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
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
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 160-200 GeV, pol. = 80% RICH two stage spectrometer tracking, calorimetry, PID Takahiro IWATA, Hadron China 2017, 24-28, 2017, Nanjing
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/30+60+30 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 2002 - 2004 2006 - 2011 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
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/30+60+30 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 2002 - 2004 2006 - 2011 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
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
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
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
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
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
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. up+ favoured up- global fit by Anselmino group with HERMES, COMPASS, Belle data [PRD87(2013) 094019] dis-favoured Takahiro IWATA, Hadron China 2017, 24-28, 2017, Nanjing
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
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
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
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
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
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
Extracted Sivers function by global fits G.Miguel et al., Phys. Rev. D 89, 074013 (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
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
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
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
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
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
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
Gluon Sivers Asymmetry Sivers effect for also gluons? Gluon OAM ? Recent review D. Boer et al., Adv. High Energy Phys., 2015, 371396 (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
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
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
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
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
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)094007 [Erratum:PRD 72 099903(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
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
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
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