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TMD Studies: Present and Future at JLab Workshop Pavia, Dec. 19-20, 2018

Explore TMDs at JLab through evolution studies, high-twist TMDs, dihadron production, and systematics. Learn about SIDIS, non-perturbative distributions, and JLab12 proposals.

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TMD Studies: Present and Future at JLab Workshop Pavia, Dec. 19-20, 2018

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  1. SIDIS studies at JLab12 Harut Avakian (JLab) Workshop TMDs at Jlab: present and future Pavia, 19-20 December Pavia, 19 Dec 2018

  2. Outline • Introduction • JLab12 proposals, coverage and observables • Studies of Q2-dependence & multidimensional binning • Evolution studies and higher twist TMDs • Transverse momentum and phase space • Dihadron production and exclusive limit • Understanding of systematics of measurements and the role of MC • Conclusions TMD means Transverse Momentum Dependent PDF with most important dependences making it different from other PDFs its dependence on transverse momentum and Q2(evolution)!!!

  3. Single hadron production in hard scattering xF>0 (current fragmentation) h xF<0 (target fragmentation) xF- momentum in the CM frame Target fragmentation Current fragmentation h h h h M PDF PDF GPD 1 -1 0 xF Fracture Functions kT-dependent PDFs Generalized PDFs Wide kinematic coverage of large acceptance detectors allowing studies of hadronization in the full kinematics (target and current fragmentation regions) is important for systematics

  4. SIDIS kinematical plane and observables y COMPASS JLEIC 4x60 HERMES x JLab12 EIC@HIAF z JLab12 z EIC corrections for the region of large kT~Q target polarization beam polarization Pavia, 19 Dec 2018

  5. JLEIC energy reach and luminosity 1035 LHC magnets energy range: Ee: 3 to 12 GeV Ep: 40 to 100 GeV √s: 20 to 65 GeV (upper limit depends on magnet tech. choice) Luminosity (cm-2s-1) 1034 • Electron complex • CEBAF • Electron collider ring • Ion complex • Ion source • SRF linac • Booster • Ion collider ring 1033 Main focus proton? Pavia, 19 Dec 2018

  6. Non-perturbative distributions Non-perturbative sea in nucleon is a key to understand the nucleon structure -- Large flavor asymmetry as evidence provides a hint for region where non-perturbative effects will be significant • Predictions from dynamical model of chiral symmetry breaking [Schweitzer, Strikman, Weiss JHEP 1301 (2013) 163]    -- kT (sea) >> kT (valence)    -- short-range correlations between partons (small-size q-qbar pairs)    -- directly observable in PT-dependence of hadrons in SIDIS “Pion tornado”? L • spin and momentum of struck quarks are correlated with remnant • correlations of spins of q-q-bar with valence quark spin and transverse momentum will lead to observable effects • Non-perturbative sea most relevant for x>0.01, more for 0.1<x<0.2 Pavia, 19 Dec 2018

  7. p SIDIS at JLab12 Complementary measurements with different targets SOLID CLAS12 E12-09-018 Combination of high resolution measurements from spectrometers combined with large acceptance data from CLAS12 and SOLID would allow to study TMDs in details in the valence region Pavia, 19 Dec 2018

  8. JLab12 proposals: Hall-C E12-13-007(R. Ent et al): Measurement of Semi-Inclusive p0 Production as Validation of Factorization requests: 25 PAC days to provide a critical foundation to validate the entire SIDIS program in studying the partonic structure of the nucleon PT = 0.2, 0.4, and 0.6 GeV a:(x, Q2) = (0.20, 2.00) b:(x, Q2) = (0.36, 3.00) c:(x, Q2) = (0.36, 4.00) d:(x, Q2)= (0.36, 5.50) e:(x, Q2) = (0.50, 4.80) f: (x, Q2) = (0.60, 6.00) What means “factorization checking”? Pavia, 19 Dec 2018

  9. JLab12 proposals: Hall-C E12-09-017(R. Ent et al): Transverse Momentum Dependence of Semi-Inclusive Pion Production z = 0.40 requests: 32 PAC days with LH2 and LD2 at 8.8 and 11 GeV to study of the kt widths of up and down quarks under the main assumption that the fragmentation functions do not depend on quark flavor PT = 0.2, 0.4, and 0.6 GeV x;Q2(GeV2) (0.20,2.00) (0.30,3.00) (0.40,4.00) (0.50,5.00) (0.30,1.80) (0.30,4.50) Cahn term on, no higher twist terms Pavia, 19 Dec 2018

  10. JLab12 proposals: Hall-C E12-06-104(R. Ent et al): Measurement of the Ratio R = L=T in Semi-Inclusive Deep-Inelastic Scattering requests: 40 PAC days with LH2 and LD2 at 6.6, 8.8 and 11 GeV to perform measurements of the ratio R = sL/sTof longitudinal to transverse cross sections in pion electroproduction. Pavia, 19 Dec 2018

  11. JLab12 proposals E12-09-018(B. Wojtsekhowski et al): Measurement of the Semi-Inclusive pi and kappa electro-production in DIS regime from transverselypolarized 3He target with the SBS&BB spectrometers in Hall A requests: performing measurements at two energies, 8.8 and 11 GeV, at two values of Q2 for each bin in x and z. Pavia, 19 Dec 2018

  12. JLab12 proposals E12-09-14 (H.Gao et al): Traget Single Spin Asymmetry in DIS with Polarized 3He at 11 GeV requests: 60 days 15mA on pol. 40cm 3He with SoLID. Pavia, 19 Dec 2018

  13. JLab12 proposals E12-10-006(H.Gao et al): Target Single Spin Asymmetry in Semi-Inclusive Deep-Inelastic (e, eπ+/-) Reaction on a Transversely Polarized 3He Target at 8.8 and 11 GeV requests: 90 days of 15mA on pol. 40cm 3He with SoLID. Pavia, 19 Dec 2018

  14. JLab12 proposals E12-06-112(Avakian et al): Probing the Proton’s Quark Dynamics in Semi-Inclusive Pion Production at 12 GeV requests: 2000 hours for 11 GeV on an unpolarized proton target, to probe the Collins fragmentation function and provide information on the leading-twist Boer-Mulders TMD, and allow the extraction of the transverse momentum, PT and Q2-dependence of the beam SSAs Pavia, 19 Dec 2018

  15. JLab12 proposals PR-12-11-109(Avakian et al): Studies of DihadronElectroproduction in DIS with Unpolarized and Longitudinally Polarized Hydrogen and Deuterium Targets E12-06-112B/E12-09-008B (S. Pisano) :Higher-twist collinear structure of the nucleon through di-hadron SIDIS on unpolarized hydrogen and deuterium requests: 56 days of running on unpolarized hydrogen and deuterium Pavia, 19 Dec 2018

  16. JLab12 proposals E12-07-107(Avakian et al): Studies of Spin-Orbit Correlations with Longitudinally Polarized Target requests: 30 days of running on NH3 and 50 days of running on ND3 (or possibly 6LiD or HD) to study flavor and polarization dependence of transverse momentum dependence of helicity distributions of quarks, measuring PT dependence of the double spin asymmetry x, z, PT and Q2 dependences of the sin to sin 2moments will be studied to probe the underlying T-odd distribution and fragmentation functions as well as verify the hypothesis that the former is twist-3, and the later twist-2. Pavia, 19 Dec 2018

  17. JLab12 proposals E12-09-007(Hafidi et al): Studies of partonic distributions using semi-inclusive production of Kaons requests: 56 days: unpolarized 80 days polarized measurements. for beam energy 11 GeV with proton and deuterium target. Pavia, 19 Dec 2018

  18. JLab12 proposals E12-09-008(Contalbrigo et al): Studies of the Boer-Mulders Asymmetry in Kaon Electroproduction with Hydrogen and Deuterium Targets requests: 56 days of unpolarized proton and deuterium target at 11 GeV. Pavia, 19 Dec 2018

  19. JLab12 proposals E12-09-009(Avakian et al): Studies of Spin-Orbit Correlations in KaonElectroproduction in DIS with Longitudinally Polarized Hydrogen and Deuterium Targets requests: 30 days of running on NH3 and 50 days of running on ND3 (or possibly 6Li D or HD), at 11 GeV. deuteron proton Pavia, 19 Dec 2018

  20. JLab12 proposals E12-12-009(Avakian et al):Measurement of transversity with dihadron production in SIDIS with transversely polarized target proton Pavia, 19 Dec 2018

  21. JLab12 proposals E12-11-111(M. Contalbrigo et al): Transverse spin effects in SIDIS at 11 GeV with a transversely polarized target using the CLAS12 Detector requests: 100 days of beam at 11 GeV on HDIce. Collins amplitudes Pavia, 19 Dec 2018

  22. JLab12 proposals PR12-10-010 (Jiang et al-deffered): A Detailed Study of the Reaction Mechanism in Semi-Inclusive DIS with the CLAS12 Detector requests: 250 hours each for beam energies of 8.8 and 6.6 GeV on an unpolarized deuterium target. How critical are bins fro Q2-dependence studies of SIDIS? Pavia, 19 Dec 2018

  23. What we learned so far Pavia, 19 Dec 2018

  24. Azimuthal asymmetries in SIDIS Non-perturbative vs perturbative Cahn 1978 Georgi & Politzer, Mendez 1978 EMC (1987) • Large cosf modulations observed by EMC were reproduced in electroproduction of hadrons in SIDIS with unpolarized targets at COMPASS and HERMES • Effect is dominated by non-perturbative Cahn contribution H. Avakian, LNF-2018, Dec 17

  25. All moments are relevant SimonettaLiuti (UVA) CTEQ Fall Meeting, Nov 10 H. Avakian, DPWG, Nov 15

  26. Quark-gluon correlations: flavor dependence • roughly equal p+p0 SSA • p- SSA much smaller, consistent with 0 or<0 CLAS/HERMES arXiv:1709.10054 Higher Twist PDFs collins contribution • Significant longitudinal beam and target SSA measured at HERMES, JLab and COMPASS may be related to higher twist distribution functions • sinf modulations for p+p0 consistent with dominance of Sivers mechanism • Subleading asymmetries comparable with leading ones (1/Q terms should be accounted) Pavia, 19 Dec 2018

  27. First look at CLAS12 data CLAS Preliminary With only 2% of expected unpolarized target data, clas12 already provides a superior measurement Will require fine multidimensional binning to study Q2-dependence Pavia, 19 Dec 2018

  28. ALU structure ~ distribution functions fragmentation functions • universal quantities are the distribution and fragmentation functions, • kinematic factors should be factored out • binning should be defined using minimization of the errors in extraction Pavia, 19 Dec 2018

  29. Q2-dependence: Kinematic factors qe>10 Ep>1.2 --------------- 0.3<z<0.8 1.1<MX 2<W<4 0.05<y<0.8 Diehl Asymmetry tend to increase at large Q2? Pavia, 19 Dec 2018

  30. Q2-dependence: Kinematic factors f(y)= qe>8 Ep>1.2 --------------- 0.2<x<0.3 0.3<z<0.8 1.1<MX 2<W<4 0.05<y<0.8 Strong dependence of kinematical variables on Q2 Pavia, 19 Dec 2018

  31. Q2-dependence: Kinematic factors f(y)= qe>8 Ep>1.2 --------------- 0.2<x<0.3 0.3<z<0.8 1.1<MX 2<W<4 0.05<y<0.8 Structure Function tend to increase at large Q2? Pavia, 19 Dec 2018

  32. Q2-dependence: Kinematic factors qe>8 Ep>1.2 --------------- 0.2<x<0.3 0.3<z<0.8 1.1<MX 2<W<4 0.05<y<0.8 Strong variations of kinematical variables vs Q2 even for small bins in x,Q2 Pavia, 19 Dec 2018

  33. Q2-dependence: Kinematic factors qe>8 Ep>1.2 --------------- 0.2<x<0.3 5 bins in z ->0.3<z<0.8 1.1<MX 2<W<4 0.05<y<0.8 May need finer binning in all involved variables to study PT and Q2 dependences Pavia, 19 Dec 2018

  34. From JLab12 to EIC JLab@12GeV (25/50/75) • 0.1<xB<0.7:valence quarks EIC √s = 140, 50, 15 GeV • 10-4<xB<0.3:gluons and quarks, higher PT and Q2. CLAS12 (2018 Spring) vs MC • Understanding of quark-gluon correlations is crucial for precision studies of the structure of the nucleon. • At medium energies all experiments measure very significant HT contributions • Large HT effects may indicate the breakdown of the theory • Overlap of EIC and JLab12 in the valence region will be crucial for the TMD program Pavia, 19 Dec 2018

  35. Multiplicities of hadrons in SIDIS COMPASS:1709.07374 • Lower the beam energy, less phase space for high PT • PT-weighting may be hard to control • What is the origin of the tail? • Is there a problem with the perturbative part (Sato) or with high PT-part of TMD? Pavia, 19 Dec 2018

  36. kT-max effects on observables M. Boglione, S. Melis & A. Prokudin Phys. Rev. D 84, 034033 2011 BM Cahn dashed line: full integration solid: within kinematical limits in WW approximation BM contribution seem to be less sensitive to phase space limitations p- p+ multiplicities are also sensitive to kinematic limitations (phase space) Pavia, 19 Dec 2018

  37. COMPASS Kaons arXiv:1802.00584 no significant Q2-dependence • multiplicity has strong dependence on the missing mass of the e’KX • within the perturbative quantum chromodynamics formalism an additional correction may be required, which takes into account the phase space available for hadronization. Pavia, 19 Dec 2018

  38. Di-hadron production in SIDIS 2h production in SIDIS provides access to correlations inaccessible in simple SIDIS (dihadron fragmentation, correlations of target and current regions, entanglement....) Beam SSA provides access to quark helicity in SIDIS via dihadron correlations using the helicity-dependent dihadron fragmentation function (DiFF) . Dedicated CLAS12 proposals: E12-06-112B/E12-09-008B H. Avakian, LNF-2018, Dec 17

  39. p+p- Vector meson contributions vsdihadrons Should we worry about pions/kaons coming from vector meson decays? What about r+ and r- What do we know about relevant observables for pions specifically coming from vector meson decays What about SIDIS rhos (can we measure?) What is radiative correction due to rho? Vector meson as resonance in dihadron production? COMPASS:1709.07374 p+p0 Pavia, 19 Dec 2018

  40. Generators for MC simulations • Full event generators (PYTHIA, PEPSI, LEPTO) • Dedicated event generators for e’hhx (TMDGen T.Hayward) Types of event generators: • Providing events with cross section • pros: easier defined systematics, can be directly compared with data • cons: require huge statistics to provide acceptance functions for kinematic edges with reasonable error bars. • Phase space with realistic x-sections provided as weight factors. • pros: acceptance for all acceptable kinematics can be provided with small error bars, much faster, easy to incorporate different models • cons: more efforts to define systematics, need weighting H. Avakian, LNF-2018, Dec 17

  41. Kinematical distributions: Data vs MC Run 3985 • Kinemtical distributions for di-hadron production well described in the SIDIS MC H. Avakian, LNF-2018, Dec 17

  42. Extracting beam SSA: cross check Input asymmetry Generated curves in reasonable agreement with extraction Small systematic difference (likely from acceptance) under investigation H. Avakian, LNF-2018, Dec 17

  43. JLab12 proposals Asaturyan et al, Phys.Rev. C85 (2012) 015202 What means “factorization checking”? Pavia, 19 Dec 2018

  44. Choosing binning (x vs Q2) SFs defined for practically a full grid Fixed beam energy limits the coverage Detector acceptance limits further the coverage Pavia, 19 Dec 2018

  45. Choosing binning (z vs PT) Could SFs be extracted from limited phase space, and what will be the systematics Pavia, 19 Dec 2018

  46. 3D PDF Extraction and VAlidation (EVA) framework EVA meetings at JLab to finalize goals and coordinate efforts SIDIS,DY,e+/e-) experiments Hard Scattering MC (GEANT, FASTMC,…) QCD fundamentals Library for Structure Function (SF) calculations 3D PDF and FF (models, parametrizations) event selection e’hX, e’hhX,.. Grid operations Radiative x-section x-section calculations SF calculations Data Counts (x-sections, multiplicities,….) Defined set of assumptions Defined set of assumptions Extract 3D PDFs extract x-section Extract SFs Validation of extracted SFs or 3D PDFs (for a given set of assumptions) Development of a reliable techniques for the extraction of 3D PDFs and fragmentation functions from the multidimensional experimental observables with controlled systematics requires close collaboration of experiment, theory and computing Pavia, 19 Dec 2018

  47. MC Generator to simulate SIDIS output SIDIS MC in 7D (10D) Theory p┴ Provide a set of SFl step-1 For a given model/theory based on underlying non-perturbative input and assumptions calculate SFl step-2 (for a given Ebeam,l,L) step-3 (detected for a given Detector configuration) Need criteria to compare the input and output parameter spaces (validate) Pavia, 19 Dec 2018

  48. Studies of 1D PDFs F. Aaron et al., JHEP 1001 (2010) P. Jimenez-Delgado et al (2014), 1403.3355. JAM (standard) inspired by the OAM Avakian et al • Strong model and parametrization dependence observed already for 1D PDFs • Different assumptions (positivity requirement,…) may change significantly the PDF (need self consistent fits of polarized and unpolarized target data!!!) Pavia, 19 Dec 2018

  49. Simple example • Generate SIDIS events with latest and greatest SFs with evolution for a given beam energy: • Put particles in GEANT MC for a specific detector (CLAS12/SOLID/…) • Extract observables of interest (SSA, multiplicity, x-sections,..) Use a given extraction framework with additional assumptions (gauss, with and without evolution,…) extract underlying SFs and 3D PDFs and see what you get H. Avakian, DPWG, Nov 15

  50. Fat tail distributions: Tsallis Boltzmann-Gibbs entropy q-Entropy or Tsallis (non-additive) entropy natural logarithm in the limit q 1. q-entropy requires the following constriction for energy Tsallis statistics has proved to be a viable tool for the description of systems with long-range forces Pavia, 19 Dec 2018

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