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MCEG for TMD physics: the quest tocharacterize perturbative and non perturbativeQCD phenomena(On behalf of Jefferson Lab TMD LDRD)
Nobuo SatoUniversity of Connecticut25th International Workshop on Deep Inelastic Scattering,Apr 6 2017
MotivationsMain objectives:
- Urgent requirement: MCEG for TMD physics- Language dictionary between in NP and HEP- Improve the theoretical framework for TMDs
Why?- MCEG is a useful theory tool to describe exclusive final
states- Is a numerical implementation of QCD evolution and
nonperturbative physics- Needed for high-presicion nonperturbative physics
What do we need?- Put a bunch of physicists in a room- Use Pythia8+DIRE as a starting point- Use QCD factorization theorems as a guidance
2 / 18
MotivationsMain objectives:
- Urgent requirement: MCEG for TMD physics- Language dictionary between in NP and HEP- Improve the theoretical framework for TMDs
Why?- MCEG is a useful theory tool to describe exclusive final
states- Is a numerical implementation of QCD evolution and
nonperturbative physics- Needed for high-presicion nonperturbative physics
What do we need?- Put a bunch of physicists in a room- Use Pythia8+DIRE as a starting point- Use QCD factorization theorems as a guidance
2 / 18
MotivationsMain objectives:
- Urgent requirement: MCEG for TMD physics- Language dictionary between in NP and HEP- Improve the theoretical framework for TMDs
Why?- MCEG is a useful theory tool to describe exclusive final
states- Is a numerical implementation of QCD evolution and
nonperturbative physics- Needed for high-presicion nonperturbative physics
What do we need?
- Put a bunch of physicists in a room- Use Pythia8+DIRE as a starting point- Use QCD factorization theorems as a guidance
2 / 18
MotivationsMain objectives:
- Urgent requirement: MCEG for TMD physics- Language dictionary between in NP and HEP- Improve the theoretical framework for TMDs
Why?- MCEG is a useful theory tool to describe exclusive final
states- Is a numerical implementation of QCD evolution and
nonperturbative physics- Needed for high-presicion nonperturbative physics
What do we need?- Put a bunch of physicists in a room
- Use Pythia8+DIRE as a starting point- Use QCD factorization theorems as a guidance
2 / 18
MotivationsMain objectives:
- Urgent requirement: MCEG for TMD physics- Language dictionary between in NP and HEP- Improve the theoretical framework for TMDs
Why?- MCEG is a useful theory tool to describe exclusive final
states- Is a numerical implementation of QCD evolution and
nonperturbative physics- Needed for high-presicion nonperturbative physics
What do we need?- Put a bunch of physicists in a room- Use Pythia8+DIRE as a starting point
- Use QCD factorization theorems as a guidance
2 / 18
MotivationsMain objectives:
- Urgent requirement: MCEG for TMD physics- Language dictionary between in NP and HEP- Improve the theoretical framework for TMDs
Why?- MCEG is a useful theory tool to describe exclusive final
states- Is a numerical implementation of QCD evolution and
nonperturbative physics- Needed for high-presicion nonperturbative physics
What do we need?- Put a bunch of physicists in a room- Use Pythia8+DIRE as a starting point- Use QCD factorization theorems as a guidance
2 / 18
3 / 18
+JakeEthier+EricMoffat+AndreaSignori
TheoristsExperimentalists
LDRD personnel
3DNucleonTomography,March16th2017
Joosten
Collins
Melnitchouk
JLab
RogersDiefenthaler
PrestelLönnblad
Sjöstrand
Pythia
Sato
co-PI co-PIPI
Other
Progress
Validation of Pythia8+DIRE against HERA data- Implementation of DIS in pythia8 via DIRE parton shower- Dedicated comparisons between HERMES tune in pythia6
with against Pythia8
Dedicated study of FFs in pythia (this talk)- FFs in pythia- Validation of DGLAP formalism against parton
shower+Lund string model- Pythia8+DIRE vs world e+e− data
Extensions of the CSS formalism- Inclusion of string effects in QCD factorization
4 / 18
Progress
Validation of Pythia8+DIRE against HERA data- Implementation of DIS in pythia8 via DIRE parton shower- Dedicated comparisons between HERMES tune in pythia6
with against Pythia8
Dedicated study of FFs in pythia (this talk)- FFs in pythia- Validation of DGLAP formalism against parton
shower+Lund string model- Pythia8+DIRE vs world e+e− data
Extensions of the CSS formalism- Inclusion of string effects in QCD factorization
4 / 18
Progress
Validation of Pythia8+DIRE against HERA data- Implementation of DIS in pythia8 via DIRE parton shower- Dedicated comparisons between HERMES tune in pythia6
with against Pythia8
Dedicated study of FFs in pythia (this talk)- FFs in pythia- Validation of DGLAP formalism against parton
shower+Lund string model- Pythia8+DIRE vs world e+e− data
Extensions of the CSS formalism- Inclusion of string effects in QCD factorization
4 / 18
Validation of Pythia8+DIRE against HERA data
5 / 18
Factorization in SIDIS
6 / 18
l
l′
q
P
k
pq
ps
⋃ ⋃⋃ ⋃ ⋃⋃
QCD event
Factorization theorem (current fragmentation):dσ/dφ = H ⊗ f ⊗DHadrons can also be produced in the mid rapidity region →see discussion by J. Collins arXiv:1610.09994String type effects are potentially important
Factorization in SIDIS
6 / 18
l
l′
q
P
k
pq
ps
⋃ ⋃⋃ ⋃ ⋃⋃
QCD event
l
l′
q
P
k
pq
ps
leading region
Factorization theorem (current fragmentation):dσ/dφ = H ⊗ f ⊗DHadrons can also be produced in the mid rapidity region →see discussion by J. Collins arXiv:1610.09994String type effects are potentially important
Factorization in SIDIS
6 / 18
l
l′
q
P
k
pq
ps
⋃ ⋃⋃ ⋃ ⋃⋃
QCD event
l
l′
q
P
k
pq
ps
leading region
l
l′
q
P
k
pq
ps
factorization
Factorization theorem (current fragmentation):dσ/dφ = H ⊗ f ⊗DHadrons can also be produced in the mid rapidity region →see discussion by J. Collins arXiv:1610.09994String type effects are potentially important
Factorization in SIDIS
6 / 18
l
l′
q
P
k
pq
ps
⋃ ⋃⋃ ⋃ ⋃⋃
QCD event
l
l′
q
P
k
pq
ps
leading region
l
l′
q
P
k
pq
ps
factorization
Factorization theorem (current fragmentation):dσ/dφ = H ⊗ f ⊗D
Hadrons can also be produced in the mid rapidity region →see discussion by J. Collins arXiv:1610.09994String type effects are potentially important
Factorization in SIDIS
6 / 18
l
l′
q
P
k
pq
ps
⋃ ⋃⋃ ⋃ ⋃⋃
QCD event
l
l′
q
P
k
pq
ps
leading region
l
l′
q
P
k
pq
ps
factorization
Factorization theorem (current fragmentation):dσ/dφ = H ⊗ f ⊗DHadrons can also be produced in the mid rapidity region →see discussion by J. Collins arXiv:1610.09994
String type effects are potentially important
Factorization in SIDIS
6 / 18
l
l′
q
P
k
pq
ps
⋃ ⋃⋃ ⋃ ⋃⋃
QCD event
l
l′
q
P
k
pq
ps
leading region
l
l′
q
P
k
pq
ps
factorization
Factorization theorem (current fragmentation):dσ/dφ = H ⊗ f ⊗DHadrons can also be produced in the mid rapidity region →see discussion by J. Collins arXiv:1610.09994String type effects are potentially important
String effects: PLB261 (1991) (OPAL Collaboration)
7 / 18
3 Jets events: QQ̄ and gluon jets. Jets are projected into a planeψ: angle of a given particle relative to the quark jet with the highestenergyψA: angle between highest energetic jet and gluon jetψC : angle between quark jetsOnly events with ψA = ψC are kept
Particle flow asymmetry is observed → evidence of string effects
String effects: PLB261 (1991) (OPAL Collaboration)
7 / 18
3 Jets events: QQ̄ and gluon jets. Jets are projected into a planeψ: angle of a given particle relative to the quark jet with the highestenergyψA: angle between highest energetic jet and gluon jetψC : angle between quark jetsOnly events with ψA = ψC are keptParticle flow asymmetry is observed → evidence of string effects
Study of FFs inpythia8+DIRE
8 / 18
Technical details
9 / 18
Simulate e+e− at Q = 30, 91.2, 1000 GeV flavor by flavor
Fit π and K FFs using pQCD @ NLO
1σTOT
dσh±q
dz(z,Q2) = 2
σTOT
[Cq ⊗Dq+(z,Q2) + Cg ⊗Dg(z,Q2)
]
ZMVS with input Q0 = 11GeV
Parametrization: Dq+(z) = Nzα(1− z)β(1 + c1z + c2z2 + ...)
Technical details
9 / 18
Simulate e+e− at Q = 30, 91.2, 1000 GeV flavor by flavor
Fit π and K FFs using pQCD @ NLO
1σTOT
dσh±q
dz(z,Q2) = 2
σTOT
[Cq ⊗Dq+(z,Q2) + Cg ⊗Dg(z,Q2)
]
ZMVS with input Q0 = 11GeV
Parametrization: Dq+(z) = Nzα(1− z)β(1 + c1z + c2z2 + ...)
Technical details
9 / 18
Simulate e+e− at Q = 30, 91.2, 1000 GeV flavor by flavor
Fit π and K FFs using pQCD @ NLO
1σTOT
dσh±q
dz(z,Q2) = 2
σTOT
[Cq ⊗Dq+(z,Q2) + Cg ⊗Dg(z,Q2)
]
ZMVS with input Q0 = 11GeV
Parametrization: Dq+(z) = Nzα(1− z)β(1 + c1z + c2z2 + ...)
Technical details
9 / 18
Simulate e+e− at Q = 30, 91.2, 1000 GeV flavor by flavor
Fit π and K FFs using pQCD @ NLO
1σTOT
dσh±q
dz(z,Q2) = 2
σTOT
[Cq ⊗Dq+(z,Q2) + Cg ⊗Dg(z,Q2)
]
ZMVS with input Q0 = 11GeV
Parametrization: Dq+(z) = Nzα(1− z)β(1 + c1z + c2z2 + ...)
Pythia8 vs. collinear factorization (preliminary)
10 / 18
10−2
100
(1/σ
TO
T)dσ/dz d+
Q = 11GeV
u+ s+ c+ b+
10−2
100
(1/σ
TO
T)dσ/dz
Q = 30GeV
π+
K+Fit to π+
Fit to K+
10−2
100
(1/σ
TO
T)dσ/dz
Q = 91.2GeV
0.2 0.4 0.6 0.8 z
10−2
100
(1/σ
TO
T)dσ/dz
Q = 1000GeV0.2 0.4 0.6 0.8 z 0.2 0.4 0.6 0.8 z 0.2 0.4 0.6 0.8 z 0.2 0.4 0.6 0.8 z
Pythia8 vs. collinear factorization (preliminary)
11 / 18
−1.0
−0.5
0.0
0.5
1.0
(dat
a−
thy)/t
hy d+
Q = 11GeV
u+ s+ c+ b+
−1.0
−0.5
0.0
0.5
1.0
(dat
a−
thy)/t
hy
Q = 30GeV
−1.0
−0.5
0.0
0.5
1.0
(dat
a−
thy)/t
hy
Q = 91.2GeV
0.2 0.4 0.6 0.8 z−1.0
−0.5
0.0
0.5
1.0
(dat
a−
thy)/t
hy
Q = 1000GeV0.2 0.4 0.6 0.8 z 0.2 0.4 0.6 0.8 z 0.2 0.4 0.6 0.8 z 0.2 0.4 0.6 0.8 z
Pythia8+DIRE FFs (preliminary)
12 / 18
0.2 0.4 0.6 0.80.0
0.2
0.4
0.6
0.8
1.0
1.2
1.4
zDh q(z
)
d+
π+
K+
0.2 0.4 0.6 0.8
u+
0.2 0.4 0.6 0.8
s+
0.2 0.4 0.6 0.8 z0.0
0.2
0.4
0.6
0.8
1.0
1.2
1.4
zDh q(z
)
c+
0.2 0.4 0.6 0.8 z
b+
0.2 0.4 0.6 0.8 z
g
Q = 11 GeV
Q = 30 GeV
Q = 91.2 GeV
Q = 103 GeV
Pythia8+DIRE FFs (preliminary)
13 / 18
0.2 0.4 0.6 0.8
10−6
10−4
10−2
100
zDh q(z
)
d+π+
K+
0.2 0.4 0.6 0.8
u+
0.2 0.4 0.6 0.8
s+
0.2 0.4 0.6 0.8 z
10−6
10−4
10−2
100
zDh q(z
)
c+
0.2 0.4 0.6 0.8 z
b+
Q = 11 GeV
Q = 30 GeV
Q = 91.2 GeV
Q = 103 GeV
0.2 0.4 0.6 0.8 z
g
Pythia8+DIRE π FFs and other global analyses
14 / 18
0.2 0.4 0.6 0.810−5
10−4
10−3
10−2
10−1
100
101
zDh q(z
)
d+
π+
0.2 0.4 0.6 0.8
u+
0.2 0.4 0.6 0.8
s+
0.2 0.4 0.6 0.8 z10−5
10−4
10−3
10−2
10−1
100
101
zDh q(z
)
c+
0.2 0.4 0.6 0.8 z
b+
0.2 0.4 0.6 0.8 z
g
Pythia8
JAM
DSS
HKNS
AKK
Pythia8+DIRE K FFs and other global analyses
15 / 18
0.2 0.4 0.6 0.810−5
10−4
10−3
10−2
10−1
100
101
zDh q(z
)
d+
K
0.2 0.4 0.6 0.8
u+
0.2 0.4 0.6 0.8
s+
0.2 0.4 0.6 0.8 z10−5
10−4
10−3
10−2
10−1
100
101
zDh q(z
)
c+
0.2 0.4 0.6 0.8 z
b+
0.2 0.4 0.6 0.8 z
g
Pythia8
JAM
DSS
HKNS
AKK
Pythia8+DIRE vs global e+e− → π +X
16 / 18
10−3
10−1
1011
σTOT
dσdp
ARGUS π
1σTOT
dσdz
Belle
1σTOT
dσdp
BaBar
1σTOT
dσdxp
TASSO
10−3
10−1
1011
σTOT
dσdxp
TPC
β−1
σTOT
dσdz
TPC(uds)
β−1
σTOT
dσdz
TPC(c)
β−1
σTOT
dσdz
TPC(b)
10−3
10−1
101 sβdσdz
HRS
1σTOT
dσdx
TOPAZ
1σTOT
dσdp
OPAL
η
OPAL(u)
10−3
10−1
101 η
OPAL(d)
η
OPAL(s)
η
OPAL(c)
η
OPAL(b)
10−3
10−1
1011
σTOT
dσdxp
ALEPH
1σTOT
dσdxp
DELPHI
1σTOT
dσdxp
DELPHI(uds)
1σTOT
dσdxp
DELPHI(b)
0.2 0.4 0.6 0.8 z10−3
10−1
1011
σTOT
dσdxp
SLD
0.2 0.4 0.6 0.8 z
1σTOT
dσdxp
SLD(uds)
0.2 0.4 0.6 0.8 z
1σTOT
dσdxp
SLD(c)
0.2 0.4 0.6 0.8 z
1σTOT
dσdxp
SLD(b)
Pythia8+DIRE vs global e+e− → K +X
17 / 18
10−3
10−1
1011
σTOT
dσdp
ARGUS K
1σTOT
dσdz
Belle
1σTOT
dσdp
BaBar
1σTOT
dσdxp
TASSO
10−3
10−1
1011
σTOT
dσdxp
TPC
1σTOT
dσdx
TOPAZ
1σTOT
dσdp
OPAL
η
OPAL(u)
10−3
10−1
101 η
OPAL(d)
η
OPAL(s)
η
OPAL(c)
η
OPAL(b)
10−3
10−1
1011
σTOT
dσdxp
ALEPH
1σTOT
dσdxp
DELPHI
1σTOT
dσdxp
DELPHI(uds)
1σTOT
dσdxp
DELPHI(b)
0.2 0.4 0.6 0.8 z10−3
10−1
1011
σTOT
dσdxp
SLD
0.2 0.4 0.6 0.8 z
1σTOT
dσdxp
SLD(uds)
0.2 0.4 0.6 0.8 z
1σTOT
dσdxp
SLD(c)
0.2 0.4 0.6 0.8 z
1σTOT
dσdxp
SLD(b)
Summary of FF studies
18 / 18
So far...DGLAP formalism seems to work in Pythia8+DIRE from Q > 30GeVDifficulties in describing Pythia8’s sample at Q = 11GeVExtracted FFs are comparable with existing global QCD analysesPythia8+DIRE seems to describe world e+e− data. A new tune withDIRE is needed achive better agreement
Further questions
Test the role of quark and hadron massesExtract FFs from Pythia8’s SIDIS at low energiesDoes collinear factorization work in the combined SIDIS+e+e− ?Can we see the role of string effects?
3D tomography
Extended the analysis to TMD FFsExtract the nonperturbative components of CSS from Pythia8
Ongoing studies of SIDIS and MCEG-theory mismatches
Summary of FF studies
18 / 18
So far...DGLAP formalism seems to work in Pythia8+DIRE from Q > 30GeVDifficulties in describing Pythia8’s sample at Q = 11GeVExtracted FFs are comparable with existing global QCD analysesPythia8+DIRE seems to describe world e+e− data. A new tune withDIRE is needed achive better agreement
Further questionsTest the role of quark and hadron massesExtract FFs from Pythia8’s SIDIS at low energiesDoes collinear factorization work in the combined SIDIS+e+e− ?Can we see the role of string effects?
3D tomography
Extended the analysis to TMD FFsExtract the nonperturbative components of CSS from Pythia8
Ongoing studies of SIDIS and MCEG-theory mismatches
Summary of FF studies
18 / 18
So far...DGLAP formalism seems to work in Pythia8+DIRE from Q > 30GeVDifficulties in describing Pythia8’s sample at Q = 11GeVExtracted FFs are comparable with existing global QCD analysesPythia8+DIRE seems to describe world e+e− data. A new tune withDIRE is needed achive better agreement
Further questionsTest the role of quark and hadron massesExtract FFs from Pythia8’s SIDIS at low energiesDoes collinear factorization work in the combined SIDIS+e+e− ?Can we see the role of string effects?
3D tomographyExtended the analysis to TMD FFsExtract the nonperturbative components of CSS from Pythia8
Ongoing studies of SIDIS and MCEG-theory mismatches
Summary of FF studies
18 / 18
So far...DGLAP formalism seems to work in Pythia8+DIRE from Q > 30GeVDifficulties in describing Pythia8’s sample at Q = 11GeVExtracted FFs are comparable with existing global QCD analysesPythia8+DIRE seems to describe world e+e− data. A new tune withDIRE is needed achive better agreement
Further questionsTest the role of quark and hadron massesExtract FFs from Pythia8’s SIDIS at low energiesDoes collinear factorization work in the combined SIDIS+e+e− ?Can we see the role of string effects?
3D tomographyExtended the analysis to TMD FFsExtract the nonperturbative components of CSS from Pythia8
Ongoing studies of SIDIS and MCEG-theory mismatches
