Post on 18-Jul-2020
How do the Quarks and Gluons spin in theProton ?
— The View from HERMES —
E.C. Aschenauer
DESY
E.C. Aschenauer Pan Pacific, Tokyo, July 2005 1
The Spin Structure of the Nucleon
Naive Parton Model:∆uv + ∆dv = 1
=⇒ ∆uv =4
3,∆dv =
−1
3
BUT
1988 EMC measured:Σ = 0.123 ± 0.013 ± 0.019
=⇒ Spin Puzzle
1
2=
1
2(∆uv + ∆dv)
F2 from HERA tells:
Gluons are important !
=⇒ sea quarks ∆qs
=⇒ ∆G
1
2=
1
2(∆uv + ∆dv + ∆qs
︸︷︷︸) + ∆G
∆us,∆ds,∆u,∆d,∆s,∆s
Full description of Jq & Jg
needsorbital angular momentum
1
2=
1
2(∆uv + ∆dv + ∆qs)︸ ︷︷ ︸
+Lq + (∆G + Lg)
∆Σ
E.C. Aschenauer Pan Pacific, Tokyo, July 2005 2
The Spin Structure of the Nucleon
Naive Parton Model:∆uv + ∆dv = 1
=⇒ ∆uv =4
3,∆dv =
−1
3
BUT
1988 EMC measured:Σ = 0.123 ± 0.013 ± 0.019
=⇒ Spin Puzzle
1
2=
1
2(∆uv + ∆dv)
F2 from HERA tells:
Gluons are important !
=⇒ sea quarks ∆qs
=⇒ ∆G
1
2=
1
2(∆uv + ∆dv + ∆qs
︸︷︷︸) + ∆G
∆us,∆ds,∆u,∆d,∆s,∆s
Full description of Jq & Jg
needsorbital angular momentum
1
2=
1
2(∆uv + ∆dv + ∆qs)︸ ︷︷ ︸
+Lq + (∆G + Lg)
∆Σ
E.C. Aschenauer Pan Pacific, Tokyo, July 2005 2
The Spin Structure of the Nucleon
Naive Parton Model:∆uv + ∆dv = 1
=⇒ ∆uv =4
3,∆dv =
−1
3
BUT
1988 EMC measured:Σ = 0.123 ± 0.013 ± 0.019
=⇒ Spin Puzzle
1
2=
1
2(∆uv + ∆dv)
F2 from HERA tells:
Gluons are important !
=⇒ sea quarks ∆qs
=⇒ ∆G
1
2=
1
2(∆uv + ∆dv + ∆qs
︸︷︷︸) + ∆G
∆us,∆ds,∆u,∆d,∆s,∆s
Full description of Jq & Jg
needsorbital angular momentum
1
2=
1
2(∆uv + ∆dv + ∆qs)︸ ︷︷ ︸
+Lq + (∆G + Lg)
∆Σ
E.C. Aschenauer Pan Pacific, Tokyo, July 2005 2
HERA at DESY
E.C. Aschenauer Pan Pacific, Tokyo, July 2005 3
HERA at DESY
BeamDirection
Polarimeter
TransversePolarimeter
Spin Rotator
Spin Rotator
pe
Spin RotatorSpin Rotator
Spin Rotator
Spin Rotator
Longitudinal
• HERA-e self-polarizing by emissionof synchrotron radiation−→ Transverse Polarization
• Longitudinal polarization at HERMESvia spin-rotators
• Online measurement of beampolarization with two Comptonback scattering polarimeters
Comparison of rise time curves
0
20
40
60
80
6 6.5 7 7.5 8Time [hours]
Pol
ariz
atio
n [%
]
Transverse Polarimeter
Longitudinal Polarimeter
Beam Polarisation < PB >∼ 55%∆PB/PB = 1.8− 3.4%
E.C. Aschenauer Pan Pacific, Tokyo, July 2005 3
The HERMES Detector
E.C. Aschenauer Pan Pacific, Tokyo, July 2005 4
The HERMES Detector
1
0
2
−1
−2
m
LUMINOSITY
CHAMBERSDRIFT
FC 1/2
TARGETCELL
DVC
MC 1−3
HODOSCOPE H0
MONITOR
BC 1/2
BC 3/4 TRD
PROP.CHAMBERS
FIELD CLAMPS
PRESHOWER (H2)
STEEL PLATE CALORIMETER
DRIFT CHAMBERS
TRIGGER HODOSCOPE H1
0 1 2 3 4 5 6 7 8 9 10
RICH
SILICON
270 mrad
270 mrad
MUON HODOSCOPEWIDE ANGLE
FRONTMUONHODO
MAGNET
m
IRON WALL
MUON HODOSCOPES
e+
27.5 GeV
140 mrad
170 mrad
170 mrad
140 mrad
Kinematic Range: 0.02 ≤ x ≤ 0.8 at Q2 ≥ 1GeV2 and W ≥ 2GeVΘx ≤ 175 mrad, 40 mrad ≤ Θy ≤ 140 mrad
Reconstruction: δp/p 1.0 - 2.0%, δΘ ≤ 1.0mrad
E.C. Aschenauer Pan Pacific, Tokyo, July 2005 4
The HERMES Detector
1
0
2
−1
−2
m
LUMINOSITY
CHAMBERSDRIFT
FC 1/2
TARGETCELL
DVC
MC 1−3
HODOSCOPE H0
MONITOR
BC 1/2
BC 3/4 TRD
PROP.CHAMBERS
FIELD CLAMPS
PRESHOWER (H2)
STEEL PLATE CALORIMETER
DRIFT CHAMBERS
TRIGGER HODOSCOPE H1
0 1 2 3 4 5 6 7 8 9 10
RICH
SILICON
270 mrad
270 mrad
MUON HODOSCOPEWIDE ANGLE
FRONTMUONHODO
MAGNET
m
IRON WALL
MUON HODOSCOPES
e+
27.5 GeV
140 mrad
170 mrad
170 mrad
140 mrad
Kinematic Range: 0.02 ≤ x ≤ 0.8 at Q2 ≥ 1GeV2 and W ≥ 2GeVΘx ≤ 175 mrad, 40 mrad ≤ Θy ≤ 140 mrad
Reconstruction: δp/p 1.0 - 2.0%, δΘ ≤ 1.0mrad
Internal Gas Target:−→He ,
−→D ,
−→H ,H↑ unpol: H2, D2, He, N2, Ne, Ar, Kr, Xe
E.C. Aschenauer Pan Pacific, Tokyo, July 2005 4
The HERMES Detector
1
0
2
−1
−2
m
LUMINOSITY
CHAMBERSDRIFT
FC 1/2
TARGETCELL
DVC
MC 1−3
HODOSCOPE H0
MONITOR
BC 1/2
BC 3/4 TRD
PROP.CHAMBERS
FIELD CLAMPS
PRESHOWER (H2)
STEEL PLATE CALORIMETER
DRIFT CHAMBERS
TRIGGER HODOSCOPE H1
0 1 2 3 4 5 6 7 8 9 10
RICH
SILICON
270 mrad
270 mrad
MUON HODOSCOPEWIDE ANGLE
FRONTMUONHODO
MAGNET
m
IRON WALL
MUON HODOSCOPES
e+
27.5 GeV
140 mrad
170 mrad
170 mrad
140 mrad
Kinematic Range: 0.02 ≤ x ≤ 0.8 at Q2 ≥ 1GeV2 and W ≥ 2GeVΘx ≤ 175 mrad, 40 mrad ≤ Θy ≤ 140 mrad
Reconstruction: δp/p 1.0 - 2.0%, δΘ ≤ 1.0mrad
Internal Gas Target:−→He ,
−→D ,
−→H ,H↑ unpol: H2, D2, He, N2, Ne, Ar, Kr, Xe
Particle ID: TRD, Preshower, Calorimeter⇒ 1997: Cerenkov 1998 ⇒: RICH + Muon-ID
E.C. Aschenauer Pan Pacific, Tokyo, July 2005 4
DIS Kinematics
Inclusive Scattering:
u
*γ
u
(E’, p’)
d
e
q
(E, p)
N
detect scattered lepton
Q2 lab= 4EE′ sin2( θ
2) νlab= E − E′
W 2 lab= M2 + 2Mν − Q2
xlab= Q2
2Mνy
lab= ν
E= p·q
p·k
Q2 determines what can be resolved in theproton
Semi-Inclusive Scattering:
u
*γ
π+
u
(E’, p’)
d
e
q
π
(E, p)
p
KN
detect scattered lepton and
produced hadrons
η =log(Eh
cm−ph||)
2∗(Ehcm+ph
||)
zlab= Eh
ν
E.C. Aschenauer Pan Pacific, Tokyo, July 2005 5
DIS Kinematics
Inclusive Scattering:
u
*γ
u
(E’, p’)
d
e
q
(E, p)
N
detect scattered lepton
Q2 lab= 4EE′ sin2( θ
2) νlab= E − E′
W 2 lab= M2 + 2Mν − Q2
xlab= Q2
2Mνy
lab= ν
E= p·q
p·k
Q2 determines what can be resolved in theproton
Semi-Inclusive Scattering:
u
*γ
π+
u
(E’, p’)
d
e
q
π
(E, p)
p
KN
detect scattered lepton and
produced hadrons
η =log(Eh
cm−ph||)
2∗(Ehcm+ph
||)
zlab= Eh
ν
E.C. Aschenauer Pan Pacific, Tokyo, July 2005 5
Deep Inelastic Scattering
Cross Section: d2σdΩdE2 = α2E′
Q2ELµν(k, q, s)︸ ︷︷ ︸
Wµν(P, q, S)︸ ︷︷ ︸
leptonic hadronic
Lµν : purely electromagnetic =⇒ calculable in QED
Wµν = −gµνF1
(x,Q2
)+pµpν
νF2
(x,Q2
)
+iεµνλσ qλ
ν
(Sσg1
(x,Q2
)+ 1
ν(p · qSσ − S · qpσ)g2
(x,Q2
))
(for spin 1) −b1
(x,Q2
)rµν + 1
6b2
(x,Q2
)(sµν + tµν + uµν)
+12b3
(x,Q2
)(sµν − uµν) + 1
2b4
(x,Q2
)(sµν − tµν)
F1,F2: Unpolarized Structure Functions=⇒ describe momentum distribution of quarks
g1,g2: Polarized Structure Functions=⇒ describe helicity distribution of quarks
E.C. Aschenauer Pan Pacific, Tokyo, July 2005 6
Virtual Photon Asymmetry
σ3/2 ∼ q−(x)
~Sγ + ~SN = 3/2
~SN = − ~Sq
• Virtual photon γ∗ can only couple to quarks of opposite helicity
E.C. Aschenauer Pan Pacific, Tokyo, July 2005 7
Virtual Photon Asymmetry
σ3/2 ∼ q−(x)
~Sγ + ~SN = 3/2
~SN = − ~Sq
σ1/2 ∼ q+(x)
~Sγ + ~SN = 1/2
~SN = ~Sq
• Virtual photon γ∗ can only couple to quarks of opposite helicity
• Select q+(x) or q−(x) by changing the orientation of target nucleonspin or helicity of incident lepton beam
E.C. Aschenauer Pan Pacific, Tokyo, July 2005 7
Virtual Photon Asymmetry
σ3/2 ∼ q−(x)
~Sγ + ~SN = 3/2
~SN = − ~Sq
σ1/2 ∼ q+(x)
~Sγ + ~SN = 1/2
~SN = ~Sq
• Virtual photon γ∗ can only couple to quarks of opposite helicity
• Select q+(x) or q−(x) by changing the orientation of target nucleonspin or helicity of incident lepton beam
• Different targets =⇒ sensitivity to different quark flavors
E.C. Aschenauer Pan Pacific, Tokyo, July 2005 7
Virtual Photon Asymmetry
σ3/2 ∼ q−(x)
~Sγ + ~SN = 3/2
~SN = − ~Sq
σ1/2 ∼ q+(x)
~Sγ + ~SN = 1/2
~SN = ~Sq
• Virtual photon γ∗ can only couple to quarks of opposite helicity
• Select q+(x) or q−(x) by changing the orientation of target nucleonspin or helicity of incident lepton beam
• Different targets =⇒ sensitivity to different quark flavors
Quark Helicity Distributions:
∆qf (x) := q+f (x) − q−f (x)
( f : u,d, s,u,d, s )
E.C. Aschenauer Pan Pacific, Tokyo, July 2005 7
F1(x) = 12
∑
i e2i (q
+i (x) + q−i (x)) = 1
2
∑
i e2qi(x)
momentum distribution of quarks
g1(x) = 12
∑
i e2i (q
+i (x) − q−i (x)) = 1
2
∑
i e2∆qi(x)
helicity distribution of quarks
Virtual Photon Asymmetries:
A1 =σ 1
2−σ 3
2
σ 12+σ 3
2
= g1−γ2g2
F1A2 = σTL
σT= γ(g1+g2)
F1
Measurable Asymmetries:
A‖ = σ→⇐−σ
→⇒
σ→⇐+σ
→⇒
A⊥ = σ↑→−σ↑←
σ↑→+σ↑←
A‖ = D(A1 + ηA2) A⊥ = d(A2 + ξA1)
With: D, d,R, ε, γ, ξ, η being kinematic factorsE.C. Aschenauer Pan Pacific, Tokyo, July 2005 8
World data on g1/F1
Proton > Deuterium
0
0.2
0.4
0.6
0.8
1
10-4
10-3
10-2
10-1
1
E 143
E 155 (Q2-averaged by HERMES)
SMC
HERMES
g1p /
F1p
x
<Q2 >/
GeV
2
10-1
1
10
10-4
10-3
10-2
10-1
1
-0.1
0
0.1
0.2
0.3
0.4
0.5
0.6
10-4
10-3
10-2
10-1
1
HERMES
E 143
E 155 (Q2-averaged by HERMES)
SMC
COMPASS
g1d /
F1d
x
<Q2 >/
GeV
2
10-1
1
10
10-4
10-3
10-2
10-1
1
Data given at measured < Q2 >: 0.02 - 58 GeV2
A|| =1
PbPt
N→⇐L
→⇒
− N→⇒L
→⇐
N→⇐L
→⇒ + N
→⇒L
→⇐
g1
F1
=1
1 + γ2
»
A||
D+ (γ − η)A2
–
E.C. Aschenauer Pan Pacific, Tokyo, July 2005 9
World data on xg1(x,Q2)
0
0.02
0.04
0.06
10-4
10-3
10-2
10-1
0
0.02
0.04
10-4
10-3
10-2
10-1
-0.04
-0.02
0
0.02
10-4
10-3
10-2
10-1
xg1
HERMESSMCE155E143
proton
COMPASS
deuteron
E142E154JLAB
neutron (3He)
x
gp1 > gD
1 > g3He1
very precise proton data
most precise deuteron data
0
0.02
0.04
0.06
10-4
10-3
10-2
10-1
0
0.02
0.04
10-4
10-3
10-2
10-1
-0.04
-0.02
0
0.02
10-4
10-3
10-2
10-1
xg1
HERMESSMCE155E143
proton
COMPASS
deuteron
x
neutron (from g1p and g1
d)
gp1 > gD
1 > gn1
very precise proton data
most precise deuteron data
most precise neutron data
gd1 =
1
2(1− 3
2wD)(gp
1 + gn1)
in measured range (0.021-0.9):∫
gp1 = 0.1246 ± 0.0032 ± 0.0074
∫
gd1 = 0.0452 ± 0.0015 ± 0.0017
E.C. Aschenauer Pan Pacific, Tokyo, July 2005 10
World data on xg1(x,Q2)
0
0.02
0.04
0.06
10-4
10-3
10-2
10-1
0
0.02
0.04
10-4
10-3
10-2
10-1
-0.04
-0.02
0
0.02
10-4
10-3
10-2
10-1
xg1
HERMESSMCE155E143
proton
COMPASS
deuteron
E142E154JLAB
neutron (3He)
x
gp1 > gD
1 > g3He1
very precise proton data
most precise deuteron data
0
0.02
0.04
0.06
10-4
10-3
10-2
10-1
0
0.02
0.04
10-4
10-3
10-2
10-1
-0.04
-0.02
0
0.02
10-4
10-3
10-2
10-1
xg1
HERMESSMCE155E143
proton
COMPASS
deuteron
x
neutron (from g1p and g1
d)
gp1 > gD
1 > gn1
very precise proton data
most precise deuteron data
most precise neutron data
gd1 =
1
2(1− 3
2wD)(gp
1 + gn1)
in measured range (0.021-0.9):∫
gp1 = 0.1246 ± 0.0032 ± 0.0074
∫
gd1 = 0.0452 ± 0.0015 ± 0.0017
E.C. Aschenauer Pan Pacific, Tokyo, July 2005 10
The structure function b1(x,Q2)
Tensor structure function:
b1 =1
2
∑
q
e2q(2q0 − (q+ + q−))
Adzz =
(σ→⇐ + σ
→⇒) − 2σ0
σ→⇐ + σ
→⇒ + σ0
= −3
2
b1
F1
L µν
Wµν
k
e
k’e’
γ∗ q
p
d
Θ
γ∗
z q q+ 0q
E.C. Aschenauer Pan Pacific, Tokyo, July 2005 11
The structure function b1(x,Q2)
• First measurement of Adzz and bd
1
• Adzz 6= 0
• Adzz ∼ 1%
• bd1 > 0 at small x
• in measured range (0.002-0.85):∫
bd1 = (1.05± 0.34± 0.35) · 10−2
• Qualitative agreement withcoherent double-scatteringmodels
-0.02
-0.01
0
0.01
0.02
10-2
10-1
1x
Azzd
-0.05
0
0.05
0.1
0.15
10-2
10-1
1
b1d
10-1
1
10-2
10-1
1x
⟨Q2 ⟩/G
eV2
E.C. Aschenauer Pan Pacific, Tokyo, July 2005 12
The structure function b1(x,Q2)
• First measurement of Adzz and bd
1
• Adzz 6= 0
• Adzz ∼ 1%
• bd1 > 0 at small x
• in measured range (0.002-0.85):∫
bd1 = (1.05± 0.34± 0.35) · 10−2
• Qualitative agreement withcoherent double-scatteringmodels
-0.02
-0.01
0
0.01
0.02
10-2
10-1
1x
Azzd
-0.05
0
0.05
0.1
0.15
10-2
10-1
1
b1d
10-1
1
10-2
10-1
1x
⟨Q2 ⟩/G
eV2
E.C. Aschenauer Pan Pacific, Tokyo, July 2005 12
Semi-inclusive DIS
String Breaking
u_
d_
π0
u_
u_
u_
ρ−
ud0
ud0
π0
π+
π0
−π
u_
u
ud
u
d
u
uu
u
p
incoming leptonscattered lepton
virtual photon
uud
target nucleon
E.C. Aschenauer Pan Pacific, Tokyo, July 2005 13
Semi-inclusive DIS
String Breaking
u_
d_
π0
u_
u_
u_
ρ−
ud0
ud0
π0
π+
π0
−π
u_
u
ud
u
d
u
uu
u
p
incoming leptonscattered lepton
virtual photon
uud
target nucleon
Correlation between detected hadron and struck qf=⇒ ’Flavor - Separation’
Inclusive DIS:∆Σ = (∆u + ∆u + ∆d + ∆d + ∆s + ∆s)Semi-inclusive DIS:∆u,∆u,∆d,∆d,∆s,∆s
In LO-QCD:
Ah1(x,Q2) =
σh1/2 − σh
3/2
σh1/2 + σh
3/2
=1 + R(x,Q2)
1 + γ2·∑
f e2f ∆qf (x,Q2)
∫dzDh
f (z,Q2)∑
f e2f qf (x,Q2)
∫dzDh
f (z,Q2)
(∆qf ),qf (Polarized) quark distributionsDh
f (z) fragmentation functions giving the probability that a (struck) quarkof flavor f fragments into a hadron of type h
E.C. Aschenauer Pan Pacific, Tokyo, July 2005 14
∆q-Extraction• Rewrite Photon-Nucleon Asymmetry
Ah1(x)
g2=0' C ·∑
q
e2qq(x)
∫dzDh
q (z)∑
q′ e2q′q′(x)
∫dzDh
q′(z)︸ ︷︷ ︸
∆q(x)
q(x)
Phq (x, z)
• Purity P hq (x, z): probability hadron h originates from an event with struck
quark f; completely unpolarized quantity
• Extract ∆q by solving:
~A = P ~Q
~A= (A1,p(x),A1,d(x),Aπ±1,p(x),Aπ±
1,d(x),AK±
1,d(x))
~Q= (∆uu
, ∆dd
, ∆uu
, ∆d
d, ∆s
s, ∆s
s)
E.C. Aschenauer Pan Pacific, Tokyo, July 2005 15
Measured Hadron Asymmetries
-0.1
0
0.1
0.2
0.3
0.4
0.5
10 -1
0.03 0.1
x
-0.1
0
0.1
0.2
0.3
0.4
0.5A1
A1,d
-0.1
0
0.1
0.2
0.3
0.4
0.5
10 -1
A1,dAh+
SMC
-0.1
0
0.1
0.2
0.3
0.4
0.5
10 -1
A1,dAπ+
-0.1
0
0.1
0.2
0.3
0.4
0.5
10 -1
A1,dAK+
-0.1
0
0.1
0.2
0.3
0.4
0.5
10 -1
0.03 0.1 0.4
x
-0.1
0
0.1
0.2
0.3
0.4
0.5A1,dAh−
SMC
-0.1
0
0.1
0.2
0.3
0.4
0.5
10 -1
0.03 0.1 0.4
x
A1,dAπ−
-0.1
0
0.1
0.2
0.3
0.4
0.5
10 -1
0.03 0.1 0.4x
A1,dAK−
0
0.2
0.4
0.6
0.8
10 -1
0.03 0.1
x
A1
A1,p
0
0.2
0.4
0.6
0.8
10 -1
A1,pAh+
SMC
0
0.2
0.4
0.6
0.8
10 -1
A1,pAπ+
0
0.2
0.4
0.6
0.8
10 -1
0.03 0.1 0.4
x
A1,pAh−
SMC
0
0.2
0.4
0.6
0.8
10 -1
0.03 0.1 0.4x
A1,pAπ−
Deuterium
Proton
-0.1
0
0.1
0.2
0.3
0.4
0.5
10 -1
0.03 0.1
x
-0.1
0
0.1
0.2
0.3
0.4
0.5A1
A1,d
-0.1
0
0.1
0.2
0.3
0.4
0.5
10 -1
A1,dAh+
SMC
-0.1
0
0.1
0.2
0.3
0.4
0.5
10 -1
A1,dAπ+
-0.1
0
0.1
0.2
0.3
0.4
0.5
10 -1
A1,dAK+
-0.1
0
0.1
0.2
0.3
0.4
0.5
10 -1
0.03 0.1 0.4
x
-0.1
0
0.1
0.2
0.3
0.4
0.5A1,dAh−
SMC
-0.1
0
0.1
0.2
0.3
0.4
0.5
10 -1
0.03 0.1 0.4
x
A1,dAπ−
-0.1
0
0.1
0.2
0.3
0.4
0.5
10 -1
0.03 0.1 0.4x
A1,dAK−
0
0.2
0.4
0.6
0.8
10 -1
0.03 0.1
x
A1
A1,p
0
0.2
0.4
0.6
0.8
10 -1
A1,pAh+
SMC
0
0.2
0.4
0.6
0.8
10 -1
A1,pAπ+
0
0.2
0.4
0.6
0.8
10 -1
0.03 0.1 0.4
x
A1,pAh−
SMC
0
0.2
0.4
0.6
0.8
10 -1
0.03 0.1 0.4x
A1,pAπ−
Deuterium
Proton
• AK−
1 (x) ≈ 0 !! =⇒ K− = (us)is an all–sea object
• statistics sufficient for5-parameter fit
Q = (∆u
u,∆d
d,∆u
u,∆d
d,∆s
s,∆s
s= 0)
E.C. Aschenauer Pan Pacific, Tokyo, July 2005 16
Measured Hadron Asymmetries
-0.1
0
0.1
0.2
0.3
0.4
0.5
10 -1
0.03 0.1
x
-0.1
0
0.1
0.2
0.3
0.4
0.5A1
A1,d
-0.1
0
0.1
0.2
0.3
0.4
0.5
10 -1
A1,dAh+
SMC
-0.1
0
0.1
0.2
0.3
0.4
0.5
10 -1
A1,dAπ+
-0.1
0
0.1
0.2
0.3
0.4
0.5
10 -1
A1,dAK+
-0.1
0
0.1
0.2
0.3
0.4
0.5
10 -1
0.03 0.1 0.4
x
-0.1
0
0.1
0.2
0.3
0.4
0.5A1,dAh−
SMC
-0.1
0
0.1
0.2
0.3
0.4
0.5
10 -1
0.03 0.1 0.4
x
A1,dAπ−
-0.1
0
0.1
0.2
0.3
0.4
0.5
10 -1
0.03 0.1 0.4x
A1,dAK−
0
0.2
0.4
0.6
0.8
10 -1
0.03 0.1
x
A1
A1,p
0
0.2
0.4
0.6
0.8
10 -1
A1,pAh+
SMC
0
0.2
0.4
0.6
0.8
10 -1
A1,pAπ+
0
0.2
0.4
0.6
0.8
10 -1
0.03 0.1 0.4
x
A1,pAh−
SMC
0
0.2
0.4
0.6
0.8
10 -1
0.03 0.1 0.4x
A1,pAπ−
Deuterium
Proton
-0.1
0
0.1
0.2
0.3
0.4
0.5
10 -1
0.03 0.1
x
-0.1
0
0.1
0.2
0.3
0.4
0.5A1
A1,d
-0.1
0
0.1
0.2
0.3
0.4
0.5
10 -1
A1,dAh+
SMC
-0.1
0
0.1
0.2
0.3
0.4
0.5
10 -1
A1,dAπ+
-0.1
0
0.1
0.2
0.3
0.4
0.5
10 -1
A1,dAK+
-0.1
0
0.1
0.2
0.3
0.4
0.5
10 -1
0.03 0.1 0.4
x
-0.1
0
0.1
0.2
0.3
0.4
0.5A1,dAh−
SMC
-0.1
0
0.1
0.2
0.3
0.4
0.5
10 -1
0.03 0.1 0.4
x
A1,dAπ−
-0.1
0
0.1
0.2
0.3
0.4
0.5
10 -1
0.03 0.1 0.4x
A1,dAK−
0
0.2
0.4
0.6
0.8
10 -1
0.03 0.1
x
A1
A1,p
0
0.2
0.4
0.6
0.8
10 -1
A1,pAh+
SMC
0
0.2
0.4
0.6
0.8
10 -1
A1,pAπ+
0
0.2
0.4
0.6
0.8
10 -1
0.03 0.1 0.4
x
A1,pAh−
SMC
0
0.2
0.4
0.6
0.8
10 -1
0.03 0.1 0.4x
A1,pAπ−
Deuterium
Proton
• AK−
1 (x) ≈ 0 !! =⇒ K− = (us)is an all–sea object
• statistics sufficient for5-parameter fit
Q = (∆u
u,∆d
d,∆u
u,∆d
d,∆s
s,∆s
s= 0)
E.C. Aschenauer Pan Pacific, Tokyo, July 2005 16
Quark Polarizations0
0.5
10-1
∆u/u
-0.5
0
10-1
∆d/d
-1
0
1
10-1
∆u–/u–
-1
0
1
10-1
∆d–/d–
-1
0
1
10-1
∆s/s
0
5
10
10-1
⟨Q2⟩/GeV2
0.03 0.1 0.6
x
∆qf (x)
qf (x):=
q+f (x)
qf (x)− q−f (x)
qf (x)
• ∆u(x)/u(x) > 0=⇒ polarized parallel to theproton spin
• ∆d(x)/d(x) < 0=⇒ polarized opposite tothe proton spin
• ∆u
u∼ ∆d
d∼ ∆s
s∼ 0
E.C. Aschenauer Pan Pacific, Tokyo, July 2005 17
Quark Polarizations0
0.5
10-1
∆u/u
-0.5
0
10-1
∆d/d
-1
0
1
10-1
∆u–/u–
-1
0
1
10-1
∆d–/d–
-1
0
1
10-1
∆s/s
0
5
10
10-1
⟨Q2⟩/GeV2
0.03 0.1 0.6
x
∆qf (x)
qf (x):=
q+f (x)
qf (x)− q−f (x)
qf (x)
• ∆u(x)/u(x) > 0=⇒ polarized parallel to theproton spin
• ∆d(x)/d(x) < 0=⇒ polarized opposite tothe proton spin
• ∆u
u∼ ∆d
d∼ ∆s
s∼ 0
E.C. Aschenauer Pan Pacific, Tokyo, July 2005 17
Quark Polarizations0
0.5
10-1
∆u/u
-0.5
0
10-1
∆d/d
-1
0
1
10-1
∆u–/u–
-1
0
1
10-1
∆d–/d–
-1
0
1
10-1
∆s/s
0
5
10
10-1
⟨Q2⟩/GeV2
0.03 0.1 0.6
x
∆qf (x)
qf (x):=
q+f (x)
qf (x)− q−f (x)
qf (x)
• ∆u(x)/u(x) > 0=⇒ polarized parallel to theproton spin
• ∆d(x)/d(x) < 0=⇒ polarized opposite tothe proton spin
• ∆u
u∼ ∆d
d∼ ∆s
s∼ 0
E.C. Aschenauer Pan Pacific, Tokyo, July 2005 17
Quark Polarizations0
0.5
10-1
∆u/u
-0.5
0
10-1
∆d/d
-1
0
1
10-1
∆u–/u–
-1
0
1
10-1
∆d–/d–
-1
0
1
10-1
∆s/s
0
5
10
10-1
⟨Q2⟩/GeV2
0.03 0.1 0.6
x
∆qf (x)
qf (x):=
q+f (x)
qf (x)− q−f (x)
qf (x)
• ∆u(x)/u(x) > 0=⇒ polarized parallel to theproton spin
• ∆d(x)/d(x) < 0=⇒ polarized opposite tothe proton spin
• ∆u
u∼ ∆d
d∼ ∆s
s∼ 0
E.C. Aschenauer Pan Pacific, Tokyo, July 2005 17
Polarized Quark Densities
0
0.2
10-1
x⋅∆u
-0.2
0
10-1
x⋅∆d
-0.1
0
10-1
GRSV 2000LO val
BB 01 LOx⋅∆u
–
Q2=2.5GeV2
-0.1
0
10-1
x⋅∆d–
-0.1
0
10-1
x⋅∆s
0.03 0.1 0.6
x
∆qf (x) := q+f (x) − q−f (x)
• ∆u(x) and ∆d(x)good agreement with NLO-QCD fit
• ∆u(x),∆d(x) ∼ 0
• No indication for ∆s(x) < 0
• in measured range (0.023-0.6):∫
∆u = -0.002 ± 0.043∫
∆d = -0.054 ± 0.035∫
∆s = +0.028 ± 0.034
E.C. Aschenauer Pan Pacific, Tokyo, July 2005 18
Polarized Quark Densities
0
0.2
10-1
x⋅∆u
-0.2
0
10-1
x⋅∆d
-0.1
0
10-1
GRSV 2000LO val
BB 01 LOx⋅∆u
–
Q2=2.5GeV2
-0.1
0
10-1
x⋅∆d–
-0.1
0
10-1
x⋅∆s
0.03 0.1 0.6
x
∆qf (x) := q+f (x) − q−f (x)
• ∆u(x) and ∆d(x)good agreement with NLO-QCD fit
• ∆u(x),∆d(x) ∼ 0
• No indication for ∆s(x) < 0
• in measured range (0.023-0.6):∫
∆u = -0.002 ± 0.043∫
∆d = -0.054 ± 0.035∫
∆s = +0.028 ± 0.034
E.C. Aschenauer Pan Pacific, Tokyo, July 2005 18
Polarized Quark Densities
0
0.2
10-1
x⋅∆u
-0.2
0
10-1
x⋅∆d
-0.1
0
10-1
GRSV 2000LO val
BB 01 LOx⋅∆u
–
Q2=2.5GeV2
-0.1
0
10-1
x⋅∆d–
-0.1
0
10-1
x⋅∆s
0.03 0.1 0.6
x
∆qf (x) := q+f (x) − q−f (x)
• ∆u(x) and ∆d(x)good agreement with NLO-QCD fit
• ∆u(x),∆d(x) ∼ 0
• No indication for ∆s(x) < 0
• in measured range (0.023-0.6):∫
∆u = -0.002 ± 0.043∫
∆d = -0.054 ± 0.035∫
∆s = +0.028 ± 0.034
E.C. Aschenauer Pan Pacific, Tokyo, July 2005 18
SU(2)-Flavor Symmetry Breaking(?)
Unpolarized
0
0.5
1
0 0.05 0.1 0.15 0.2 0.25 0.3 0.35
Systematic Error
x
d_ -
u_
CTEQ5M CTEQ4M
MRST GRV98
HermesE866
Strong breaking of SU(2)-Flavor Symmetry
Polarized
-0.2
-0.15
-0.1
-0.05
0
0.05
0.1
0.15
0.2
10 -1
0.03 0.1 0.6
x
χQSMmeson cloud
x(∆u–-∆d
–)
Q2 = 2.5 GeV2
No significant breaking ofSU(2)-Flavor Symmetry ∆u ∼ ∆d
More Data needed
E.C. Aschenauer Pan Pacific, Tokyo, July 2005 19
SU(2)-Flavor Symmetry Breaking(?)
Unpolarized
0
0.5
1
0 0.05 0.1 0.15 0.2 0.25 0.3 0.35
Systematic Error
x
d_ -
u_
CTEQ5M CTEQ4M
MRST GRV98
HermesE866
Strong breaking of SU(2)-Flavor Symmetry
Polarized
-0.2
-0.15
-0.1
-0.05
0
0.05
0.1
0.15
0.2
10 -1
0.03 0.1 0.6
x
χQSMmeson cloud
x(∆u–-∆d
–)
Q2 = 2.5 GeV2
No significant breaking ofSU(2)-Flavor Symmetry ∆u ∼ ∆d
More Data needed
E.C. Aschenauer Pan Pacific, Tokyo, July 2005 19
How to measure ∆G• ”Indirect” from scaling violation
Remember unpolarized case:HERA F2
0
1
2
3
4
5
1 10 102
103
104
105
F2 em
-log
10(x
)
Q2(GeV2)
ZEUS NLO QCD fit
H1 PDF 2000 fit
H1 94-00
H1 (prel.) 99/00
ZEUS 96/97
BCDMS
E665
NMC
x=6.32E-5 x=0.000102x=0.000161
x=0.000253
x=0.0004x=0.0005
x=0.000632x=0.0008
x=0.0013
x=0.0021
x=0.0032
x=0.005
x=0.008
x=0.013
x=0.021
x=0.032
x=0.05
x=0.08
x=0.13
x=0.18
x=0.25
x=0.4
x=0.65
Remember unpolarized case:HERA F2
0
1
2
3
4
5
1 10 102
103
104
105
F2 em
-log
10(x
)
Q2(GeV2)
ZEUS NLO QCD fit
H1 PDF 2000 fit
H1 94-00
H1 (prel.) 99/00
ZEUS 96/97
BCDMS
E665
NMC
x=6.32E-5 x=0.000102x=0.000161
x=0.000253
x=0.0004x=0.0005
x=0.000632x=0.0008
x=0.0013
x=0.0021
x=0.0032
x=0.005
x=0.008
x=0.013
x=0.021
x=0.032
x=0.05
x=0.08
x=0.13
x=0.18
x=0.25
x=0.4
x=0.65
=⇒ big Q2 − xbj lever arm=⇒ very accurate G(x)
0
5
10
15
20
-410 -310 -210 -110 10
5
10
15
20
x
xg
2 = 5 GeV2Q
2 = 20 GeV2Q
2 = 200 GeV2Q
0
5
10
15
20 ZEUS-JETS (prel.) 94-00
H1 PDF 2000
total uncert.
exp. uncert.
total uncert.
H1+ZEUS
Remember unpolarized case:HERA F2
0
1
2
3
4
5
1 10 102
103
104
105
F2 em
-log
10(x
)
Q2(GeV2)
ZEUS NLO QCD fit
H1 PDF 2000 fit
H1 94-00
H1 (prel.) 99/00
ZEUS 96/97
BCDMS
E665
NMC
x=6.32E-5 x=0.000102x=0.000161
x=0.000253
x=0.0004x=0.0005
x=0.000632x=0.0008
x=0.0013
x=0.0021
x=0.0032
x=0.005
x=0.008
x=0.013
x=0.021
x=0.032
x=0.05
x=0.08
x=0.13
x=0.18
x=0.25
x=0.4
x=0.65
=⇒ big Q2 − xbj lever arm=⇒ very accurate G(x)
0
5
10
15
20
-410 -310 -210 -110 10
5
10
15
20
x
xg
2 = 5 GeV2Q
2 = 20 GeV2Q
2 = 200 GeV2Q
0
5
10
15
20 ZEUS-JETS (prel.) 94-00
H1 PDF 2000
total uncert.
exp. uncert.
total uncert.
H1+ZEUS
Polarized case:
10-4
10-3
10-2
10-1
1
10
10 2
10 3
10 4
10-1
1 10 102
E143
Q2, GeV2
HERMES
E155
EMC
SMC
• fixed target experiments=⇒ small Q2 − xbj lever arm
• determines only sign of ∆G(x)
-0.4
-0.2
0
0.2
0.4
0.6
0.8
10-3
10-2
10-1
1x
E.C. Aschenauer Pan Pacific, Tokyo, July 2005 20
How to measure ∆G• ”Indirect” from scaling violation
Remember unpolarized case:HERA F2
0
1
2
3
4
5
1 10 102
103
104
105
F2 em
-log
10(x
)
Q2(GeV2)
ZEUS NLO QCD fit
H1 PDF 2000 fit
H1 94-00
H1 (prel.) 99/00
ZEUS 96/97
BCDMS
E665
NMC
x=6.32E-5 x=0.000102x=0.000161
x=0.000253
x=0.0004x=0.0005
x=0.000632x=0.0008
x=0.0013
x=0.0021
x=0.0032
x=0.005
x=0.008
x=0.013
x=0.021
x=0.032
x=0.05
x=0.08
x=0.13
x=0.18
x=0.25
x=0.4
x=0.65
Remember unpolarized case:HERA F2
0
1
2
3
4
5
1 10 102
103
104
105
F2 em
-log
10(x
)
Q2(GeV2)
ZEUS NLO QCD fit
H1 PDF 2000 fit
H1 94-00
H1 (prel.) 99/00
ZEUS 96/97
BCDMS
E665
NMC
x=6.32E-5 x=0.000102x=0.000161
x=0.000253
x=0.0004x=0.0005
x=0.000632x=0.0008
x=0.0013
x=0.0021
x=0.0032
x=0.005
x=0.008
x=0.013
x=0.021
x=0.032
x=0.05
x=0.08
x=0.13
x=0.18
x=0.25
x=0.4
x=0.65
=⇒ big Q2 − xbj lever arm=⇒ very accurate G(x)
0
5
10
15
20
-410 -310 -210 -110 10
5
10
15
20
x
xg
2 = 5 GeV2Q
2 = 20 GeV2Q
2 = 200 GeV2Q
0
5
10
15
20 ZEUS-JETS (prel.) 94-00
H1 PDF 2000
total uncert.
exp. uncert.
total uncert.
H1+ZEUS
Remember unpolarized case:HERA F2
0
1
2
3
4
5
1 10 102
103
104
105
F2 em
-log
10(x
)
Q2(GeV2)
ZEUS NLO QCD fit
H1 PDF 2000 fit
H1 94-00
H1 (prel.) 99/00
ZEUS 96/97
BCDMS
E665
NMC
x=6.32E-5 x=0.000102x=0.000161
x=0.000253
x=0.0004x=0.0005
x=0.000632x=0.0008
x=0.0013
x=0.0021
x=0.0032
x=0.005
x=0.008
x=0.013
x=0.021
x=0.032
x=0.05
x=0.08
x=0.13
x=0.18
x=0.25
x=0.4
x=0.65
=⇒ big Q2 − xbj lever arm=⇒ very accurate G(x)
0
5
10
15
20
-410 -310 -210 -110 10
5
10
15
20
x
xg
2 = 5 GeV2Q
2 = 20 GeV2Q
2 = 200 GeV2Q
0
5
10
15
20 ZEUS-JETS (prel.) 94-00
H1 PDF 2000
total uncert.
exp. uncert.
total uncert.
H1+ZEUS
Polarized case:
10-4
10-3
10-2
10-1
1
10
10 2
10 3
10 4
10-1
1 10 102
E143
Q2, GeV2
HERMES
E155
EMC
SMC
• fixed target experiments=⇒ small Q2 − xbj lever arm
• determines only sign of ∆G(x)
-0.4
-0.2
0
0.2
0.4
0.6
0.8
10-3
10-2
10-1
1x
E.C. Aschenauer Pan Pacific, Tokyo, July 2005 20
How to measure ∆G• ”Indirect” from scaling violation
Remember unpolarized case:HERA F2
0
1
2
3
4
5
1 10 102
103
104
105
F2 em
-log
10(x
)
Q2(GeV2)
ZEUS NLO QCD fit
H1 PDF 2000 fit
H1 94-00
H1 (prel.) 99/00
ZEUS 96/97
BCDMS
E665
NMC
x=6.32E-5 x=0.000102x=0.000161
x=0.000253
x=0.0004x=0.0005
x=0.000632x=0.0008
x=0.0013
x=0.0021
x=0.0032
x=0.005
x=0.008
x=0.013
x=0.021
x=0.032
x=0.05
x=0.08
x=0.13
x=0.18
x=0.25
x=0.4
x=0.65
Remember unpolarized case:HERA F2
0
1
2
3
4
5
1 10 102
103
104
105
F2 em
-log
10(x
)
Q2(GeV2)
ZEUS NLO QCD fit
H1 PDF 2000 fit
H1 94-00
H1 (prel.) 99/00
ZEUS 96/97
BCDMS
E665
NMC
x=6.32E-5 x=0.000102x=0.000161
x=0.000253
x=0.0004x=0.0005
x=0.000632x=0.0008
x=0.0013
x=0.0021
x=0.0032
x=0.005
x=0.008
x=0.013
x=0.021
x=0.032
x=0.05
x=0.08
x=0.13
x=0.18
x=0.25
x=0.4
x=0.65
=⇒ big Q2 − xbj lever arm=⇒ very accurate G(x)
0
5
10
15
20
-410 -310 -210 -110 10
5
10
15
20
x
xg
2 = 5 GeV2Q
2 = 20 GeV2Q
2 = 200 GeV2Q
0
5
10
15
20 ZEUS-JETS (prel.) 94-00
H1 PDF 2000
total uncert.
exp. uncert.
total uncert.
H1+ZEUS
Remember unpolarized case:HERA F2
0
1
2
3
4
5
1 10 102
103
104
105
F2 em
-log
10(x
)
Q2(GeV2)
ZEUS NLO QCD fit
H1 PDF 2000 fit
H1 94-00
H1 (prel.) 99/00
ZEUS 96/97
BCDMS
E665
NMC
x=6.32E-5 x=0.000102x=0.000161
x=0.000253
x=0.0004x=0.0005
x=0.000632x=0.0008
x=0.0013
x=0.0021
x=0.0032
x=0.005
x=0.008
x=0.013
x=0.021
x=0.032
x=0.05
x=0.08
x=0.13
x=0.18
x=0.25
x=0.4
x=0.65
=⇒ big Q2 − xbj lever arm=⇒ very accurate G(x)
0
5
10
15
20
-410 -310 -210 -110 10
5
10
15
20
x
xg
2 = 5 GeV2Q
2 = 20 GeV2Q
2 = 200 GeV2Q
0
5
10
15
20 ZEUS-JETS (prel.) 94-00
H1 PDF 2000
total uncert.
exp. uncert.
total uncert.
H1+ZEUS
Polarized case:
10-4
10-3
10-2
10-1
1
10
10 2
10 3
10 4
10-1
1 10 102
E143
Q2, GeV2
HERMES
E155
EMC
SMC
• fixed target experiments=⇒ small Q2 − xbj lever arm
• determines only sign of ∆G(x)
-0.4
-0.2
0
0.2
0.4
0.6
0.8
10-3
10-2
10-1
1x
E.C. Aschenauer Pan Pacific, Tokyo, July 2005 20
How to measure ∆G• ”Indirect” from scaling violation
Remember unpolarized case:HERA F2
0
1
2
3
4
5
1 10 102
103
104
105
F2 em
-log
10(x
)
Q2(GeV2)
ZEUS NLO QCD fit
H1 PDF 2000 fit
H1 94-00
H1 (prel.) 99/00
ZEUS 96/97
BCDMS
E665
NMC
x=6.32E-5 x=0.000102x=0.000161
x=0.000253
x=0.0004x=0.0005
x=0.000632x=0.0008
x=0.0013
x=0.0021
x=0.0032
x=0.005
x=0.008
x=0.013
x=0.021
x=0.032
x=0.05
x=0.08
x=0.13
x=0.18
x=0.25
x=0.4
x=0.65
Remember unpolarized case:HERA F2
0
1
2
3
4
5
1 10 102
103
104
105
F2 em
-log
10(x
)
Q2(GeV2)
ZEUS NLO QCD fit
H1 PDF 2000 fit
H1 94-00
H1 (prel.) 99/00
ZEUS 96/97
BCDMS
E665
NMC
x=6.32E-5 x=0.000102x=0.000161
x=0.000253
x=0.0004x=0.0005
x=0.000632x=0.0008
x=0.0013
x=0.0021
x=0.0032
x=0.005
x=0.008
x=0.013
x=0.021
x=0.032
x=0.05
x=0.08
x=0.13
x=0.18
x=0.25
x=0.4
x=0.65
=⇒ big Q2 − xbj lever arm=⇒ very accurate G(x)
0
5
10
15
20
-410 -310 -210 -110 10
5
10
15
20
x
xg
2 = 5 GeV2Q
2 = 20 GeV2Q
2 = 200 GeV2Q
0
5
10
15
20 ZEUS-JETS (prel.) 94-00
H1 PDF 2000
total uncert.
exp. uncert.
total uncert.
H1+ZEUS
Remember unpolarized case:HERA F2
0
1
2
3
4
5
1 10 102
103
104
105
F2 em
-log
10(x
)
Q2(GeV2)
ZEUS NLO QCD fit
H1 PDF 2000 fit
H1 94-00
H1 (prel.) 99/00
ZEUS 96/97
BCDMS
E665
NMC
x=6.32E-5 x=0.000102x=0.000161
x=0.000253
x=0.0004x=0.0005
x=0.000632x=0.0008
x=0.0013
x=0.0021
x=0.0032
x=0.005
x=0.008
x=0.013
x=0.021
x=0.032
x=0.05
x=0.08
x=0.13
x=0.18
x=0.25
x=0.4
x=0.65
=⇒ big Q2 − xbj lever arm=⇒ very accurate G(x)
0
5
10
15
20
-410 -310 -210 -110 10
5
10
15
20
x
xg
2 = 5 GeV2Q
2 = 20 GeV2Q
2 = 200 GeV2Q
0
5
10
15
20 ZEUS-JETS (prel.) 94-00
H1 PDF 2000
total uncert.
exp. uncert.
total uncert.
H1+ZEUS
Polarized case:
10-4
10-3
10-2
10-1
1
10
10 2
10 3
10 4
10-1
1 10 102
E143
Q2, GeV2
HERMES
E155
EMC
SMC
• fixed target experiments=⇒ small Q2 − xbj lever arm
• determines only sign of ∆G(x)
-0.4
-0.2
0
0.2
0.4
0.6
0.8
10-3
10-2
10-1
1x
E.C. Aschenauer Pan Pacific, Tokyo, July 2005 20
Direct Measurements of ∆G/G
Isolate the photon-gluon fusion process (PGF)
• Select pairs of high-PT oppositely charged hadronsOR
Select single high-PT hadrons
• Reaction: γ∗p → h±1 + h∓2 + X OR γ∗p → h±1 + X
• A|| =N
→⇐h
±1h
∓2
−N→⇒h
±1h
∓2
N→⇐h
±1h
∓2
+ N→⇒h
±1h
∓2
vs. pT(h±1 ,h∓2 ); A|| =N
→⇐h
±1
− N→⇒h
±1
N→⇐h
±1
+ N→⇒h
±1
vs. pT(h±1 )
• low Q2 range (Q2 > 0 GeV2)=⇒ increase statistics=⇒ scale of hard sub-processes p2
T
• require pT (h1,h2) > 0.5 GeV,M(2π) > 1.0 GeV =⇒ removes resonances ρ and φ
E.C. Aschenauer Pan Pacific, Tokyo, July 2005 21
Direct Measurements of ∆G/G
Isolate the photon-gluon fusion process (PGF)
• Select pairs of high-PT oppositely charged hadronsOR
Select single high-PT hadrons
• Reaction: γ∗p → h±1 + h∓2 + X OR γ∗p → h±1 + X
• A|| =N
→⇐h
±1h
∓2
−N→⇒h
±1h
∓2
N→⇐h
±1h
∓2
+ N→⇒h
±1h
∓2
vs. pT(h±1 ,h∓2 ); A|| =N
→⇐h
±1
− N→⇒h
±1
N→⇐h
±1
+ N→⇒h
±1
vs. pT(h±1 )
• low Q2 range (Q2 > 0 GeV2)=⇒ increase statistics=⇒ scale of hard sub-processes p2
T
• require pT (h1,h2) > 0.5 GeV,M(2π) > 1.0 GeV =⇒ removes resonances ρ and φ
E.C. Aschenauer Pan Pacific, Tokyo, July 2005 21
Interpretation ?!
Four different processes can contribute:
γ
T T
e+
e+’
’
q
V
h,v
*q
h,
q
+
−
l
−
+
lt
VMDAVMD = 0 DIS
ADIS ∼ ∆q
q
QCDC
AQCDC ∼ ∆q
q
PGF
APGF ∼ ∆G
G
A‖ ∼4∑
i=1
fi ·Ai ∼ (fQCDCAQCDC + fPGFAPGF + fDISADIS + fXAX)
APGF ≈ 〈a(γg → qq)〉⟨∆G
G
⟩= 〈aPGF〉
︸ ︷︷ ︸
⟨∆G
G
⟩
-1
AQCDC ≈ 〈a(γq → qg)〉⟨∆q
q
⟩= 〈aQCDC〉
︸ ︷︷ ︸
⟨∆q
q
⟩
+ 12
.. estimate theirrelative contributions fi
using Monte Carlo (PYTHIA-6)=⇒ ∆G/G
E.C. Aschenauer Pan Pacific, Tokyo, July 2005 22
Interpretation ?!
Four different processes can contribute:
γ
T T
e+
e+’
’
q
V
h,v
*q
h,
q
+
−
l
−
+
lt
VMDAVMD = 0 DIS
ADIS ∼ ∆q
q
QCDC
AQCDC ∼ ∆q
q
PGF
APGF ∼ ∆G
G
A‖ ∼4∑
i=1
fi ·Ai ∼ (fQCDCAQCDC + fPGFAPGF + fDISADIS + fXAX)
APGF ≈ 〈a(γg → qq)〉⟨∆G
G
⟩= 〈aPGF〉
︸ ︷︷ ︸
⟨∆G
G
⟩
-1
AQCDC ≈ 〈a(γq → qg)〉⟨∆q
q
⟩= 〈aQCDC〉
︸ ︷︷ ︸
⟨∆q
q
⟩
+ 12
.. estimate theirrelative contributions fi
using Monte Carlo (PYTHIA-6)=⇒ ∆G/G
E.C. Aschenauer Pan Pacific, Tokyo, July 2005 22
Interpretation ?!
Four different processes can contribute:
γ
T T
e+
e+’
’
q
V
h,v
*q
h,
q
+
−
l
−
+
lt
VMDAVMD = 0 DIS
ADIS ∼ ∆q
q
QCDC
AQCDC ∼ ∆q
q
PGF
APGF ∼ ∆G
G
A‖ ∼4∑
i=1
fi ·Ai ∼ (fQCDCAQCDC + fPGFAPGF + fDISADIS + fXAX)
APGF ≈ 〈a(γg → qq)〉⟨∆G
G
⟩= 〈aPGF〉
︸ ︷︷ ︸
⟨∆G
G
⟩
-1
AQCDC ≈ 〈a(γq → qg)〉⟨∆q
q
⟩= 〈aQCDC〉
︸ ︷︷ ︸
⟨∆q
q
⟩
+ 12
.. estimate theirrelative contributions fi
using Monte Carlo (PYTHIA-6)=⇒ ∆G/G
E.C. Aschenauer Pan Pacific, Tokyo, July 2005 22
Interpretation ?!
Four different processes can contribute:
γ
T T
e+
e+’
’
q
V
h,v
*q
h,
q
+
−
l
−
+
lt
VMDAVMD = 0 DIS
ADIS ∼ ∆q
q
QCDC
AQCDC ∼ ∆q
q
PGF
APGF ∼ ∆G
G
A‖ ∼4∑
i=1
fi ·Ai ∼ (fQCDCAQCDC + fPGFAPGF + fDISADIS + fXAX)
APGF ≈ 〈a(γg → qq)〉⟨∆G
G
⟩= 〈aPGF〉
︸ ︷︷ ︸
⟨∆G
G
⟩
-1
AQCDC ≈ 〈a(γq → qg)〉⟨∆q
q
⟩= 〈aQCDC〉
︸ ︷︷ ︸
⟨∆q
q
⟩
+ 12
.. estimate theirrelative contributions fi
using Monte Carlo (PYTHIA-6)=⇒ ∆G/G
E.C. Aschenauer Pan Pacific, Tokyo, July 2005 22
Pairs of high-PT Hadrons
pTh2 (GeV/c)
f i (i =
QC
DC
, PG
F, V
MD
)pT
h1>1.5 GeV/c
fPGF
fQCDC
fVMD
0
0.2
0.4
0.6
0.8
1
0.6 0.8 1 1.2 1.4 1.6 1.8-1
-0.8
-0.6
-0.4
-0.2
0
0.2
0.4
0.6
0.6 0.8 1 1.2 1.4 1.6 1.8 2
GSA (<∆G/G> ~ 0.4)GSB (<∆G/G> ~ 0.3)GSC (<∆G/G> ~ -0.1)
pTh2 (GeV/c)
A||(
pTh
1 ,pTh
2 )
pTh1>1.5 GeV/c ∆G/G=-1
∆G/G=0
∆G/G=+1
∆G/G=0.41
Published: within LO pQCD and PYTHIA5 MC model
∆G/G = 0.41 ± 0.18 (stat.) ± 0.03 (exp.syst.)
at 〈xG〉 = 0.17 and 〈p2T 〉 = 2.1 GeV2
6 x more data on polarized Deuterium and new Pythia modified for HERMES
SMC Q2 > 1 GeV2
COMPASS Q2 < 1 GeV2
COMPASS Q2 > 1 GeV2
HERMES Q2 << 0.1 GeV2
HERMES Q2 << 0.1 GeV2 target H/D
HERMES all Q2 GeV2
HERMES Q2 > 0.1 GeV2
-0.6
-0.4
-0.2
0
0.2
0.4
0.6
10-2
10-1
Extraction still Model dependent
E.C. Aschenauer Pan Pacific, Tokyo, July 2005 23
Pairs of high-PT Hadrons
pTh2 (GeV/c)
f i (i =
QC
DC
, PG
F, V
MD
)pT
h1>1.5 GeV/c
fPGF
fQCDC
fVMD
0
0.2
0.4
0.6
0.8
1
0.6 0.8 1 1.2 1.4 1.6 1.8-1
-0.8
-0.6
-0.4
-0.2
0
0.2
0.4
0.6
0.6 0.8 1 1.2 1.4 1.6 1.8 2
GSA (<∆G/G> ~ 0.4)GSB (<∆G/G> ~ 0.3)GSC (<∆G/G> ~ -0.1)
pTh2 (GeV/c)
A||(
pTh
1 ,pTh
2 )
pTh1>1.5 GeV/c ∆G/G=-1
∆G/G=0
∆G/G=+1
∆G/G=0.41
Published: within LO pQCD and PYTHIA5 MC model
∆G/G = 0.41 ± 0.18 (stat.) ± 0.03 (exp.syst.)
at 〈xG〉 = 0.17 and 〈p2T 〉 = 2.1 GeV2
6 x more data on polarized Deuterium and new Pythia modified for HERMES
SMC Q2 > 1 GeV2
COMPASS Q2 < 1 GeV2
COMPASS Q2 > 1 GeV2
HERMES Q2 << 0.1 GeV2
HERMES Q2 << 0.1 GeV2 target H/D
HERMES all Q2 GeV2
HERMES Q2 > 0.1 GeV2
-0.6
-0.4
-0.2
0
0.2
0.4
0.6
10-2
10-1
Extraction still Model dependent
E.C. Aschenauer Pan Pacific, Tokyo, July 2005 23
Why is a FF extraction important for HERMES
• enter in ∆q, δq and f⊥1T extraction
• test factorization at HERMESenergies
√s ∼ 7GeV
• are the FF from e+e− applicable at ep
and/or⟨Q2
⟩= 2.5GeV
Extract π,K,p multiplicities:
1
NDIS· dNh(z,Q2)
dz=
∑
f
e2f
∫ 1
0dxqf (x,Q2)Dh
f (z,Q2)
∑
f
e2f
∫ 1
0dxqf (x,Q2)
E.C. Aschenauer Pan Pacific, Tokyo, July 2005 24
Why is a FF extraction important for HERMES
• enter in ∆q, δq and f⊥1T extraction
• test factorization at HERMESenergies
√s ∼ 7GeV
• are the FF from e+e− applicable at ep
and/or⟨Q2
⟩= 2.5GeV
Extract π,K,p multiplicities:
1
NDIS· dNh(z,Q2)
dz=
∑
f
e2f
∫ 1
0dxqf (x,Q2)Dh
f (z,Q2)
∑
f
e2f
∫ 1
0dxqf (x,Q2)
E.C. Aschenauer Pan Pacific, Tokyo, July 2005 24
How to extract FF/Multiplicities at HERMESunpolarisedH & D data
experimentalmultiplicitiesin acceptance
unpolarisedH & D data
e+
e−c.s. background
correction
experimentalmultiplicitiesin acceptance
γ
T T
e+
e+’
’
q
V
h,v
*q
h,
q
+
−
l
−
+
lt
excl. VM correction
PID using RICH
MC
unpolarisedH & D data
e+
e−c.s. background
correction
experimentalmultiplicitiesin acceptance
born levelmultiplicities
γ
T T
e+
e+’
’
q
V
h,v
*q
h,
q
+
−
l
−
+
lt
excl. VM correction
PID using RICH
MC
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16Born level z bin (j)
Exp
erim
enta
l bin
(i)
n(i,j) for all pions
0.04
0.05
0.060.070.080.090.1
0.2
0.3
0.4
0.5
0.60.70.80.9
1
2
0 20 40 60 80 100
Q2 (GeV2/c2)
Du
π+ in
PK
H p
aram
etri
sati
on
z = 0.3
z = 0.7
LONLO
unpolarisedH & D data
e+
e−c.s. background
correction
experimentalmultiplicitiesin acceptance
born levelmultiplicities
Q − Evolution2
acceptance correctionradiative unfolding
γ
T T
e+
e+’
’
q
V
h,v
*q
h,
q
+
−
l
−
+
lt
excl. VM correction
PID using RICH
MC
E.C. Aschenauer Pan Pacific, Tokyo, July 2005 25
How to extract FF/Multiplicities at HERMES
unpolarisedH & D data
experimentalmultiplicitiesin acceptance
unpolarisedH & D data
e+
e−c.s. background
correction
experimentalmultiplicitiesin acceptance
γ
T T
e+
e+’
’
q
V
h,v
*q
h,
q
+
−
l
−
+
lt
excl. VM correction
PID using RICH
MC
unpolarisedH & D data
e+
e−c.s. background
correction
experimentalmultiplicitiesin acceptance
born levelmultiplicities
γ
T T
e+
e+’
’
q
V
h,v
*q
h,
q
+
−
l
−
+
lt
excl. VM correction
PID using RICH
MC
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16Born level z bin (j)
Exp
erim
enta
l bin
(i)
n(i,j) for all pions
0.04
0.05
0.060.070.080.090.1
0.2
0.3
0.4
0.5
0.60.70.80.9
1
2
0 20 40 60 80 100
Q2 (GeV2/c2)
Du
π+ in
PK
H p
aram
etri
sati
on
z = 0.3
z = 0.7
LONLO
unpolarisedH & D data
e+
e−c.s. background
correction
experimentalmultiplicitiesin acceptance
born levelmultiplicities
Q − Evolution2
acceptance correctionradiative unfolding
γ
T T
e+
e+’
’
q
V
h,v
*q
h,
q
+
−
l
−
+
lt
excl. VM correction
PID using RICH
MC
E.C. Aschenauer Pan Pacific, Tokyo, July 2005 25
How to extract FF/Multiplicities at HERMES
unpolarisedH & D data
experimentalmultiplicitiesin acceptance
unpolarisedH & D data
e+
e−c.s. background
correction
experimentalmultiplicitiesin acceptance
γ
T T
e+
e+’
’
q
V
h,v
*q
h,
q
+
−
l
−
+
lt
excl. VM correction
PID using RICH
MC
unpolarisedH & D data
e+
e−c.s. background
correction
experimentalmultiplicitiesin acceptance
born levelmultiplicities
γ
T T
e+
e+’
’
q
V
h,v
*q
h,
q
+
−
l
−
+
lt
excl. VM correction
PID using RICH
MC
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16Born level z bin (j)
Exp
erim
enta
l bin
(i)
n(i,j) for all pions
0.04
0.05
0.060.070.080.090.1
0.2
0.3
0.4
0.5
0.60.70.80.9
1
2
0 20 40 60 80 100
Q2 (GeV2/c2)
Du
π+ in
PK
H p
aram
etri
sati
on
z = 0.3
z = 0.7
LONLO
unpolarisedH & D data
e+
e−c.s. background
correction
experimentalmultiplicitiesin acceptance
born levelmultiplicities
Q − Evolution2
acceptance correctionradiative unfolding
γ
T T
e+
e+’
’
q
V
h,v
*q
h,
q
+
−
l
−
+
lt
excl. VM correction
PID using RICH
MC
E.C. Aschenauer Pan Pacific, Tokyo, July 2005 25
How to extract FF/Multiplicities at HERMES
unpolarisedH & D data
experimentalmultiplicitiesin acceptance
unpolarisedH & D data
e+
e−c.s. background
correction
experimentalmultiplicitiesin acceptance
γ
T T
e+
e+’
’
q
V
h,v
*q
h,
q
+
−
l
−
+
lt
excl. VM correction
PID using RICH
MC
unpolarisedH & D data
e+
e−c.s. background
correction
experimentalmultiplicitiesin acceptance
born levelmultiplicities
γ
T T
e+
e+’
’
q
V
h,v
*q
h,
q
+
−
l
−
+
lt
excl. VM correction
PID using RICH
MC
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16Born level z bin (j)
Exp
erim
enta
l bin
(i)
n(i,j) for all pions
0.04
0.05
0.060.070.080.09
0.1
0.2
0.3
0.4
0.5
0.60.70.80.9
1
2
0 20 40 60 80 100
Q2 (GeV2/c2)
Du
π+ in
PK
H p
aram
etri
sati
on
z = 0.3
z = 0.7
LONLO
unpolarisedH & D data
e+
e−c.s. background
correction
experimentalmultiplicitiesin acceptance
born levelmultiplicities
Q − Evolution2
acceptance correctionradiative unfolding
γ
T T
e+
e+’
’
q
V
h,v
*q
h,
q
+
−
l
−
+
lt
excl. VM correction
PID using RICH
MC
E.C. Aschenauer Pan Pacific, Tokyo, July 2005 25
Data - MC Agreement• MC: Lepto in combination with JETSET; PDF: CTEQ-6L
Fragmentation parameters tuned to HERMES multiplicities in acceptance
• Data: Q2 > 1GeV2,W2 > 10GeV2, z > 0.2,2GeV < p(π,K,p)± < 15GeV
PID and background corrections as described before applied
0
0.1
0.2
0.3
0 0.25 0.5 0.75 1 1.25
pt
Mu
ltip
licit
y
pip
0
0.1
0.2
0.3
0 0.25 0.5 0.75 1 1.25
pt
Mu
ltip
licit
y
pim
0
0.02
0.04
0.06
0 0.25 0.5 0.75 1 1.25
pt
Mu
ltip
licit
y
kp
0
0.01
0.02
0.03
0 0.25 0.5 0.75 1 1.25
pt
Mu
ltip
licit
y
km
0
0.05
0.1
0.15
0 0.25 0.5 0.75 1 1.25
pt
Mu
ltip
licit
y
pp
0
0.005
0.01
0.015
0 0.25 0.5 0.75 1 1.25
pt
Mu
ltip
licit
y
pm
Exp.
2004c
2004a
F. all W2
Jetset
0
0.02
0.04
0.06
0.08
0.1
0 1 2 3
rap
Mu
ltip
licit
y
pip
0
0.02
0.04
0.06
0.08
0.1
0 1 2 3
rap
Mu
ltip
licit
y
pim
0
0.01
0.02
0.03
0.04
0 1 2 3
rap
Mu
ltip
licit
y
kp
0
0.005
0.01
0.015
0.02
0 1 2 3
rap
Mu
ltip
licit
y
km
0
0.02
0.04
0.06
0.08
0.1
0 1 2 3
rap
Mu
ltip
licit
y
pp
0
0.002
0.004
0.006
0 1 2 3
rap
Mu
ltip
licit
y
pm
Exp.
2004c
2004a
F. all W2
Jetset
Excellent agreement; also on cross section level (Data/MC < 10%)
E.C. Aschenauer Pan Pacific, Tokyo, July 2005 26
Data - MC Agreement• MC: Lepto in combination with JETSET; PDF: CTEQ-6L
Fragmentation parameters tuned to HERMES multiplicities in acceptance
• Data: Q2 > 1GeV2,W2 > 10GeV2, z > 0.2,2GeV < p(π,K,p)± < 15GeV
PID and background corrections as described before applied
0
0.1
0.2
0.3
0 0.25 0.5 0.75 1 1.25
pt
Mu
ltip
licit
y
pip
0
0.1
0.2
0.3
0 0.25 0.5 0.75 1 1.25
pt
Mu
ltip
licit
y
pim
0
0.02
0.04
0.06
0 0.25 0.5 0.75 1 1.25
pt
Mu
ltip
licit
y
kp
0
0.01
0.02
0.03
0 0.25 0.5 0.75 1 1.25
pt
Mu
ltip
licit
y
km
0
0.05
0.1
0.15
0 0.25 0.5 0.75 1 1.25
pt
Mu
ltip
licit
y
pp
0
0.005
0.01
0.015
0 0.25 0.5 0.75 1 1.25
pt
Mu
ltip
licit
y
pm
Exp.
2004c
2004a
F. all W2
Jetset
0
0.02
0.04
0.06
0.08
0.1
0 1 2 3
rap
Mu
ltip
licit
y
pip
0
0.02
0.04
0.06
0.08
0.1
0 1 2 3
rap
Mu
ltip
licit
y
pim
0
0.01
0.02
0.03
0.04
0 1 2 3
rap
Mu
ltip
licit
y
kp
0
0.005
0.01
0.015
0.02
0 1 2 3
rap
Mu
ltip
licit
y
km
0
0.02
0.04
0.06
0.08
0.1
0 1 2 3
rap
Mu
ltip
licit
y
pp
0
0.002
0.004
0.006
0 1 2 3
rap
Mu
ltip
licit
y
pm
Exp.
2004c
2004a
F. all W2
Jetset
Excellent agreement; also on cross section level (Data/MC < 10%)
E.C. Aschenauer Pan Pacific, Tokyo, July 2005 26
Exclusive VM Contamination
• exclusive VM production:totally different process than SIDIS
• estimate contribution from PYTHIA-6:changes: QED-radiation, VMD-model,...
• ratio: Nhexcl.VM(z)/Nh
SIDIS(z)
• large contribution for π at high zcontribution for K moderate vs z
• contribution growing for small xbj forboth π and K
00.5
11.5
22.5
33.5
44.5
0 5 10 15
∆E (GeV)
σ (p
b)
00.20.40.60.8
11.21.41.61.8
2
0 5 10 15
∆E (GeV)
σ Dat
a/σ M
C
0
0.2
0.4
0.6
0.8
1
1.2
0.4 0.6 0.8 1
M(π+π-) (GeV)
σ (p
b)
00.20.40.60.8
11.21.41.61.8
2
0.4 0.6 0.8 1
M(π+π-) (GeV)
σ Dat
a/σ M
C
zN
h V
M(z
)/N
h(z
)
0
0.2
0.4
0.6
0 0.1 0.2 0.3 0.4 0.5 0.6 0.7 0.8 0.9 1
0
0.2
0.4
0.6
0 0.1 0.2 0.3 0.4 0.5 0.6 0.7 0.8 0.9 1
π+Target:
ProtonNeutronDeuterium
0
0.2
0.4
0.6
0.8
0 0.1 0.2 0.3 0.4 0.5 0.6 0.7 0.8 0.9 1
0
0.2
0.4
0.6
0.8
0 0.1 0.2 0.3 0.4 0.5 0.6 0.7 0.8 0.9 1
π-
0
0.025
0.05
0.075
0.1
0 0.1 0.2 0.3 0.4 0.5 0.6 0.7 0.8 0.9 1
0
0.025
0.05
0.075
0.1
0 0.1 0.2 0.3 0.4 0.5 0.6 0.7 0.8 0.9 1
K+
0
0.1
0.2
0.3
0.4
0 0.1 0.2 0.3 0.4 0.5 0.6 0.7 0.8 0.9 10
0.1
0.2
0.3
0.4
0 0.1 0.2 0.3 0.4 0.5 0.6 0.7 0.8 0.9 1
K-
xBjN
h V
M(x
Bj)/
Nh(x
Bj)
0
0.2
0.4
0.6
10 -1 1
0
0.2
0.4
0.6
10-1
1
π+Target:
ProtonNeutronDeuterium
0.25 < z < 0.350.60 < z < 0.75
0
0.2
0.4
0.6
10-1
1
0
0.2
0.4
0.6
10-1
1
π-
0
0.025
0.05
0.075
0.1
10-1
1
0
0.025
0.05
0.075
0.1
10-1
1
K+
0
0.025
0.05
0.075
0.1
10-1
10
0.025
0.05
0.075
0.1
10-1
1
K-
E.C. Aschenauer Pan Pacific, Tokyo, July 2005 27
Exclusive VM Contamination
• exclusive VM production:totally different process than SIDIS
• estimate contribution from PYTHIA-6:changes: QED-radiation, VMD-model,...
• ratio: Nhexcl.VM(z)/Nh
SIDIS(z)
• large contribution for π at high zcontribution for K moderate vs z
• contribution growing for small xbj forboth π and K
00.5
11.5
22.5
33.5
44.5
0 5 10 15
∆E (GeV)
σ (p
b)
00.20.40.60.8
11.21.41.61.8
2
0 5 10 15
∆E (GeV)
σ Dat
a/σ M
C
0
0.2
0.4
0.6
0.8
1
1.2
0.4 0.6 0.8 1
M(π+π-) (GeV)
σ (p
b)
00.20.40.60.8
11.21.41.61.8
2
0.4 0.6 0.8 1
M(π+π-) (GeV)
σ Dat
a/σ M
C
zN
h V
M(z
)/N
h(z
)
0
0.2
0.4
0.6
0 0.1 0.2 0.3 0.4 0.5 0.6 0.7 0.8 0.9 1
0
0.2
0.4
0.6
0 0.1 0.2 0.3 0.4 0.5 0.6 0.7 0.8 0.9 1
π+Target:
ProtonNeutronDeuterium
0
0.2
0.4
0.6
0.8
0 0.1 0.2 0.3 0.4 0.5 0.6 0.7 0.8 0.9 1
0
0.2
0.4
0.6
0.8
0 0.1 0.2 0.3 0.4 0.5 0.6 0.7 0.8 0.9 1
π-
0
0.025
0.05
0.075
0.1
0 0.1 0.2 0.3 0.4 0.5 0.6 0.7 0.8 0.9 1
0
0.025
0.05
0.075
0.1
0 0.1 0.2 0.3 0.4 0.5 0.6 0.7 0.8 0.9 1
K+
0
0.1
0.2
0.3
0.4
0 0.1 0.2 0.3 0.4 0.5 0.6 0.7 0.8 0.9 10
0.1
0.2
0.3
0.4
0 0.1 0.2 0.3 0.4 0.5 0.6 0.7 0.8 0.9 1
K-
xBj
Nh V
M(x
Bj)/
Nh(x
Bj)
0
0.2
0.4
0.6
10 -1 1
0
0.2
0.4
0.6
10-1
1
π+Target:
ProtonNeutronDeuterium
0.25 < z < 0.350.60 < z < 0.75
0
0.2
0.4
0.6
10-1
1
0
0.2
0.4
0.6
10-1
1
π-
0
0.025
0.05
0.075
0.1
10-1
1
0
0.025
0.05
0.075
0.1
10-1
1
K+
0
0.025
0.05
0.075
0.1
10-1
10
0.025
0.05
0.075
0.1
10-1
1
K-
E.C. Aschenauer Pan Pacific, Tokyo, July 2005 27
Exclusive VM Contamination
• exclusive VM production:totally different process than SIDIS
• estimate contribution from PYTHIA-6:changes: QED-radiation, VMD-model,...
• ratio: Nhexcl.VM(z)/Nh
SIDIS(z)
• large contribution for π at high zcontribution for K moderate vs z
• contribution growing for small xbj forboth π and K
00.5
11.5
22.5
33.5
44.5
0 5 10 15
∆E (GeV)
σ (p
b)
00.20.40.60.8
11.21.41.61.8
2
0 5 10 15
∆E (GeV)
σ Dat
a/σ M
C
0
0.2
0.4
0.6
0.8
1
1.2
0.4 0.6 0.8 1
M(π+π-) (GeV)
σ (p
b)
00.20.40.60.8
11.21.41.61.8
2
0.4 0.6 0.8 1
M(π+π-) (GeV)
σ Dat
a/σ M
C
zN
h V
M(z
)/N
h(z
)
0
0.2
0.4
0.6
0 0.1 0.2 0.3 0.4 0.5 0.6 0.7 0.8 0.9 1
0
0.2
0.4
0.6
0 0.1 0.2 0.3 0.4 0.5 0.6 0.7 0.8 0.9 1
π+Target:
ProtonNeutronDeuterium
0
0.2
0.4
0.6
0.8
0 0.1 0.2 0.3 0.4 0.5 0.6 0.7 0.8 0.9 1
0
0.2
0.4
0.6
0.8
0 0.1 0.2 0.3 0.4 0.5 0.6 0.7 0.8 0.9 1
π-
0
0.025
0.05
0.075
0.1
0 0.1 0.2 0.3 0.4 0.5 0.6 0.7 0.8 0.9 1
0
0.025
0.05
0.075
0.1
0 0.1 0.2 0.3 0.4 0.5 0.6 0.7 0.8 0.9 1
K+
0
0.1
0.2
0.3
0.4
0 0.1 0.2 0.3 0.4 0.5 0.6 0.7 0.8 0.9 10
0.1
0.2
0.3
0.4
0 0.1 0.2 0.3 0.4 0.5 0.6 0.7 0.8 0.9 1
K-
xBjN
h V
M(x
Bj)/
Nh(x
Bj)
0
0.2
0.4
0.6
10 -1 1
0
0.2
0.4
0.6
10-1
1
π+Target:
ProtonNeutronDeuterium
0.25 < z < 0.350.60 < z < 0.75
0
0.2
0.4
0.6
10-1
1
0
0.2
0.4
0.6
10-1
1
π-
0
0.025
0.05
0.075
0.1
10-1
1
0
0.025
0.05
0.075
0.1
10-1
1
K+
0
0.025
0.05
0.075
0.1
10-1
10
0.025
0.05
0.075
0.1
10-1
1
K-
E.C. Aschenauer Pan Pacific, Tokyo, July 2005 27
π± - Multiplicity vs. z
10-2
10-1
1
0 0.1 0.2 0.3 0.4 0.5 0.6 0.7 0.8 0.9 1z
mu
ltip
licit
y
HERMES Preliminary
π+
excl. VM substractedexcl. VM included
proton target
Q2=2.5 GeV2/c2
10-2
10-1
1
0 0.1 0.2 0.3 0.4 0.5 0.6 0.7 0.8 0.9 1z
mu
ltip
licit
y
HERMES Preliminary
π-
excl. VM substractedexcl. VM included
proton target
Q2=2.5 GeV2/c2
• Systematic uncertainty mainly from hadron PID correction
• Q2 > 1GeV2,W2 > 10GeV2
E.C. Aschenauer Pan Pacific, Tokyo, July 2005 28
π± - Multiplicity vs. z
10-2
10-1
1
0 0.1 0.2 0.3 0.4 0.5 0.6 0.7 0.8 0.9 1z
mu
ltip
licit
y
HERMES Preliminary
π+
excl. VM substractedexcl. VM includedEMC D(u→π+) FF
proton target
Q2=25.0 GeV2/c2
10-3
10-2
10-1
1
0 0.1 0.2 0.3 0.4 0.5 0.6 0.7 0.8 0.9 1z
mu
ltip
licit
y
HERMES Preliminary
π-
excl. VM substractedexcl. VM includedEMC D(u→π-) FF
proton target
Q2=25.0 GeV2/c2
• Comparison with EMC, Nucl. Phys. B321 (1989) 541
• EMC: Fragmentation Function Dπ±
u
E.C. Aschenauer Pan Pacific, Tokyo, July 2005 29
π± - Multiplicity vs. Q2 and xbj
10-1
1
1 10 Q2
(d2 N
π /dz
dQ
2 ) / (
dN
dis
/dQ
2 )
: 0.25 < z < 0.35: 0.35 < z < 0.45
: 0.45 < z < 0.60: 0.60 < z < 0.75
HERMES Preliminary
π+/-
excl. VM substractedexcl. VM included
Kretzer FF
proton target
10-1
1
10
10-1
1xbj(d
2 (N
π++N
π-)
/dz
dx)
/ (d
Nd
is/d
x)
: 0.25 < z < 0.35: 0.35 < z < 0.45
: 0.45 < z < 0.60: 0.60 < z < 0.75
HERMES 2000 Preliminary
π
excl. VM substractedexcl. VM includedEMC (charged had.)
proton target
Q2 = 2.5 GeV2/c2
• Reasonable agreement with results using S. Kretzter FF
• very weak xbj dependence
E.C. Aschenauer Pan Pacific, Tokyo, July 2005 30
K± - Multiplicity vs. z
10-2
10-1
1
0 0.1 0.2 0.3 0.4 0.5 0.6 0.7 0.8 0.9 1z
mu
ltip
licit
y
HERMES Preliminary
K+
excl. VM substractedexcl. VM included
proton target
Q2=2.5 GeV2/c2
10-3
10-2
10-1
0 0.1 0.2 0.3 0.4 0.5 0.6 0.7 0.8 0.9 1z
mu
ltip
licit
y
HERMES Preliminary
K-
excl. VM substractedexcl. VM included
proton target
Q2=2.5 GeV2/c2
• charge separated Kaon multiplicities
• Systematic uncertainty mainly from hadron PID correction
• low K− statistics =⇒ more statistics under way
E.C. Aschenauer Pan Pacific, Tokyo, July 2005 31
and Summary
• HERMES continues happily taking data with a transverse polarized p-target
Integrated DIS HERA Run II (polarized)
0
500
1000
1500
2000
2500
3000
x 10 3
0 50 100 150 200 250 300Day of Running
Nu
mb
er o
f p
ol.
DIS
eve
nts
2002/03
2003
2004
2005
• Transversity, Sivers and friends =⇒ G. Schnell• Exclusive reactions =⇒ Lq
DVCS: AUT =⇒ sensitive to GPD H + E =⇒ Ju =⇒ Y. Miyachiexclusive ρ0 / π+: AUT =⇒ sensitive to GPD E / H+ E =⇒ A. Rostomyan
• finalize most of HERA-I analysis
• gd1 ,gp
1 ,gn1 ,b1,∆q
• Extraction of FF very close• new Millennium extraction of ∆q (Purity free)• new ∆s + ∆s extraction using isoscalor method
• the nice description of HERMES data by Monte Carlo will allowa new extraction of ∆G/G
Many more results to come from physics topics not touched in this talk
E.C. Aschenauer Pan Pacific, Tokyo, July 2005 32
and Summary
• HERMES continues happily taking data with a transverse polarized p-targetIntegrated DIS HERA Run II (polarized)
0
500
1000
1500
2000
2500
3000
x 10 3
0 50 100 150 200 250 300Day of Running
Nu
mb
er o
f p
ol.
DIS
eve
nts
2002/03
2003
2004
2005
• Transversity, Sivers and friends =⇒ G. Schnell• Exclusive reactions =⇒ Lq
DVCS: AUT =⇒ sensitive to GPD H + E =⇒ Ju =⇒ Y. Miyachiexclusive ρ0 / π+: AUT =⇒ sensitive to GPD E / H+ E =⇒ A. Rostomyan
• finalize most of HERA-I analysis
• gd1 ,gp
1 ,gn1 ,b1,∆q
• Extraction of FF very close• new Millennium extraction of ∆q (Purity free)• new ∆s + ∆s extraction using isoscalor method
• the nice description of HERMES data by Monte Carlo will allowa new extraction of ∆G/G
Many more results to come from physics topics not touched in this talk
E.C. Aschenauer Pan Pacific, Tokyo, July 2005 32
and Summary
• HERMES continues happily taking data with a transverse polarized p-target
Integrated DIS HERA Run II (polarized)
0
500
1000
1500
2000
2500
3000
x 10 3
0 50 100 150 200 250 300Day of Running
Nu
mb
er o
f p
ol.
DIS
eve
nts
2002/03
2003
2004
2005
• Transversity, Sivers and friends =⇒ G. Schnell• Exclusive reactions =⇒ Lq
DVCS: AUT =⇒ sensitive to GPD H + E =⇒ Ju =⇒ Y. Miyachiexclusive ρ0 / π+: AUT =⇒ sensitive to GPD E / H+ E =⇒ A. Rostomyan
• finalize most of HERA-I analysis
• gd1 ,gp
1 ,gn1 ,b1,∆q
• Extraction of FF very close• new Millennium extraction of ∆q (Purity free)• new ∆s + ∆s extraction using isoscalor method
• the nice description of HERMES data by Monte Carlo will allowa new extraction of ∆G/G
Many more results to come from physics topics not touched in this talk
E.C. Aschenauer Pan Pacific, Tokyo, July 2005 32
and Summary
• HERMES continues happily taking data with a transverse polarized p-target
Integrated DIS HERA Run II (polarized)
0
500
1000
1500
2000
2500
3000
x 10 3
0 50 100 150 200 250 300Day of Running
Nu
mb
er o
f p
ol.
DIS
eve
nts
2002/03
2003
2004
2005
• Transversity, Sivers and friends =⇒ G. Schnell• Exclusive reactions =⇒ Lq
DVCS: AUT =⇒ sensitive to GPD H + E =⇒ Ju =⇒ Y. Miyachiexclusive ρ0 / π+: AUT =⇒ sensitive to GPD E / H+ E =⇒ A. Rostomyan
• finalize most of HERA-I analysis
• gd1 ,gp
1 ,gn1 ,b1,∆q
• Extraction of FF very close• new Millennium extraction of ∆q (Purity free)• new ∆s + ∆s extraction using isoscalor method
• the nice description of HERMES data by Monte Carlo will allowa new extraction of ∆G/G
Many more results to come from physics topics not touched in this talk
E.C. Aschenauer Pan Pacific, Tokyo, July 2005 32
and Summary
• HERMES continues happily taking data with a transverse polarized p-target
Integrated DIS HERA Run II (polarized)
0
500
1000
1500
2000
2500
3000
x 10 3
0 50 100 150 200 250 300Day of Running
Nu
mb
er o
f p
ol.
DIS
eve
nts
2002/03
2003
2004
2005
• Transversity, Sivers and friends =⇒ G. Schnell• Exclusive reactions =⇒ Lq
DVCS: AUT =⇒ sensitive to GPD H + E =⇒ Ju =⇒ Y. Miyachiexclusive ρ0 / π+: AUT =⇒ sensitive to GPD E / H+ E =⇒ A. Rostomyan
• finalize most of HERA-I analysis
• gd1 ,gp
1 ,gn1 ,b1,∆q
• Extraction of FF very close• new Millennium extraction of ∆q (Purity free)• new ∆s + ∆s extraction using isoscalor method
• the nice description of HERMES data by Monte Carlo will allowa new extraction of ∆G/G
Many more results to come from physics topics not touched in this talk
E.C. Aschenauer Pan Pacific, Tokyo, July 2005 32
and Summary
• HERMES continues happily taking data with a transverse polarized p-target
Integrated DIS HERA Run II (polarized)
0
500
1000
1500
2000
2500
3000
x 10 3
0 50 100 150 200 250 300Day of Running
Nu
mb
er o
f p
ol.
DIS
eve
nts
2002/03
2003
2004
2005
• Transversity, Sivers and friends =⇒ G. Schnell• Exclusive reactions =⇒ Lq
DVCS: AUT =⇒ sensitive to GPD H + E =⇒ Ju =⇒ Y. Miyachiexclusive ρ0 / π+: AUT =⇒ sensitive to GPD E / H+ E =⇒ A. Rostomyan
• finalize most of HERA-I analysis
• gd1 ,gp
1 ,gn1 ,b1,∆q
• Extraction of FF very close• new Millennium extraction of ∆q (Purity free)• new ∆s + ∆s extraction using isoscalor method
• the nice description of HERMES data by Monte Carlo will allowa new extraction of ∆G/G
Many more results to come from physics topics not touched in this talk
E.C. Aschenauer Pan Pacific, Tokyo, July 2005 32
and Summary
• HERMES continues happily taking data with a transverse polarized p-target
Integrated DIS HERA Run II (polarized)
0
500
1000
1500
2000
2500
3000
x 10 3
0 50 100 150 200 250 300Day of Running
Nu
mb
er o
f p
ol.
DIS
eve
nts
2002/03
2003
2004
2005
• Transversity, Sivers and friends =⇒ G. Schnell• Exclusive reactions =⇒ Lq
DVCS: AUT =⇒ sensitive to GPD H + E =⇒ Ju =⇒ Y. Miyachiexclusive ρ0 / π+: AUT =⇒ sensitive to GPD E / H+ E =⇒ A. Rostomyan
• finalize most of HERA-I analysis
• gd1 ,gp
1 ,gn1 ,b1,∆q
• Extraction of FF very close• new Millennium extraction of ∆q (Purity free)• new ∆s + ∆s extraction using isoscalor method
• the nice description of HERMES data by Monte Carlo will allowa new extraction of ∆G/G
Many more results to come from physics topics not touched in this talk
E.C. Aschenauer Pan Pacific, Tokyo, July 2005 32