neutron form factorsrelnp.jinr.ru/ishepp-xx/presentations/wojtsekhowski.pdf · neutron form factors...
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Neutron Form Factors Bogdan Wojtsekhowski, Jefferson Lab
Neutron structure and EM form factors Recent experiment 3He(e,e’n) at Jlab Flavor decomposition of nucleon FFs The transverse neutron densities Future GEN&GMN and GMN/GMP at high Q2
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October 4, 2010 Bogdan Wojtsekhowski Baldin 2010 slide 2
Highlights of the neutron Prediction: Rutherford 1920 Discovery: Chadwick 1932 Magnetic moment:Esterman&Stern 1934, Alvarez&Bloch 1940 Determination of spin 1/2: Schwinger 1937 Direct observation of the structure: Hofstadter 1950th SLAC measurement of Gn
M up to 10 GeV2 Time like FFs: DM2, FENICE Polarizabilities: SAL, Mainz, Lund Polarized electron beam era: Sinclair’s electron source in 1977 CEBAF with polarimeter and polarized targets in 1990th Unification of DIS/FFs/DVCS in GPDs by Muller, Ji, Radyushkin Gn
M/GpM precision measurement by Brooks etal in 2001
Polarized He-3: laser pumping Gn
E/GnM measurements at NIKHEF, Mainz, JLab, BATES
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October 4, 2010 Bogdan Wojtsekhowski Baldin 2010 slide 3
Electro-Magnetic Form Factors
Rosenbluth (1950) !
Akhiezer (1958)!Arnold, Carlson !and Gross (1981)!
Guichon &!Vanderhaeghen!
Afanasev et al.!Blunden et al.!
One-photon approximation, αem = 1/137, hadron current !
Full expression for M has three complex functions, F1, F2, F3 !
old GE,M are real !functions of t=-Q2!
Extra terms contribute less than few % to σR !
At large Q2 study of GE require use of !polarization observables - FFs at CEBAF!
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October 4, 2010 Bogdan Wojtsekhowski Baldin 2010 slide 4
Photon - Neutron Interaction
At Q2 of several GeV2 massive photon vibrates in q-qbar, which can’t propagate far - already inside of the nucleon => still such q-qbar propagates as a VM !
Q2=0
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October 4, 2010 Bogdan Wojtsekhowski Baldin 2010 slide 5
GPDs of nucleon Muller (94), Ji (97), Radyushkin (97) :!
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October 4, 2010 Bogdan Wojtsekhowski Baldin 2010 slide 6
GPDs information a lot to measure P.Kroll, Excl.-07
Ji’s sum rule for quark orbital momentum
!Lqv" = 1
2
! 10 dx [xEq
v(x, ! = 0, t = 0) + xqv(x) # !qv(x)]
DVCS will access low t, large Q2 kinematics
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October 4, 2010 Bogdan Wojtsekhowski Baldin 2010 slide 7
3-d picture of the nucleon
Proton form factors, transverse charge & current densities
Structure functions, quark longitudinal momentum & helicity distributions
Correlated quark momentum and helicity distributions in transverse space - GPDs
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Sachs Form Factors of the nucleon
]2 [GeV2Q
0 5 10 15
DG
pµ/
p MG
0.7
0.8
0.9
1.0
1.1
1.2
Borkowski
Sill
Bosted
Walker
Andivahis
Diehl
Kelly
BBBA05
]2 [GeV2Q
0 5 10 15
DG
nµ/
n MG
0.4
0.6
0.8
1.0
1.2 Rock
Lung
Markowitz
Anklin(1994)
Bruins
Anklin(1998)
Kubon
Lachniet
GPD
Kelly
BBBA05
]2 [GeV2Q
0 5 10 15
p M/G
p EG
pµ
0.0
0.5
1.0
GEp(1)
GEp(2)
GEp(3)
Diehl
Kelly
BBBA05
]2 [GeV2Q
n M/G
n EG
nµ
0.0
0.2
0.4
0.6
0.8
1.0
RCQM
GPD
VMD
Kelly
BBBA05
DSE
1 2 3 4 5 6 7 8 9 10 11 12 13 14 15
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October 4, 2010 Bogdan Wojtsekhowski Baldin 2010 slide 9
Recent experiment at Jlab
:!
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October 4, 2010 Bogdan Wojtsekhowski Baldin 2010 slide 10
Jlab high Q2 GEN experiment Since 1984, when Blankleider&Woloshin suggested ,!several experiments of this type have been performed at NIKHEF-K !and Mainz (A1, A3) for Q2 up to 0.7 GeV2 , a big success in part due to!a new accurate 3-body calculation possible at low Q2 (Glockle et al.)!
At Q2 above 1-2 GeV2 Glauber method becomes sufficiently " " " " " " " accurate (Sarksian)!
Electron-polarized neutron luminosity and high polarization of 3He!target made measurement about 10 times more effective than with ND3. In combination with a large acceptance electron spectrometer the total enhancement is more than 100, which allows to reach 3.5 GeV2 !
• Polarized target !• Electron spectrometer!• Neutron detector!
Require super!
:!
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October 4, 2010 Bogdan Wojtsekhowski Baldin 2010 slide 11
Double polarization method
Selection of QE !by cut P < 150 MeV !
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Hall A GEn experiment
Beam
Target Neutron arm
Electron arm
October 4, 2010 slide 12 Bogdan Wojtsekhowski Baldin 2010
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Target Neutron arm
Electron arm Neutron arm
Pumping chamber
Laser light
Polarized beam
Target chamber
Scattered electron
Recoiled neutron
Rb + K
Polarization pumping
Jpolarized nuclei.x P2nuclei
GEn
Beam Hall A GE
n experiment
October 4, 2010 slide 13 Bogdan Wojtsekhowski Baldin 2010
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• Solid angle of 76 msr (12 times higher than HRS) • 40 cm long target • Momentum resolution of 1%
Beam
Target Electron arm Neutron arm
Hall A GEn experiment
October 4, 2010 slide 14 Bogdan Wojtsekhowski Baldin 2010
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October 4, 2010 Bogdan Wojtsekhowski Baldin 2010 slide 15
Electron Spectrometer Useful ΔQ2/Q2 ~ 0.1 with max Ω leads to a large aspect ratio, limited just of 30o for the polar. target. BigBite was designed at NIKHEF for aspect ratio Δθ/Δφ = 1/5. Spectrometer has solid angle up to 95 msr.!
With luminosity of JLab polarized target, 1037 cm-2/s, the open geometry - a dipole spectrometer - works well when!all MWDCs located behind the magnet.!
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October 4, 2010 Bogdan Wojtsekhowski Baldin 2010 slide 16
Neutron Detector • Match BigBite solid angle " for QE kinematics !• Flight distance ~ 10 m !• Operation at 3.1037 cm2/s!
• 1.6 x 5 m2 active area !• 6-7 layers (~ 250 bars)!• 2 veto layers (~ 200)!• 0.38 ns time resolution!
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October 4, 2010 Bogdan Wojtsekhowski Baldin 2010 slide 17
Target monitoring
Single arm rate (neutral pions)
smaller is better for reduction of the systematic errors
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October 4, 2010 Bogdan Wojtsekhowski Baldin 2010 slide 18
Data analysis: step 1 - Time-of-Flight
Raw events (BLACK lines) have significant accidental level and large tail for slower protons
RED lines present events after cut on e’-n angular correlation: accidentals and tails almost gone
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October 4, 2010 Bogdan Wojtsekhowski Baldin 2010 slide 19
Analysis: step 2 - qperp vs W; 1.7 GeV2 perpendicular “q” = q x tan(θqh); W2 = M2 + 2M(E-E’) - Q2
Quasi elastic events dominates after Full Cuts applied max value of used perp. q
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October 4, 2010 Bogdan Wojtsekhowski Baldin 2010 slide 20
Analysis: step 3 - W distribution
for 3.5 GeV2 quasi-elastic signal very small in e,e’ after angular correlation cut peak is just as suppose to be
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The results GEn experiment
Target Neutron arm
Electron arm
October 4, 2010 slide 21 Bogdan Wojtsekhowski Baldin 2010
]2 [GeV2Q
n M/G
n EG
nµ
0.0
0.2
0.4
0.6
0.8
RCQM
GPD
VMD
DSE
= 150 MeV!pQCD,
= 300 MeV!pQCD,
0.5 1.0 1.5 2.0 2.5 3.0 3.5 4.0
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The JLab GEn experiments
Target Neutron arm
Electron arm
October 4, 2010 slide 22 Bogdan Wojtsekhowski Baldin 2010
]2 [GeV2Q
0 1 2 3 4
D/G
n EG
0.0
0.2
0.4
0.6
0.8
1.0
]2 [GeV2Q
0 1 2 3 4
D/G
n EG
0.0
0.2
0.4
0.6
0.8
1.0
Electric Form Factor of the Neutron
without JLab GEn experiments
significantly better accuracy for high Q2
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October 4, 2010 Bogdan Wojtsekhowski Baldin 2010 slide 23
Recent experiment at Bates
D(e,e’n) DRIFT CHAMBERS
CERENKOV COUNTERS
SCINTILLATORS NEUTRON COUNTERS
TARGET BEAM
BEAM
COILS
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October 4, 2010 Bogdan Wojtsekhowski Baldin 2010 slide 24
Running experiment at Mainz
]2 [GeV2Qn M
/Gn E
Gn!
0.0
0.2
0.4
0.6
0.8
RCQM - Miller (2006)
GPD - DiehlVMD - Lomon (2005)
DSE - RobertsOur Kelly fit
= 150 MeV!, 1
/F2F
= 300 MeV!, 1
/F2F
Passchier, NIKHEF
Herberg, MAMI
Ostrick, MAMI
Meyerhoff, MAMI
Golak, MAMI
Bermuth, MAMI
Plaster, JLab
Zhu, JLab
Warren, JLab
Glazier, MAMI
Geis, BATES
E02-013
A1 Result - Prelim.
0.5 1.0 1.5 2.0 2.5 3.0 3.5 4.0
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Flavor view with EMFFs
October 4, 2010 slide 25 Bogdan Wojtsekhowski Baldin 2010
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]2 [GeV2Q
0 5 10 15
p M/G
p EG
pµ
0.0
0.5
1.0
GEp(1)
GEp(2)
GEp(3)
Diehl
Kelly
BBBA05
]2 [GeV2Q
n M/G
n EG
nµ
0.0
0.2
0.4
0.6
0.8
1.0
RCQM
GPD
VMD
Kelly
BBBA05
DSE
1 2 3 4 5 6 7 8 9 10 11 12 13 14 15
The goal is understanding of the nucleon
F1,dual = Fu,p
1 = 2 F1p + F1n F1,lone = Fd,p
1 = 2 F1n + F1p
Fp = +23 Fdual + !1
3 Flone
Fn = !13 Fdual + +2
3 Flone
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F1d
(2)/F1u
(2) with proton and neutron FFs
Fu
1 = 2 F1p + F1n
Fd
1 = 2 F1n + F1p
F1 = GE +!GM
1 + !
F2 = !GE !GM
1 + !
Lattice calculation => very good agreement with the trend, need accuracy DSE (ANL) => good, possibly a signature of dominant degrees of freedom Our data will require a new fit of Ed and Eu GPDs
u 1/F
d 1F
0.2
0.4
0.6
RCQM
GPD
Lattice
]2 [GeV2Q0.5 1.0 1.5 2.0 2.5 3.0 3.5 4.0
u 2F
u-1!/
d 2F
d-1!
0.5
1.0
1.5
VMD
DSE
October 4, 2010 slide 27 Bogdan Wojtsekhowski Baldin 2010
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Form Factors ratios
]2 [GeV2Q
0.5 1.0 1.5 2.0 2.5 3.0 3.5 4.0
u 1/F
d 1F
0.2
0.4
0.6
RCQM - Miller
Lattice
Diehl et al.
Galster fitq(qq) Faddeev&DSE
x
0.2 0.3 0.4 0.5 0.6 0.7 0.8 0.9 1.0
d/u
0.0
0.2
0.4
0.6
JLab Projected Data
He DIS3
H/ 3
]2 [GeV2Q
0.0 0.5 1.0 1.5 2.0 2.5 3.0 3.5 4.0
u 1/F
u 2F
u-1!
0.0
0.1
0.2
0.3
0.4
0.5
F1,
lone/
F1,
dual
!!
1
du
alF
2,d
ual/
F1,d
ual
]2 [GeV2Q
0.0 0.5 1.0 1.5 2.0 2.5 3.0 3.5 4.0
d 1/F
d 2F
d-1!
0.5
1.0
1.5
RCQM - Miller (2005)
GPD - Diehl
Galster + Kelly
VMD - Lomon (2006)
Kelly Param.
!!
1
loneF
2,lo
ne/
F1,
lone
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Form Factors ratios
]2 [GeV2Q
0.5 1.0 1.5 2.0 2.5 3.0 3.5 4.0
u 1/F
d 1F
0.2
0.4
0.6
RCQM - Miller
Lattice
Diehl et al.
Galster fitq(qq) Faddeev&DSE
x
0.2 0.3 0.4 0.5 0.6 0.7 0.8 0.9 1.0
d/u
0.0
0.2
0.4
0.6
JLab Projected Data
He DIS3
H/ 3
]2 [GeV2Q
0.0 0.5 1.0 1.5 2.0 2.5 3.0 3.5 4.0
u 1/F
u 2F
u-1!
0.0
0.1
0.2
0.3
0.4
0.5
F1,
lone/
F1,
dual
!!
1
du
alF
2,d
ual/
F1,d
ual
correspondence e.g. via GPDs
]2 [GeV2Q
0.0 0.5 1.0 1.5 2.0 2.5 3.0 3.5 4.0
d 1/F
d 2F
d-1!
0.5
1.0
1.5
RCQM - Miller (2005)
GPD - Diehl
Galster + Kelly
VMD - Lomon (2006)
Kelly Param.
!!
1
loneF
2,lo
ne/
F1,
lone
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Form Factors ratios
]2 [GeV2Q
0.5 1.0 1.5 2.0 2.5 3.0 3.5 4.0
u 1/F
d 1F
0.2
0.4
0.6
RCQM - Miller
Lattice
Diehl et al.
Galster fitq(qq) Faddeev&DSE
x
0.2 0.3 0.4 0.5 0.6 0.7 0.8 0.9 1.0
d/u
0.0
0.2
0.4
0.6
JLab Projected Data
He DIS3
H/ 3
]2 [GeV2Q
0.0 0.5 1.0 1.5 2.0 2.5 3.0 3.5 4.0
u 1/F
u 2F
u-1!
0.0
0.1
0.2
0.3
0.4
0.5
F1,
lone/
F1,
dual
!!
1
du
alF
2,d
ual/
F1,d
ual
Dual and Lone quark distribution FFs
correspondence e.g. via GPDs
]2 [GeV2Q
0.0 0.5 1.0 1.5 2.0 2.5 3.0 3.5 4.0
d 1/F
d 2F
d-1!
0.5
1.0
1.5
RCQM - Miller (2005)
GPD - Diehl
Galster + Kelly
VMD - Lomon (2006)
Kelly Param.
!!
1
loneF
2,lo
ne/
F1,
lone
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- What is a unique signature of the diquark configuration?
]2 [GeV2Q
0.0 0.5 1.0 1.5 2.0 2.5 3.0 3.5 4.0
u 1/F
u 2F
u-1!
0.0
0.1
0.2
0.3
0.4
0.5
The goal is understanding of the nucleon
Results of E02-013 Hall A GEn
!!
1
du
alF
2,d
ual/
F1,d
ual
Fp = +23 Fdual + !1
3 Flone
Fn = !13 Fdual + +2
3 Flone
]2 [GeV2Q
0.0 0.5 1.0 1.5 2.0 2.5 3.0 3.5 4.0
d 1/F
d 2F
d-1!
0.5
1.0
1.5
RCQM - Miller (2005)
GPD - Diehl
Galster + Kelly
VMD - Lomon (2006)
Kelly Param.
!!
1
loneF
2,lo
ne/
F1,
lone
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- A diquark configuration? - An effect of orbital motion?
]2 [GeV2Q
0.0 0.5 1.0 1.5 2.0 2.5 3.0 3.5 4.0
u 1/F
u 2F
u-1!
0.0
0.1
0.2
0.3
0.4
0.5
Results of E02-013 Hall A GEn
The goal is understanding of the nucleon
0.3 !!
1
du
alF
2,d
ual/
F1,d
ual
F1,dual = Fu,p
1 = 2 F1p + F1n F1,lone = Fd,p
1 = 2 F1n + F1p
]2 [GeV2Q
0.0 0.5 1.0 1.5 2.0 2.5 3.0 3.5 4.0
d 1/F
d 2F
d-1!
0.5
1.0
1.5
RCQM - Miller (2005)
GPD - Diehl
Galster + Kelly
VMD - Lomon (2006)
Kelly Param.
!!
1
loneF
2,lo
ne/
F1,
lone
1.2
Interesting observation: F2/F1 = R is constant in the Q2-range 1 - 3.5 GeV2
![Page 33: Neutron Form Factorsrelnp.jinr.ru/ishepp-xx/presentations/Wojtsekhowski.pdf · Neutron Form Factors Bogdan Wojtsekhowski, Jefferson Lab Neutron structure and EM form factors Recent](https://reader030.vdocument.in/reader030/viewer/2022041013/5ec1590a113e1d655752a9d8/html5/thumbnails/33.jpg)
October 4, 2010 Bogdan Wojtsekhowski Baldin 2010 slide 33
EMFFs and GPDs
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October 4, 2010 Bogdan Wojtsekhowski Baldin 2010 slide 34
GMn/GMp and GPDs
)2 (GeV2Q0 2 4 6 8 10 12 14 16 18 20
p 1/F
n 1-F
0
0.1
0.2
0.3
0.4
0.5
0.6
0.7
0.8
0.9
1Kelly FitBBBA FitAlberico FitCLAS dataSLAC dataHall A projected
)2 (GeV2Q0 2 4 6 8 10 12 14 16 18 20
u 1/F
d 1F
-0.4
-0.3
-0.2
-0.1
0
0.1
0.2
0.3
0.4
0.5
0.6Kelly FitBBBA FitAlberico FitCLAS dataSLAC dataHall A projected
GPD model (Guidal etal):
F1d < 0 presents an interesting
challenge to such a model F1,
lone/
F1,
dual
![Page 35: Neutron Form Factorsrelnp.jinr.ru/ishepp-xx/presentations/Wojtsekhowski.pdf · Neutron Form Factors Bogdan Wojtsekhowski, Jefferson Lab Neutron structure and EM form factors Recent](https://reader030.vdocument.in/reader030/viewer/2022041013/5ec1590a113e1d655752a9d8/html5/thumbnails/35.jpg)
The transverse neutron densities
October 4, 2010 slide 35 Bogdan Wojtsekhowski Baldin 2010
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October 4, 2010 Bogdan Wojtsekhowski Baldin 2010 slide 36
Impact parameter GPDs
Muller, Ji, Radyushkin!
M.Burkardt!
P.Kroll: u/d segregation!
G.Miller!
![Page 37: Neutron Form Factorsrelnp.jinr.ru/ishepp-xx/presentations/Wojtsekhowski.pdf · Neutron Form Factors Bogdan Wojtsekhowski, Jefferson Lab Neutron structure and EM form factors Recent](https://reader030.vdocument.in/reader030/viewer/2022041013/5ec1590a113e1d655752a9d8/html5/thumbnails/37.jpg)
October 4, 2010 Bogdan Wojtsekhowski Baldin 2010 slide 37
Transverse densities
C.Carlson & M.Vaderhaeghen !
transversely polarized neutron has huge EDM
![Page 38: Neutron Form Factorsrelnp.jinr.ru/ishepp-xx/presentations/Wojtsekhowski.pdf · Neutron Form Factors Bogdan Wojtsekhowski, Jefferson Lab Neutron structure and EM form factors Recent](https://reader030.vdocument.in/reader030/viewer/2022041013/5ec1590a113e1d655752a9d8/html5/thumbnails/38.jpg)
Flavor decomposition of IMF densities
[fm]y
b-1 -0.8 -0.6 -0.4 -0.2 0 0.2 0.4 0.6 0.8 1
]-2
[fm
T!
-0.5
0
0.5
1
1.5
2
2.5
3
3.5
4
u quark
d quark
Polarized Transverse Charge Density
b [fm]0 0.1 0.2 0.3 0.4 0.5 0.6 0.7 0.8 0.9 1
]-2
[fm
D!
0
0.5
1
1.5
2
2.5
3
3.5
4
u quark
d quark
Dirac Transverse Charge Density
[fm]y
b0 0.1 0.2 0.3 0.4 0.5 0.6 0.7 0.8 0.9 1
]-2
[fm
P!
-0.6
-0.4
-0.2
0
0.2
0.4
0.6 u quark
d quark
Pauli Transverse Charge Density
r [fm]
0.0 0.5 1.0 1.5 2.0 2.5 3.0
]-1
(r)
[fm
! 2
r"
4
-0.10
-0.05
0.00
0.05
0.10
0.15
0.20Charge Distribution in the Neutron
Ordinary charge density
![Page 39: Neutron Form Factorsrelnp.jinr.ru/ishepp-xx/presentations/Wojtsekhowski.pdf · Neutron Form Factors Bogdan Wojtsekhowski, Jefferson Lab Neutron structure and EM form factors Recent](https://reader030.vdocument.in/reader030/viewer/2022041013/5ec1590a113e1d655752a9d8/html5/thumbnails/39.jpg)
October 4, 2010 Bogdan Wojtsekhowski Baldin 2010 slide 39
Density in polarized neutron
C.Carlson & M.Vaderhaeghen !
Spin
Momentum transfer
u
d
Transversity effects in
bx
by
![Page 40: Neutron Form Factorsrelnp.jinr.ru/ishepp-xx/presentations/Wojtsekhowski.pdf · Neutron Form Factors Bogdan Wojtsekhowski, Jefferson Lab Neutron structure and EM form factors Recent](https://reader030.vdocument.in/reader030/viewer/2022041013/5ec1590a113e1d655752a9d8/html5/thumbnails/40.jpg)
October 4, 2010 slide 40
Rotation of u/d quarks in neutron
neutron GEn Bogdan Wojtsekhowski, JLab
Let see how quark rotation leads to u/d separation:
virtual photon quark
motion inside nucleon
M.Burkardt (2003)
amplitude is small
amplitude is large
Bogdan Wojtsekhowski Baldin 2010
![Page 41: Neutron Form Factorsrelnp.jinr.ru/ishepp-xx/presentations/Wojtsekhowski.pdf · Neutron Form Factors Bogdan Wojtsekhowski, Jefferson Lab Neutron structure and EM form factors Recent](https://reader030.vdocument.in/reader030/viewer/2022041013/5ec1590a113e1d655752a9d8/html5/thumbnails/41.jpg)
October 4, 2010 slide 41
Rotation of u/d quarks in neutron
neutron GEn Bogdan Wojtsekhowski, JLab
Interaction selects one side because of rotation
M.Burkardt (2003)
Let see how quark rotation leads to u/d separation:
virtual photon quark
amplitude is small
amplitude is large
Bogdan Wojtsekhowski Baldin 2010
![Page 42: Neutron Form Factorsrelnp.jinr.ru/ishepp-xx/presentations/Wojtsekhowski.pdf · Neutron Form Factors Bogdan Wojtsekhowski, Jefferson Lab Neutron structure and EM form factors Recent](https://reader030.vdocument.in/reader030/viewer/2022041013/5ec1590a113e1d655752a9d8/html5/thumbnails/42.jpg)
October 4, 2010 slide 42 neutron GEn Bogdan Wojtsekhowski, JLab
Rotation of u/d quarks in neutron u-quark d-quark
Bogdan Wojtsekhowski Baldin 2010
![Page 43: Neutron Form Factorsrelnp.jinr.ru/ishepp-xx/presentations/Wojtsekhowski.pdf · Neutron Form Factors Bogdan Wojtsekhowski, Jefferson Lab Neutron structure and EM form factors Recent](https://reader030.vdocument.in/reader030/viewer/2022041013/5ec1590a113e1d655752a9d8/html5/thumbnails/43.jpg)
The u/d “separation”, observed in Form Factor data, is likely a result of the collective rotation of the u-quark and the d-quark, which is going in opposite directions
u-quark d-quark
interaction selects
Rotation of u/d quarks in neutron
October 4, 2010 slide 43 Bogdan Wojtsekhowski Baldin 2010
![Page 44: Neutron Form Factorsrelnp.jinr.ru/ishepp-xx/presentations/Wojtsekhowski.pdf · Neutron Form Factors Bogdan Wojtsekhowski, Jefferson Lab Neutron structure and EM form factors Recent](https://reader030.vdocument.in/reader030/viewer/2022041013/5ec1590a113e1d655752a9d8/html5/thumbnails/44.jpg)
Future neutron FFs experiments
October 4, 2010 slide 44 Bogdan Wojtsekhowski Baldin 2010
![Page 45: Neutron Form Factorsrelnp.jinr.ru/ishepp-xx/presentations/Wojtsekhowski.pdf · Neutron Form Factors Bogdan Wojtsekhowski, Jefferson Lab Neutron structure and EM form factors Recent](https://reader030.vdocument.in/reader030/viewer/2022041013/5ec1590a113e1d655752a9d8/html5/thumbnails/45.jpg)
Future neutron FFs experiments
October 4, 2010 slide 45 Bogdan Wojtsekhowski Baldin 2010
D(e,e’n)p / D(e,e’p)n – under preparation
Double pol. He-3(e,e’n)pp – under preparation
D(e,e’n)p – requires a new AY data from JINR ( talk by J. Annand)
![Page 46: Neutron Form Factorsrelnp.jinr.ru/ishepp-xx/presentations/Wojtsekhowski.pdf · Neutron Form Factors Bogdan Wojtsekhowski, Jefferson Lab Neutron structure and EM form factors Recent](https://reader030.vdocument.in/reader030/viewer/2022041013/5ec1590a113e1d655752a9d8/html5/thumbnails/46.jpg)
Optimization of the experimental setup Hadron Arm
Beam
Target
Electron Arm
.
.
17 m
Neutron Magnetic Form Factor
GEM
BigBenBNL
BigBiteGasCher
ECalo
HCalo
48D48
Electron Arm
Beam
.
.
Target
Proton form factors ratio, GEp(5): E12!07!109
Proton Arm
Lead!glassCalorimeter
BNLINFN
HCalo
Al filter
48D48
GEM
GEM
GEM
BigBenGEM
Beam
Target
Hadron Arm
Electron Arm
.
.
17 m
HCalo
48D48
BigBenBNL
BigBiteGasCher
ECalo
Neutron form factors, E12!09!016 and E12!09!019
GEM
Proton Magnetic Form Factor
Neutron form factors ratio, GEn(2):E12-09-016
October 4, 2010 Bogdan Wojtsekhowski Baldin 2010 slide 46
Neutron/proton form factors ratio: E12-09-019 Proton magnetic form factor: E12-07-108
![Page 47: Neutron Form Factorsrelnp.jinr.ru/ishepp-xx/presentations/Wojtsekhowski.pdf · Neutron Form Factors Bogdan Wojtsekhowski, Jefferson Lab Neutron structure and EM form factors Recent](https://reader030.vdocument.in/reader030/viewer/2022041013/5ec1590a113e1d655752a9d8/html5/thumbnails/47.jpg)
October 4, 2010 Bogdan Wojtsekhowski Baldin 2010 slide 47
Neutron/proton form factors ratio: E12-09-019
D(e,e’n)p / D(e,e’p)n
Beam
Target
Hadron Arm
Electron Arm
.
.
17 m
HCalo
48D48
BigBenBNL
BigBiteGasCher
ECalo
Neutron form factors, E12!09!016 and E12!09!019
GEM
Deuterium
![Page 48: Neutron Form Factorsrelnp.jinr.ru/ishepp-xx/presentations/Wojtsekhowski.pdf · Neutron Form Factors Bogdan Wojtsekhowski, Jefferson Lab Neutron structure and EM form factors Recent](https://reader030.vdocument.in/reader030/viewer/2022041013/5ec1590a113e1d655752a9d8/html5/thumbnails/48.jpg)
Beam
Target
Hadron Arm
Electron Arm
.
.
17 m
HCalo
48D48
BigBenBNL
BigBiteGasCher
ECalo
Neutron form factors, E12!09!016 and E12!09!019
GEM
Neutron form factors ratio, GEn(2):E12-09-016
October 4, 2010 Bogdan Wojtsekhowski Baldin 2010 slide 48
Double polarized He-3(e,e’n)pp
Polarized He-3
Polarized
![Page 49: Neutron Form Factorsrelnp.jinr.ru/ishepp-xx/presentations/Wojtsekhowski.pdf · Neutron Form Factors Bogdan Wojtsekhowski, Jefferson Lab Neutron structure and EM form factors Recent](https://reader030.vdocument.in/reader030/viewer/2022041013/5ec1590a113e1d655752a9d8/html5/thumbnails/49.jpg)
CLAS 12 BigBite + SBS
October 4, 2010 Bogdan Wojtsekhowski Baldin 2010 slide 49
)2 (GeV2Q0 2 4 6 8 10 12 14 16 18 20
DG
nµ/
n MG
0.2
0.4
0.6
0.8
1
1.2
BBBA FitKelly FitAlberico FitCLAS dataSLAC data
Hall A E12-09-19
value on BBBA fit
Hall B E12-07-104
value shifted to 1.1
Gilman, Quinn, and BW
12 GeV GMn experiment
W.Brook etal
![Page 50: Neutron Form Factorsrelnp.jinr.ru/ishepp-xx/presentations/Wojtsekhowski.pdf · Neutron Form Factors Bogdan Wojtsekhowski, Jefferson Lab Neutron structure and EM form factors Recent](https://reader030.vdocument.in/reader030/viewer/2022041013/5ec1590a113e1d655752a9d8/html5/thumbnails/50.jpg)
October 4, 2010 Bogdan Wojtsekhowski Baldin 2010 slide 50
Cates, Riordan, and BW
]2 [GeV2Q
n M/G
n EG
n!
0.0
0.5
1.0RCQM - Miller
GPD - Diehl
VMD - Lomon (2005)
Faddeev&DSE - Roberts = 300 MeV!,
1/F2F
Passchier, NIKHEFHerberg, MAMI
Ostrick, MAMI
Meyerhoff, MAMI
Golak, MAMI
Bermuth, MAMI
Plaster, JLab
Zhu, JLab
Warren, JLab
Glazier, MAMI
Geis, BATES
E02-013
E12-09-016, Hall A
2 4 6 8 10 12 14 16 18 20
12 GeV GEn experiment
![Page 51: Neutron Form Factorsrelnp.jinr.ru/ishepp-xx/presentations/Wojtsekhowski.pdf · Neutron Form Factors Bogdan Wojtsekhowski, Jefferson Lab Neutron structure and EM form factors Recent](https://reader030.vdocument.in/reader030/viewer/2022041013/5ec1590a113e1d655752a9d8/html5/thumbnails/51.jpg)
October 4, 2010 Bogdan Wojtsekhowski Baldin 2010 slide 51
CEBAF electron beam in 2013(4)
Hall A will be the first hall which will get the beam
• Beam energy 11/12 GeV
• Beam power 1 MW
• Beam current (Hall A/D) 85/5 µA
• Beam polarization 85%
• Emittance @ 12 GeV 10 nm-rad
• Energy spread @ 12 GeV 0.02%
• Beam spot ~ 0.1mm
• Simultaneous beam delivery Up to 3 halls
![Page 52: Neutron Form Factorsrelnp.jinr.ru/ishepp-xx/presentations/Wojtsekhowski.pdf · Neutron Form Factors Bogdan Wojtsekhowski, Jefferson Lab Neutron structure and EM form factors Recent](https://reader030.vdocument.in/reader030/viewer/2022041013/5ec1590a113e1d655752a9d8/html5/thumbnails/52.jpg)
October 4, 2010 Bogdan Wojtsekhowski Baldin 2010 slide 52
THANKS
![Page 53: Neutron Form Factorsrelnp.jinr.ru/ishepp-xx/presentations/Wojtsekhowski.pdf · Neutron Form Factors Bogdan Wojtsekhowski, Jefferson Lab Neutron structure and EM form factors Recent](https://reader030.vdocument.in/reader030/viewer/2022041013/5ec1590a113e1d655752a9d8/html5/thumbnails/53.jpg)
October 4, 2010 Bogdan Wojtsekhowski Baldin 2010 slide 53
Polarized target 3He = p + p + n! S + S’ + P waves! Pn = 0.86 PHe !
Rb + K mixture has shortened spin-up time to 5-8 hours. The hybrid method of optical pumping was used here for the first time in the nuclear target.!
Pumping chamber!
Laser light!
Polarized beam!
Target chamber!
Scattered electron!
Recoiled neutron!
PHe of 50% with 8 µA beam !