1. TMD experiments from COMPASS SIDIS
Firstly, I’d like to thank the organizers
for inviting me to give a talk.
The title of my talk is
“Experimental study with lepton scattering.”
I’ll review the recent progress
in the study of the nucleon structure
in lepton scattering experiments.
Takahiro Iwata,
(Yamagata University)
on behalf of COMPASS Collaboration
Hadron China 2017, 24-28, 2017, Nanjing

2. OUTLINE Introduction COMPASS setup for DIS & SIDIS Nucleon PDFs
Collins asymmetry
Collins Asymmetry for single-hadron production
Di-hadron Asymmetry
Sivers asymmetry
Sivers Asymmetry for single-hadron production
Weighted Sivers asymmetry
Gluon Sivers asymmetry
Conclusion
This is the outline of my talk.
Following a brief introduction.
I’ll talk about these topics;
Longitudinal Spin Structure
Transverse Spin Effects
GPD Studies
Takahiro IWATA, Hadron China 2017, 24-28, 2017, Nanjing

3. COMPASS at CERN DIS & SI-DIS setup with muon & PT Polarised Target
Straws
SDC
MWPC
W45
SciFi
Silicon
Micromegas
GEMs
MuonWall
Polarised
Target
(NH3 for p,
6LiD for d)
COMPASS is the similar experiment,
which is currently running at CERN.
using high energy polarized muon beam
with the energy up to 200GeV
and the polarized solid target.
Thanks to the multi-purpose spectrometer,
SI-DIS events are also measured.
E/HCAL
E/HCAL
SM1
SM2
MuonWall
Pol.
beam
fom SPS
GeV,
pol. = 80%
RICH
two stage spectrometer
tracking, calorimetry, PID
Takahiro IWATA, Hadron China 2017, 24-28, 2017, Nanjing

4. The Polarized Target System
DNP technique with a dilution refrigerator
(Tmin.=30mK) , a 2.5T superconducting magnet and microwave (70GHz) system
2/3 target sections (60+60 cm/ cm)
longitudinal & transverse pol. modes
The world
biggest PT
beam
COMPASS is the similar experiment,
which is currently running at CERN.
using high energy polarized muon beam
with the energy up to 200GeV
and the polarized solid target.
Thanks to the multi-purpose spectrometer,
SI-DIS events are also measured.
NH3
6LiD
 Polarization of proton(NH3 ) ~90%
Polarization of deuteron( 6LiD) ~50%
6Li (~ a+d) also polarized
 dilution factor f=50%
Takahiro IWATA, Hadron China 2017, 24-28, 2017, Nanjing

5. The Polarized Target System
DNP technique with a dilution refrigerator
(Tmin.=30mK) , a 2.5T superconducting magnet and microwave (70GHz) system
2/3 target sections (60+60 cm/ cm)
longitudinal & transverse pol. modes
The world
biggest PT
beam
COMPASS is the similar experiment,
which is currently running at CERN.
using high energy polarized muon beam
with the energy up to 200GeV
and the polarized solid target.
Thanks to the multi-purpose spectrometer,
SI-DIS events are also measured.
NH3
6LiD
 Polarization of proton(NH3 ) ~90%
Polarization of deuteron( 6LiD) ~50%
6Li (~ a+d) also polarized
 dilution factor f=50%
Takahiro IWATA, Hadron China 2017, 24-28, 2017, Nanjing

6. Nucleon PDFs unpol. long. pol. trans. pol. unpol. long. pol. Quark
At LO, taking account of
transverse momentum(kT) of the quarks
Nucleon PDFs
Nucleon
unpol.
long. pol.
trans. pol.
number
density
Sivers
unpol.
Nucleon
Parton
T-odd
worm-gear-1
helicity
When you take account of the transverse momentum,
you need additional functions. Transverse Momentum Dependent PDF.,
One of them is Sivers function which may be the most famous one.
It attracts attention because it is related to OAM of quarks.
As well as the Sivers function, BM function is also interesting,
because it means correlation between transverse spin
and the transvers momentum of the quarks.
So, it is sensitive to LS coupling
and it is also related to OAM.
long. pol.
Quark
transversity
Boer-Mulders
trans. pol.
worm-gear-2
pretzelosity
T-odd
Takahiro IWATA, Hadron China 2017, 24-28, 2017, Nanjing

7. Sivers & BM-functions unpol. long. pol. trans. pol.
Nucleon
unpol.
long. pol.
trans. pol.
Sivers
Sivers- and BM-functions are
relateted to quark OAM and expected to be process dependent
unpol.
T-odd
When you take account of the transverse momentum,
you need additional functions. Transverse Momentum Dependent PDF.,
One of them is Sivers function which may be the most famous one.
It attracts attention because it is related to OAM of quarks.
As well as the Sivers function, BM function is also interesting,
because it means correlation between transverse spin
and the transvers momentum of the quarks.
So, it is sensitive to LS coupling
and it is also related to OAM.
long. pol.
Quark
SIDIS DY
Boer-Mulders
trans. pol.
T-odd
Takahiro IWATA, Hadron China 2017, 24-28, 2017, Nanjing

8. SIDIS x-section for single hadron production
S: nucleon covariant spin vector
l:lepton helicity
Sivers
Here is the recent result
for the Collins Asymmetry
obtained for proton target,
for positive and negative pions.
What we can see here is
non-zero signal is clearly visible.
s: nucleon spin
(initial quark spin)
s’: struck quark spin
Collins
Transverse Target Spin Asymmetries
Scattering plane
quark direction
hadron
（Breit frame）
15 asymmetries:
2-”UU”,1-”LU”,2-”UL”, 2-”LL”,5-”UT”, 3-”LT”
All measured in COMPASS for p & d
Takahiro IWATA, Hadron China 2017, 24-28, 2017, Nanjing

9. Collins & Sivers asymmetries
Transversity
Collins F.F. (polarized quark fragmentation)
can be used for quark polarimeter
Collins mechanism
This is the outline of my talk.
Following a brief introduction.
I’ll talk about these topics;
Longitudinal Spin Structure
Transverse Spin Effects
GPD Studies
unpol. F.F.
Sivers PDF
Sivers effect
Takahiro IWATA, Hadron China 2017, 24-28, 2017, Nanjing

10. Collins Asymmetry on Proton
Event Selection
Q2>1 (GeV/c)2
W>5 GeV/c2
0.05 < y < 0.9
z > 0.1
|PhT| > 0.07 GeV/c
Collins Asymmetry on Proton p-
Clearly non-zero
in valence region,
negative for p+ ,
positive for p- - p+ K-
Similar trend for K,
negative for K+ ,
positive for K--
Here is the recent result
for the Collins Asymmetry
obtained for proton target,
for positive and negative pions.
What we can see here is
non-zero signal is clearly visible. K+
K0->p+p- K0
Deuteron target asymmetries compatible with zero (COMPASS PLB673 (2009) 127 )
PLB 744 (2015) 250
z=Eh/n
Takahiro IWATA, Hadron China 2017, 24-28, 2017, Nanjing

11. Collins Asymmetry compared with a Fit
Transversity u p+
The fit reproduces the COMPASS data well d p-
Here is the recent result
for the Collins Asymmetry
obtained for proton target,
for positive and negative pions.
What we can see here is
non-zero signal is clearly visible.
Collins F.F.
up+
favoured
up-
global fit by Anselmino group with HERMES, COMPASS, Belle data
[PRD87(2013) ]
dis-favoured
Takahiro IWATA, Hadron China 2017, 24-28, 2017, Nanjing

12. Di-hadron Asymmetry & Transversity
Transversity PDF
“Di-hadron FF”
Modulation according to
fR: azimuthal angle of
R (Relative hadron momentum vector)
Using the Collins asymmetries, global analysis has been carried out
along with data obtained by BELLE
to extract the transversity and the Collins FF.
This is obtained transversity, for u and d quark.
They give opposite signs to each other
and
their shapes are similar to
the helicity distributions
but the intensities are slightly smaller.
fS’: azimuthal angle of struck quark spin
fS: azimuthal angle of initial quark spin
Takahiro IWATA, Hadron China 2017, 24-28, 2017, Nanjing

13. Di-hadron Asymmetry on Proton
Event Selection
Q2>1 (GeV/c)2
W>5 GeV/c2
0.1 < y < 0.9
z > 0.1
|RT| > 0.07 GeV/c r0
pion mass is assumed
COMPASS 2007/2010 proton
Npair=3.5x107
after the cuts
Clearly negative
in the valence region
Using the Collins asymmetries, global analysis has been carried out
along with data obtained by BELLE
to extract the transversity and the Collins FF.
This is obtained transversity, for u and d quark.
They give opposite signs to each other
and
their shapes are similar to
the helicity distributions
but the intensities are slightly smaller.
Phys. Lett. B736 (2014) 124
Deuteron data also published
PLB　713 (2012) 10
The asymmetry is compatible with zero !
Takahiro IWATA, Hadron China 2017, 24-28, 2017, Nanjing

14. Interplay; Di-hadron & Collins Asymmetries
[1] Mirror symmetry
between Collins h+ and h-
[2] Di-hadron asymmetry
similar to the Collins h+
 Hint of common physical origin between Di-hadron FF
and Collins mechanism
Using the Collins asymmetries, global analysis has been carried out
along with data obtained by BELLE
to extract the transversity and the Collins FF.
This is obtained transversity, for u and d quark.
They give opposite signs to each other
and
their shapes are similar to
the helicity distributions
but the intensities are slightly smaller.
PLB 736 (2014) 124
Further study on the Collins asymmetries for the di-hadron events gave indication that they are driven by the common origin
COMPASS PLB 753 (2016) 406 x y h+ h- R S’
: positive
: negative
Takahiro IWATA, Hadron China 2017, 24-28, 2017, Nanjing

15. Sivers Asymmetry on Proton
Event Selection
Q2>1 (GeV/c)2
W>5 GeV/c2
0.05 < y < 0.9
z > 0.1
|PhT| > 0.07 GeV/c p+
Significantly large signal for p+ and K+ p- K+
Compatible with zero for p- , K - and K0
OK, next one is Sivers asymmetry.
This is the recent data
for positive and negative pion
for proton target.
As you can see,
they are clearly positive for positive pions.
While, for negative pions almost zero.
K0->p+p- K-
PLB 744 (2015) 250 K0
Deuteron target asymmetries compatible with zero
(COMPASS PLB673 (2009) 127 )
Takahiro IWATA, Hadron China 2017, 24-28, 2017, Nanjing

16. Sivers Asymmetry on Proton; p+ & K+
K+ signal is even larger
than that of p+
possible contribution
from sea quarks
OK, next one is Sivers asymmetry.
This is the recent data
for positive and negative pion
for proton target.
As you can see,
they are clearly positive for positive pions.
While, for negative pions almost zero. p+
Takahiro IWATA, Hadron China 2017, 24-28, 2017, Nanjing

17. Sivers Asymmetry compared with Global Fits
The fits reproduce the COMPASS data
reasonabley well. p+
Here is the recent result
for the Collins Asymmetry
obtained for proton target,
for positive and negative pions.
What we can see here is
non-zero signal is clearly visible. p-
COMPASS results for unidentified hadrons on proton is included
in the global fits
Takahiro IWATA, Hadron China 2017, 24-28, 2017, Nanjing

18. Extracted Sivers function by global fits
G.Miguel et al., Phys. Rev. D 89, (2014)
Here is the recent result
for the Collins Asymmetry
obtained for proton target,
for positive and negative pions.
What we can see here is
non-zero signal is clearly visible.
Anselmino et al., Eur.Phys.J.A39:89-100,2009
Takahiro IWATA, Hadron China 2017, 24-28, 2017, Nanjing

19. Q2 dependence of Sivers Asymmetries
COMPASS has measured the TSA in different Q2 ranges in SIDIS
SIDIS
Drell-Yan
high mass DY
Here is the recent result
for the Collins Asymmetry
obtained for proton target,
for positive and negative pions.
What we can see here is
non-zero signal is clearly visible.
Sivers
PBL 770 (2017)138
h+ : The data are positive in all the Q2-ranges.
h- : The lowest Q2 data are compatible with 0 and data become significantly positive in the other ranges.
Takahiro IWATA, Hadron China 2017, 24-28, 2017, Nanjing

20. Multi Dimensional Sivers Asymmetries
PBL 770 (2017)138
h+ : A>0 in whole Q2,
increasing as x, z & Pt.
h- : less and not prominent
Here is the recent result
for the Collins Asymmetry
obtained for proton target,
for positive and negative pions.
What we can see here is
non-zero signal is clearly visible.
Takahiro IWATA, Hadron China 2017, 24-28, 2017, Nanjing

21. Other TSAs in different Q2 ranges
transverse target spin Asymmetries
PLB 770 (2017) 138
Sivers
Collins
Here is the recent result
for the Collins Asymmetry
obtained for proton target,
for positive and negative pions.
What we can see here is
non-zero signal is clearly visible.
beam spin & target spin Asymmetries
Takahiro IWATA, Hadron China 2017, 24-28, 2017, Nanjing

22. PTh Weighted Sivers Asymmetry
“standard” Sivers Asymmetry:
LO QCD parton model
: convolution over transverse momenta
usually solved
using Gaussian model for PDF and FFs
Here is the recent result
for the Collins Asymmetry
obtained for proton target,
for positive and negative pions.
What we can see here is
non-zero signal is clearly visible.
g* N CM system
simple product
Model dependent !
Takahiro IWATA, Hadron China 2017, 24-28, 2017, Nanjing

23. PTh Weighted Sivers Asymmetry
If you weight with
proposed by
convolution  simple product of Sivers(first moment) and FF
Here is the recent result
for the Collins Asymmetry
obtained for proton target,
for positive and negative pions.
What we can see here is
non-zero signal is clearly visible.
first moment of Sivers PDF
model independent way ( no assumption on the shape of PDFs and FFs)
Takahiro IWATA, Hadron China 2017, 24-28, 2017, Nanjing

24. PTh Weighted Sivers Asymmetry
Here is the recent result
for the Collins Asymmetry
obtained for proton target,
for positive and negative pions.
What we can see here is
non-zero signal is clearly visible.
Takahiro IWATA, Hadron China 2017, 24-28, 2017, Nanjing

25. Gluon Sivers Asymmetry
Sivers effect for also gluons? Gluon OAM ?
Recent review  D. Boer et al., Adv. High Energy Phys., 2015, (2015).
It can be studied with the asymmetry for photon-gluon-fusion
To enhance the PGF, 2-hadrons with high Pt are detected.
hadron
Here is the recent result
for the Collins Asymmetry
obtained for proton target,
for positive and negative pions.
What we can see here is
non-zero signal is clearly visible.
The azimuthal angle of the hadron pair, f2h , is strongly correlated with the gluon azimuthal angle fg
Data sample : 2010 proton target, 2003,4 deuteron target
Event selection :
Without charge constraint for the hadron pair
Takahiro IWATA, Hadron China 2017, 24-28, 2017, Nanjing

26. Gluon Sivers Asymmetry
However, one has to take account of the background processes; + BG
signal
The asymmetry can be decomposed as: MC
Here is the recent result
for the Collins Asymmetry
obtained for proton target,
for positive and negative pions.
What we can see here is
non-zero signal is clearly visible.
With a help of MC simulation, the process fractions(Ri) are evaluated.
The MC simulation :
Generator LEPTO + GEANT + Reconstruction program
PDF: MSTW2008
Parton shower: on
FLUKA for secondary interactions
Special generator tuning for high-Pt events
Fitting the data with Neural Network trained by the MC, each asymmetry is determined.
Takahiro IWATA, Hadron China 2017, 24-28, 2017, Nanjing

27. Gluon Sivers Asymmetry : Results
Here is the recent result
for the Collins Asymmetry
obtained for proton target,
for positive and negative pions.
What we can see here is
non-zero signal is clearly visible.
proton & deuteron combined
Two standard deviation from zero  Gluon Sivers effect ?
Takahiro IWATA, Hadron China 2017, 24-28, 2017, Nanjing

28. Conclusions
SIDIS gave and is giving fundamental contribution to the study of the transverse spin structure of the nucleon.
COMPASS has provided TSA data for proton and deuteron.
The Collins asymmetries and Sivers Asymmetries were found to be different from zero for proton although they are consistent with zero for deuteron.
There is an interplay between the single hadron Collins asymmetries and di-hadron asymmetries suggesting common origin in production mechanism.
The Sivers asymmetries were obtained in different Q2 ranges. One of the ranges corresponds to the di-muon mass range where the Drell-Yan measurement of COMPASS was performed.
The Sivers asymmetry for PGF was found to be negative with two standard deviation from zero suggesting the possible gluon Sivers effect.
Now, let me conclude my talk.
Significant progress in the study　with lepton scattering was achieved
Du and Dd are well determined
Polarized sea distributions are small
Gluon polarization is compatible with 0 in the measured range
Transversity and Sivers PDF have been extracted
The asymmetry on un-polarized nucleon gives a hint of BM PDF
Wealth of GPD data were accumulated by HERMES and Jlab-experiments
Exciting GPD programs at COMPASS-II and JLab-12GeV are planned
Takahiro IWATA, Hadron China 2017, 24-28, 2017, Nanjing

29. Spares Firstly, I’d like to thank the organizers
for inviting me to give a talk.
The title of my talk is
“Experimental study with lepton scattering.”
I’ll review the recent progress
in the study of the nucleon structure
in lepton scattering experiments.
Hadron China 2017, 24-28, 2017, Nanjing

30. Comparison with calculations
In good agreement
with the calculations
in low-z & low Pt ranges.
Calculations are based on fits of one-dimensional data
( PRD72(2005) [Erratum:PRD (2005)], EPJ A39 (2009)89)
Here is the recent result
for the Collins Asymmetry
obtained for proton target,
for positive and negative pions.
What we can see here is
non-zero signal is clearly visible.
PBL 770 (2017)138
However,
in high-z & high-Pt ranges,
clear discrepancies are seen.
PBL 770 (2017)138
Takahiro IWATA, Hadron China 2017, 24-28, 2017, Nanjing

31. Expected property for the Sivers PDF
Sivers function is process dependent.
sign change !
SIDIS : with final state interaction (FSI)
Drell-Yan: with initial state interaction (ISI)
In this study,
angular modulations in SIDIS are important.
The x-section for the transversely polarized nucleon target
is expected to give modulations
according to the hadron angle, as shown here.
This part gives Collins asymmetry which contains information on the Transversity
and　this part Sivers asymmetry giving Sivers function
repulsive
attractive
ejected (red) quark is attracted by the anti-red spectators
before annihilating with the red active quark, the approaching anti-quark(anti-red) is repelled by the anti-red spectators
This is to be checked in the common kinematical region in COMPASS experimentally.
Takahiro IWATA, Hadron China 2017, 24-28, 2017, Nanjing

32. SIDIS Kinematics In this study,
angular modulations in SIDIS are important.
The x-section for the transversely polarized nucleon target
is expected to give modulations
according to the hadron angle, as shown here.
This part gives Collins asymmetry which contains information on the Transversity
and　this part Sivers asymmetry giving Sivers function
Fragmentation Function
Energy fraction of the hadron
Takahiro IWATA, Hadron China 2017, 24-28, 2017, Nanjing

33. Gluon Sivers Asymmetry : Results
Asymmetries for PGF
Here is the recent result
for the Collins Asymmetry
obtained for proton target,
for positive and negative pions.
What we can see here is
non-zero signal is clearly visible.
Asymmetries for BG
Takahiro IWATA, Hadron China 2017, 24-28, 2017, Nanjing