N*(1440),

N*(1520) , N*(1535), Δ(1620), N*(1675), N*(1680), N*(1700), N*(1720)

[A.Fix, ¡H. ¡Arenhövel, ¡Eur.Phy. ¡J.A ¡25, ¡115 ¡(2005)] ¡

23 ¡

  • The model takes as an input the four momentum vectors of the

incident and the final state particles and calculates the differential cross-section in the center of mass frame

slide-43
SLIDE 43

SYSTEMATIC UNCERTAINTIES

17 ¡