3-D Imaging and the Generalized Parton Distribution Program at an Electron Ion Collider

Transcription

1 Workshop on Precision Radiative Corrections for Next Generation Experiments 6 9 May 6, Jefferson Lab, Newport News VA 3-D Imaging and the Generalized Parton Distribution Program at an Electron Ion Collider Charles Hyde Old Dominion University

2 JLab Figure-8: Polarized p, D, 3He, Li electron: 3 to GeV Ions: to (GeV/c) Z. N=A, ~5 GeV/c per nucleon 48Ca 38U: ~4 GeV/u Luminosity maximal at ~ 4 GeV/c: L~ 33 34/cm/s Integrated Luminosity/year - fb Upgrade path to (GeV/c)

3 Full Acceptance Detector (-3m +45 m) Comprehensive Integration of Detector with Accelerator Lattice 3-D imaging: Far-Forward Ion Detect scattered beam particles for δp /p >.5 and/or θ > 3 mrad Nuclear Final States in Deep Inelastic Scattering: Neutrons in cone (.5 GeV/c)/(5 GeV/c) = mrad Charged particle fragments from δp/p = -.5 (protons) to δp/p = +.5 ( 3 H fragment in N=Z Nucleus)

4 JLEIC Central Detector TOF RICH EMCal HCal Forward Tracking Hadron Blind Barrel Tracker Region- SiVT DIRC TOF Dual RICH Forward EMCal

5 erhic ERL-Ring & Ring-Ring Designs Polarized p, 3He GeV x 5 GeV Staged Luminosity

6 erhic Interaction Region

7 x GeV: xb =.5, Q = GeV y =. Q (GeV) Example DVCS Estimates... xb γ + p γ + p γ + p γ + p 4 Ldt= fb GeV on GeV Ldt = fb- dσdvcs/dt (pb/gev) fb t (GeV) xb F(xB, bt) (fm-) < xb <.63 < Q/GeV < bt (fm) < xb <.6 < Q/GeV < t (GeV) xb F(xB, bt) (fm-) g/ αsg(x) dσdvcs/dt (pb/gev) GeV on 5 GeV bt (fm) Figure.: Top: The DVCS cross-section in two bins of x and Q. The error bars reflect statistical and assumed systematic uncertainties, but not the overall normalization uncertainty

8 Acceptance for p in ep->e Xp JLEIC Region ZEUS Leading Proton Spectrometer δp/p 3 p/gev δp/p 3 4 Region (Hi. Res) Zhiwen Zhao Acceptance in diffractive peak (X L >~.98) X L = Ep /Ep ZEUS: ~% JLEIC: ~% (also covers much higher X L at HERA) JLab EIC General Meeting, May 3, 6

9 JLEIC ZDC Acceptance p (GeV) t (GeV) Neutron Acceptance for ep->e Xn FNC Acceptance ~% geometrical accep. ZDC Zhiwen Zhao JLab EIC General Meeting, May 3, 6 Doubles kinematic coverage ~5- times acceptance compared to HERA

10 t (GeV ) t (GeV Figure 8: The differential cross section dσ/d t for γ p ρ p as t for W = 9 GeVand fixed values of Q. The lines represent expo the data. The data stem from ZEUS. Deep Virtual Meson Production HERA: DVCS, Vector-Meson t-slopes vs. Q+MV Leading twist GPD Sudakov suppression in γ V vertex S.Liuiti: Twist 3 GPD/DA dominates Deep Virtual π production for Q < 5 GeV. b(gev-) ZEUS 4 ρ ZEUS pb - ρ ZEUS 94 ρ ZEUS 95 ρ H φ ZEUS 98- φ ZEUS 94 J/ψ ZEUS 98- J/ψ ZEUS J/ψ H 96- DVCS H Q +M (GeV ) Figure 9: The slope b describing the t dependence of vectormeson the form γ p V p e b t as a function of (Q + MV ) where MV i

11 Deep Virtual Exclusive Scattering on the Nucleon u/d flavor separations: DVCS on proton Spectator tagging on D and 3 He ~ ~ H, H Longitudinal e and ion polarization E, E Transversely polarized ions u/d/s from DVES ~ ~ H, E from ᴨ/K H, E from ρ +,,, ω, K* gluons from Deep Virtual phi, J/Psi E glue from Transverse polarized beam

12 On-Shell Extrapolation EMC effect in tagged DIS Quasi-Free Neutron q Impulse Approximation p pn =(PD-pR) = t =AM t structure with (un)polarized deuterons and forward p n of+neutron study spectator ta α p t = (p p ) t > MD B + B/ 3 t > 4 GeV Example extrapolation k PD = 5 GeV xb [.5,.3], Q [,] GeV Ldt = /fb neutron X D proton R R, R D RT EMC effect in tagged DIS e + D e' + p + X, backward kinematics.5 modified unmodified on-shell 7 - Lint = nb, sen = GeV. Kinematic limit FD (tagged) (t ) / R x =.3-.4, Q = -3 GeV αr = (backward) t [GeV ] Figure. (Color online) Examples of reduced cross-section fit with the nd order of polynom of t. The very left side red circle shows the extrapolation point at t =. The vertical da

13 Exclusive Proceeses on Nuclei 97s Elastic (e,e ): Charge Fourier-Bessel Charge Form Factors F(q) Form Factor C 6 O 48 Ca 8 Pb 4 He G E,p distributions = valence quark distributions q (GeV/c)

14 Deep Virtual Coherent Processes Imaging the Matter Distributions of Nuclei,!! q(x, b)+q(x, b), J/! xg(x, b)? resolution from e.g. A Z(e, e! K + K ) A Z Veto on nuclear excitation

15 Unique Features of the EIC First ever polarized ea collider Large (~7%) transversely polarized light ions No target dilution (proton beam, not NH3 target) Full Acceptance (no target cryostat) Soft-Recoils and Target-Fragments are boosted forward by.5-.5 x (gamma-factor of beam) Separately tag high- or low-momentum target constituents Veto Target breakup > Tag rapidity gap events