Impact of SoLID Experiment on TMDs

Transcription

1 Impact of SoLID Experiment on TMDs QCD Evolution Jefferson Lab, Newport News May th 2017 Tianbo Liu Duke University and Duke Kunshan University In collaboration with: N. Sato, A. Prokudin, W. Melnitchouk, Z. Ye, K. Allada, J.-P. Chen, H. Gao, Z.-B. Kang, P. Sun, F. Yuan, and the SoLID Collaboration

2 Nucleon Spin Decomposition Proton spin puzzle Spin decomposition ~ 0.3 Quark spin only contributes a small fraction to nucleon spin. J. Ashman et al., PLB 206, 364 (1988); NP B328, 1 (1989). Lattice QCD (kinetic decomposition) = JAM Collaboration, PR D 93, (2016). Access to Lq/g χqcd Collaboration, PR D 91, (2015). It is necessary to have transverse information. Coordinate space: GPDs Momentum space: TMDs 3D imaging of the nucleon. 2

3 5D Unified View of Nucleon Structure Light-front wave function Ψ (xi, kti) GTMD F(x, ΔT, kt) Generalized Transverse Momentum Dependent Wigner distribution ρ(x, bt, kt) ΔT = 0 d 2 kt d 2 kt 3D TMD f (x, kt) GPD H (x, ξ, t) ΙPD H (x, ξ, bt) d 2 kt t = 0 dx dx 1D PDF f (x) Form factor F (t) Charge density ρ (bt) dx t = 0 dbt Charge g 3

4 SIDIS differential cross section Structure Functions 18 structure functions F(x, z, Q 2, PT), model independent. (one photon exchange approximation) [Diehl&Sapeta EPJC2005] 4

5 SIDIS JLab-6GeV Hall A HRS L 16 o γ π Polarized 3 He Target e BigBite 30 o e First neutron data in SIDIS Electron beam energy: 5.9 GeV Average current: 12µA 40cm transversely polarized 3 He target Average polarization: 55.4 ± 2.8% electron arm scattered electron momentum 0.6~2.5 GeV/c hadron arm hadron momentum ~ 2.35 GeV/c Published results from E06-010: X. Qian et al., Sivers and Collins SSA of π ± production in SIDIS, Physical Review Letters 107, (2011). Y. Zhang et al., Pretzelosity SSA of π ± production in SIDIS, Physical Review C 90, (2014). Y.X. Zhao et al., Sivers and Collins SSA of K ± production in SIDIS, Physical Review C 90, (2014). J. Huang et al., Beam-target DSA of π ± production in SIDIS, Physical Review Letters 108, (2012). K. Allada et al., SSA of inclusive hadron, π ±, K ±, and proton, productions, Physical Review C 89, (R) (2014). Y.X. Zhao et al., DSA of inclusive hadron, π ±, K ±, and proton, productions, Physical Review C 92, (R) (2015). X. Yan et al., Unpolarized differential cross section of π ± production in SIDIS, Physical Review C 95, (2017). 5

6 SIDIS SSA/DSA Results from E X. Qian et al., PRL 107, (2011). Y. Zhang et al., PR C90, (2014). Y.X. Zhao et al., PR C90, (2014). J. Huang et al., PRL 108, (2012). 6

7 Differential Cross Section First measurement of unpolarized SIDIS differential cross section on 3 He target π + π X. Yan et al., Phys. Rev. C 95, (2017). 5 [x bins] 2 [PT bins] 10 [φφh bins] 7

8 Azimuthal Modulation cos φφh azimuthal modulations in unpolarized SIDIS cross section on 3 He target Fit with A (1 B cos φφh) to 10 φφh bins in each x, PT bin X. Yan et al., Phys. Rev. C 95, (2017). 8

9 Differential Cross Section First measurement of unpolarized SIDIS differential cross section on 3 He target π + π X. Yan et al., Phys. Rev. C 95, (2017). 10 [x bins] 10 [PT bins] 9

10 Multi-Hall SIDIS JLab 10

11 Overview of SoLID Solenoidal Large Intensity Device Full exploitation of JLab 12 GeV upgrade with broad physics Luminosity ~ cm -2 s -1 (open geometry) 3D nucleon structure TMD (Semi-inclusive DIS) GPD (TCS, DVMP, DVCS, DDVCS) Conformal anomaly J/ψ production near threshold Luminosity ~ cm -2 s -1 (baffled geometry) Standard model test, new physics in 10~20 TeV region Parity-violating DIS Five highly rated approved experiments Three SIDIS, one PVDIS, one J/ψ production Run group: di-hadron, TCS, inclusive SSA Strong collaboration 250+ collaborators from 70+ institutes, 13 countries Significant international collaborations and strong theoretical support 11 Target Collimator GEM Scint SoLID (SIDIS He3) EM Calorimeter (large angle) angl))) Coil and Yoke 1 m SoLID (PVDIS) Target Coil and Yoke 1 m Baffle GEM Light Gas Cherenkov Cherenkov Heavy Gas Cherenkov GEM Scint EM Calorimeter (forward angle) MRPC Beamline EM Calorimeter (forward angle) Beamline

12 Test new physics beyond SM SoLID SoLID + final Qweak E : Parity violating asymmetry in DIS with LH2 and LD2 targets. 6 GeV PVDIS [Nature2014] + other experiments Sub 1% precision over broad kinematic range High luminosity ~ cm -2 s -1 Large scattering angle large x and y Charge symmetry violation d/u ratio free of nuclear effect Precision test of SM with sensitivity to new PV physics in 10~20 TeV Search for charge symmetry violation at partonic level Test QCD higher twist corrections Measure d/u ratio for proton free of nuclear effect 12

13 Approved J/ψ near threshold production E : measure J/ψ near threshold production cross section on proton (LH2). SoLID Run group: E A Timelike Compton Scattering (TCS). Imaginary part: total cross section through the optical theorem. Real part: contains the conformal anomaly. Proton mass: Quark Energy 33 Quark Mass 11 threshold at 8.2 GeV and µ = 2 GeV Trace Anomaly 22 Gluon Energy 34 H. Gao et al., The Universe 3, no.2, 18 (2015). 13 electro- and photo- production with unprecedented precision in unexplored region Probe color force inside the nucleon Conformal anomaly (proton mass budget) A window for future J/ψ-N interaction studies

14 SoLID Approved SIDIS experiments 11/8.8 GeV E : Single Spin Asymmetry on Transversely polarized 3 He, 90 days. E : Single and Double Spin Asymmetry on Longitudinally polarized 3 He, 35 days. E : Single Spin Asymmetry on Transversely polarized proton (NH3), 120 days. Two run groups: E A, E A Dihadron process Target single spin asymmetry Ay High statistics (example) Projected data of E

15 SoLID Electron beam: 11GeV and 8.8 GeV Targets: neutron ( 3 He) and proton (NH3) Luminosity: ~ n cm -2 s -1, p cm -2 s -1 Azimuthal angle: full 2π coverage In beam polarization: ~60% ( 3 He), ~70% (NH3) 4D bins with high precision neutron ( 3 He) Q 2 (GeV 2 ) 10 COMPASS HERMES SoLID proton SoLID neutron W 2 cut =5.5GeV 2 11 GeV 8.8 GeV proton (NH3) x 11 GeV 8.8 GeV 0.3 < z < 0.7 W > 1.6 GeV Q 2 > 1.0 GeV 2 15

16 Impact of SoLID: Transversity Transversity distribution (Collinear & TMD) Chiral-odd: Unique for the quarks, no mixing with gluons, and simpler evolution effect. Collins asymmetry A transverse counter part to the longitudinal spin structure: helicity g 1L, but NOT the same. Couple to another chiral-odd function. (e.g. Collins function H1 ) SIDIS (E , E ), Drell-Yan Di-hadron (approved as run group with E ) Z.-B. Kang et al., Phys. Rev. D 93, (2016). M. Anselmino et al., Phys. Rev. D 92, (2015). 16 M. Radici et al., JHEP 05 (2015) 123.

17 Impact of SoLID: Transversity The improvement on transversity distributions SoLID proton target SoLID neutron target SoLID proton + neutron targets xh1(x) Q 2 =2.4 GeV 2 acceptance Q 2 =2.4GeV 2 KPSY15(u) KPSY15(d) After SoLID 0.8 δh SoLID /δh KPSY u d With both statistical and systematic errors 1 order of magnitude improvement x x x Ye, Sato, Allada, TL, Chen, Gao, Kang, Prokudin, Sun, Yuan, Phys. Lett. B 767, 91 (2017). 17

18 Impact of SoLID Data: Tensor Charge Tensor charge A fundamental QCD quantity: matrix element of local operators. Moment of the transversity distribution: valence quark dominant. Calculable in lattice QCD. SoLID impact Dyson-Schwinger equation Lattice QCD Models Phenomenology Future experiment With both statistical and systematic errors 1 order of magnitude improvement gd T gu T Pitschmann et al. (2015) Yamanaka et al. (2013) Bhattacharya et al. (2016) Abdel-Rehim et al. (2015) Gockeler et al. (2005) Cloet et al. (2008) Wakamatsu (2007) Pasquini et al. (2005) Gamberg, Goldstein (2001) Schweitzer et al. (2001) Ma, Schmidt (1998) Barone et al. (1997) Schmidt, Soffer (1997) He, Ji (1996) Kim et al. (1996) Kang et al. (2016) Radici et al. (2015) Goldstein et al. (2014) Anselmino et al. (2013) Ye et al. (2017) JLab12 SoLID

19 Tensor Charge and Neutron EDM Tensor charge and nedm 3 current g + current d T n 2 future g future g T T + current d n + future d n Electric Dipole Moment e cm -25 / 10 d u / 10 e cm d d Current neutron EDM limit: e cm, J.M.Pendlebury et al., Phys. Rev. D 92, (2015). Future neutron EDM experiments are expected to have the sensitivity of e cm. H. Gao, TL, Z. Zhao, arxiv:

20 Tensor Charge and Proton EDM Tensor charge and pedm 1 current g T future g future g T T + current d p + current d p + future d p e cm -24 / d u / 10 e cm d d Current proton EDM limit: e cm derived from mercury EDM. Future storage ring proton EDM experiment is expected to have the sensitivity of e cm. H. Gao, TL, Z. Zhao, arxiv:

21 Sivers distribution Sivers Distribution naively time-reversal odd. Test the sigh change M. Anselmino, M. Boglione, U. D Alesio, F. Murgia, A. Prokudin, JHEP 04 (2017)

22 Impact of SoLID: Sivers Projected data (example) Simultaneously fit to unpolarized and polarized data HERMES multiplicity data COMPASS, HERMES, JLab single spin asymmetry data preliminary result with a single fit xf?(1) 1T (x, Q 2 ) Error World / Error SoLID World vs. SoLID including systematics Q 2 =2.4 =2.n.4 GeV 2 Prelimi minary x On-going with N.Sato, A. Prokudin, W. Melnitchouk, Z. Ye, K. Allada, H. Gao, J.-P. Chen. 22

23 Monte Carlo Sampling Preliminary result with the nested sampling. xf1t (1) Preliminary x On-going with N.Sato, A. Prokudin, W. Melnitchouk, Z. Ye, K. Allada, H. Gao, J.-P. Chen. 23

24 Summary Lepton scattering is a powerful tool to probe the internal structure of the nucleon. Many efforts have been made in JLab 6-GeV SIDIS experiments. SIDIS experiments in JLab 12-GeV era, e.g. SoLID: high luminosity and large acceptance, multidimensional mapping with high precision. Transversity as an example: SoLID experiment will improve the precision by one order of magnitude. New physics: tensor charge together with next generation EDM experiments. Sivers as an example (ongoing): simultaneously fit to unpolarized and polarized data. Thank you! 24

25 Backup 25

26 Kinematics Differential Cross Section Analysis Systematic uncertainties: X. Yan et al., Phys. Rev. C 95, (2017). 26

27 Differential Cross Section Ratio X. Yan et al., Phys. Rev. C 95, (2017). 27

28 Tensor Charge Improvement by SoLID Z. Ye, N. Sato, K. Allada, T.L., J.-P. Chen, H. Gao, Z.-B. Kang, A. Prokudin, P. Sun, F. Yuan, Phys. Lett. B 767, 91 (2017). 28

29 Systematic Uncertainties Z. Ye, N. Sato, K. Allada, T.L., J.-P. Chen, H. Gao, Z.-B. Kang, A. Prokudin, P. Sun, F. Yuan, Phys. Lett. B 767, 91 (2017). 29