1. From Nuclei to Quarks and Gluons Exploration with EM Probes Zhihong Ye ( 叶志鸿 )

2. Outline: 2

3. The Structure of Matters 3 BabyDNAMolecularAtom Nucleus Nucleon

4. The Standard Model 4 QED ： Quantum ElectroDynamics (a precise theory, well studied theoretically and experimentally) QCD : Quantum ChromoDynamcs (precise but hard to calculate, need close works between theorists and experimentalists) +

5. Probe with Electron Scattering 5  Electron Scattering: A clean way (QED) to study complicated problems (QCD)! QEDQED and/or QCD Different processes of scattering on a target: Elastic Scattering: Treat the target as structure- less, and study its outer feature (like “visible light”) Inelastic Scattering: Break into the target and see the inner structure (like “X-Ray”) Quasi-elastic: see nucleons inside a nucleus Deep-inelastic: see quarks & gluons inside a nucleon X-Ray Visible Light Our eyes see matters via photons scattering on objects We also can “see” the nucleus/nucleon via scattering on them with high energy particles (photons, electrons, protons, neutrinos, etc.) By transferring higher energy on targets Other scattering processes: muon  target; meson  target; proton  target; electron  positron; proton  proton/ion; electron  proton/ion; Other scattering processes: muon  target; meson  target; proton  target; electron  positron; proton  proton/ion; electron  proton/ion;

6. Probe with Electron Scattering 6 Resolution vs. Wavelength Resolution vs. Energy Astronomy Particle Physics To “see” the more detailed structure in nuclei, we need higher transfer energy! Shorter Wavelength Higher Energy

7. Thomas Jefferson Lab Located at Newport News, Virginia; Funded by Department of Energy; First operation in 1990s Provide high energy, high intensity, high polarization electrons scattering on fixed targets in four experimental halls

8. Thomas Jefferson Lab 8 Hall-A Hall-B Hall-C Hall-D Super fast electron beams (12GeV)

9. The Size of a Proton 9 At low energy transfer, electrons “see” a proton as a point-like particle with an effective “charged radius”. The proton size “seen” by electron scattering agrees with the normal hydrogen lamb-shift results (CODATA) E0E0 E’ P0P0 P’ Muons see a skinny proton! (proton charged radius puzzle) The lamb-shift effect of electrons in the Hydrogen atom depends on the size of the proton, and can be precisely calculated by QED. A muon is just like a electron but heavier. What if it replaces the electron in Hydrogen? The proton charged radius can also been “indirectly” measured by electron scattering process. A 7σ deviation!

10. The Proton Charged Radius Experiment (PRad) in Hall-B:  High resolution, large acceptance, hybrid HyCal calorimeter (PbWO 4 and Pb-glass)  Q 2 range of 2x10 -4 – 2.0x10 -2 GeV 2 (lower than all previous electron scattering experiments.)  Simultaneous detection of elastic and Møller electrons  Windowless H2 gas flow target  GEM Chamber (first big GEM used at Jlab!)  Vacuum box, one thin window at HyCal only The Size of a Proton The experiment has been scheduled to take data in Spring 2016!

11. The Structure of Nucleus – SRC & EMC Effects 11  Electrons outside an atom are in different shells  Naively, due to the mean-field effect, nucleons inside a nucleus are also in different shells! A nucleon interact with others from different directions Equally like it is in a mean field  However ， nucleons interact far more complicated! These 2N-SRC and 3N-SRC nucleon-clusters have extremely high density; can help us to understand the core of a neutron star Short-Range Correlations (SRC)

12. The Structure of Nucleus – SRC & EMC Effects 12 R. Subedi, et al, Science 320 1476 (2008) Two JLab publications in Science are both related to SRC!  2N-SRC has been measured at SLAC and three halls in JLab. Protons prefer to stay closely with neutrons We study SRC with electron scattering on a nucleus, and study the knocked nucleon-pairs or measure the cross sections O. Hen et al., Science 346, 614 (2014).  3N-SRC has also been measured at three halls in Jlab which, however, have different results Z. Ye et al., “Search for three-nucleon short-range correlations”, to be submitted PRL on next month E08014  My thesis experiment done in Hall-A (planed to publish 2 papers on PRL and one on PRC) I am preparing a new experiment, E12-11-112, that will run on fall 2016 in Hall-A to continue measuring 3N-SRC

13.  Linear correlation! D.O.F: Nucleus  Nucleon  Quarks & Gluons ? EMC  How quarks&gluons form nucleons. SRC  How nucleons form nuclei.  Many theoretical developments try to explain EMC, but none is convicting  SRC vs. EMC suggests that the deformation of a nucleon is a results of high local density (e.g. a 6-quarks state)  Understanding how EMC connects to SRCs is one of the major missions at Jlab!  6 new experiments will be carried out in Hall-A and Hall-C in the next three years.  I am working on one EMC experiment, E12-10-103, to be ran in Spring 2017 EMC Effect: A nucleon changes its structure in different nuclei. “slope” in EMC  how significant a nucleon is deformed in a nucleus compared with one in the Deuterium. The Structure of Nucleus – SRC & EMC Effects slope

14. Typical Experiments in Hall-A@JLab HRS-L HRS-R Beam Line Target Detector Huts Hall-A

15. HRS-L HRS-R Beam Line Target Detector Huts Hall-A e (1~12 GeV) e’ Typical Experiments in Hall-A@JLab

16. W p u (x,k T,r T ) Wigner distributions d2rTd2rT TMD PDFs f 1 u (x,k T ),.. h 1 u (x,k T )‏ 3D Nucleon Tomography! GPDs/IPDs d2kTd2kT from GPD-H from TMD-Sivers Function Transverse Momentum Space Transverse Spatial Space 16 The 3D Structure of Nucleons  A nucleon can be ultimately described by the 6D wave-functions of quarks and gluons (3D in spatial space and 3D in momentum space, reduce to 5D in the relativistic regime, like Wigner distributions )  However, Paul-Blocking Principle doesn’t allow us to determine position and momentum at the same time! (we need to separately get the 3D spatial part and 3D momentum part) 5D 3D

17. ,K e e’ The 3D Structure of Nucleons 17 SIDIS: Detect scattered electrons and produced hadrons in the final state  The 3D momentum part is described by the Transverse Momentum Distributions (TMD)  TMD can be measured with Semi-Inclusive Deep Inelastic Scattering (SIDIS): Jlab-SoLID  TMD with Drell-Yan Process: I will participate the DY experiment at Fermi-Lab  The 3D spatial part is described by the Generalized Parton Distributions (GPD)  GPD can be measured with Deep Virtual Compton Scattering (DVCS) and others: Jlab-SoLID I am leading the development of three proposals to measure GPD with Jlab-SoLID.  Spin of a nucleon: Ji’s Nucleon Spin Decomposition: DIS TMD+GPD Need EIC! Quark Spin only contribute 30% of the nucleon spin! What are the rests.

18. SoLID  Solenoidal Large Intensity Device (proposed to build in Hall-A) High Intensity (10 37 ~ 10 39 cm -2 s -1 ) and, Large Acceptance (8<θ<24, 0<Φ<360, 1<Pe<7GeV/c for SIDIS) Two Configurations & GPD 18

19. SoLID-SIDIS Detectors MRPC EC HGC LGC 100cmx50cm Double-mask GEM foil 40cmx40cm Single-mask GEM foil in CAIE 19 by USTC&Qinghua by UVa/Qinghua/Shangdong by CAIE & USTC & Qinghua & Lanzhou …

20. My Role in SoLID Leading the development of TMD physics with SIDIS (working closely with theorists to study the TMD extraction and predict the impact of SoLID-SIDIS data to TMDs. A paper will be published to PRL on next spring) Leading the development of GPD physics using SoLID (will be the spokesperson and contact person of two SoLID-DVCS proposals, plus more) Working on a new proposal to study EMC effect using Parity Violation Deep Inelastic Scattering. (will be one of the spokespersons )  Core member of the SoLID Geant4 simulation team and software team  Working on detector R&D and testing; Supervising graduate students (mainly responsible for the MRPC and SPD detectors)  Leading the background simulation and evaluation of SIDIS experiments; Optimizing systems.  Helping and organizing the regular collaboration activities About SoLID  Three Approved SIDIS Experiments + more bonus expeirments  Parity Violation Deep Inelastic Scattering (PVDIS): PVDIS-EMC with Calcium (will be proposed)  J/ψ : Near Threshold Electroproduction of J/ψ at 11 GeV:  Generalized Parton Distributions (GPDs): (new LOIs & Proposals)  A new run-group proposal was just approved: Time-Like Compton Scattering  polarized-proton/neutron DVCS, Doubly DVCS, DVMP, TCS, etc.  More e.g., Hadronization A $60Millinion Project. Big collaboration ( 200+ collaborators from 50+ institutes and 11 countries, and the number is still growing rapidly) Very strong contributions from Chinese Institutions (GEMs, MRPC, EC, SPD)

21. Scintillating Fiber Tracker 21  Proposed this new tracker when I was at Duke University for the PRad experiment  Awarded by Jefferson Science Associate Postdoc Fellowship with grant  Many applications in nuclear physics and medical physics (can be commercialized)  Continuously improving the design and working on building a prototype  Proposed this new tracker when I was at Duke University for the PRad experiment  Awarded by Jefferson Science Associate Postdoc Fellowship with grant  Many applications in nuclear physics and medical physics (can be commercialized)  Continuously improving the design and working on building a prototype 2014 JSA Postdoc Prize  Good Time Response: faster than Drift Chamber and GEM;  Without support systems:  Easy Handling: installed, stored and transported; work in vacuum or high EM field;  Easy Analysis: just need to know which SciFi is fired Scintillating Fibers (SciFi): A core of scintillating materials with one or several layers of thin cladding with lower index of refraction;

22. Scintillating Fiber Tracker 22 My lab at Jefferson Lab I am building another lab at Argonne National Lab to continue the prototyping

23. 4mm Scin. Strip+SiPM Fiber+SiPM Mounting Block SiPMs with Pre-Amp (Hall-D) SiPMs with Pre-Amp (Stepan@Hall-B) High Precision Power Supply (Hall-D) x2 Low Voltage Power Supplies (Hall-A&-D) Black Box (from Simona Malace) Temperature Sensor Thank you, Walter Kellner! Prototype Test Project: SiPM Test 23 Fan Sr90 SiPM  Silicon Photon Multiplier, Avalanche Photodiode (APD) pixels working in Geiger-mode Hamamatsu Multi-Pixels Photon Counter

24. Prototype Test Project: Application 24 My design has been adopted by the DarkLight Collaborators at Jlab who are preparing a dark photon search experiment on next year. Helping the MIT group to design and build their Center SFT. My design has been adopted by the DarkLight Collaborators at Jlab who are preparing a dark photon search experiment on next year. Helping the MIT group to design and build their Center SFT. DarkLight Detector Layout My big dream is to build a portable medical imaging device based on SFT! Typical Medical Imaging device GeoTomography Technologies

25. Summary 25