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Overview of the Future Programs at JLAB and EIC Overview of the future programs at JLAB and EIC Jianwei Qiu Theory Center, Jefferson Lab JeffersonOutline Lab of 12 the GeV rest Upgrade of my talk Project The 12 GeV Upgrade greatly expands the research capabilities of Jefferson Lab, adding a fourth experimental hall – D, upgrading existing halls and doubling the power of the lab's accelerator. Maintain capability to delier lower pass beam energies: 2.2, 4.4, 6.6, … Project Scope • Doubling the accelerator beam energy – DONE • New experimental Hall D and beam line – DONE • Civil construction including utilities – DONE TPC = $338M • Upgrades to Experimental Halls B & C – ~99% 99% complete! • Halls B & C Detectors – DONE JLabOutline 12 GeV of Scientificthe rest of Capabilities my talk Outline of the rest of my talk q The next QCD frontier – the “big” questions, … q JLAB12 and the Electron-Ion Collider (EIC) q How JLAB12/EIC could answer the “big” questions? q Path forward to the EIC era – unique role of JLAB12 q Summary The next QCD frontier q What is the role of QCD in the evolution of the universe? q How hadrons are emerged from quarks and gluons? q How does QCD make up the properties of hadrons? Their mass, spin, magnetic moment, … q What is the QCD landscape of nucleon and nuclei? Color Confinement Asymptotic freedom Q (GeV) 200 MeV (1 fm) 2 GeV (1/10 fm) Probing momentum q How do the nuclear force arise from QCD? q ... Have to understand the role of glue! The next QCD frontier q Understanding the glue – the Next QCD Frontier! q Gluons are weird particles! ² Massless, yet, responsible for nearly all visible mass “Mass without mass!” Bhagwat & Tandy/Roberts et al The next QCD frontier q Understanding the glue that binds us all – the Next QCD Frontier! q Gluons are weird particles! ² Massless, yet, responsible for nearly all visible mass ² Carry color charge, responsible for color confinement and strong force The next QCD frontier q Understanding the glue that binds us all – the Next QCD Frontier! q Gluons are weird particles! ² Massless, yet, responsible for nearly all visible mass ² Carry color charge, responsible for color confinement and strong force but, also for asymptotic freedom Nobel Prize, 2004 QCD perturbation theory The next QCD frontier q Understanding the glue that binds us all – the Next QCD Frontier! q Gluons are weird particles! ² Massless, yet, responsible for nearly all visible mass ² Carry color charge, responsible for color confinement and strong force but, also for asymptotic freedom, as well as the abundance of glue The next QCD frontier q Understanding the glue that binds us all – the Next QCD Frontier! q Gluons are weird particles! ² Massless, yet, responsible for nearly all visible mass ² Carry color charge, responsible for color confinement and strong force but, also for asymptotic freedom, as well as the abundance of glue JLAB12 Without gluons, there would be EIC NO nucleons, NO atomic nuclei… NO visible world! Unprecedented Intellectual Challenge! q Facts: ² We measure/detect leptons and hadrons ² No modern detector has been able to see quarks and gluons in isolation! q The challenge: How to probe the quark-gluon dynamics, quantify the hadron structure, study the emergence of hadrons, …, if we cannot see quarks and gluons? q Answer to the challenge: Theory advances: QCD factorization – matching the quarks/gluons to hadrons with controllable approximations! Experimental breakthroughs: Energy, luminosity and measurement – Unprecedented resolution, event rates, and precision probes, especially EM probes, … Quarks – Need the probe to “see” their existence, … Gluons – Varying the probe’s resolution to “see” their effect, … Jets – Footprints of energetic quarks and gluons QCD factorization is an approximation q Cross section with identified hadron(s) is NON-Perturbative! 2 2 2 σDIS(x, Q )= = + + + +… = + + + +… 2 2 2 2 = cq q(x, Q )+cg g(x, Q )+cqg Tqg( x ,Q )+cgg Tgg( x ,Q ) ⌦ ⌦ ⌦ { } ⌦ { } Probe structure + kn /Qn, F 2n /Qn + ... O h T i h i Leading power Linear contribution Power corrections Non-Linear contribution DGLAP regime … Multi-parton correlations k2 F 2 c q(x, Q2)+c g(x, Q2)+ h T i, h i,.. Non-perturbative ⇡ q ⌦ g ⌦ O Q2 Q2 ✓ ◆ physics neglected Approximation – Leading power/twist factorization! or in input PDFs! How to “see” and quantify the hadron structure? q EM probe: Not a camera! Collision by photon exchange with a large momentum transfer: Q e.g. Photon momentum: q2 = – Q2 in DIS q Resolution: 1/Q ~ 1/10 fermi = 10-14 cm = 2 GeV-1 1/Q Breit frame (Brick-Wall frame) in DIS: 1/Q q =(q0,q ,qz)=(0, 0 , Q) ? ? − p =(Q/2, 0 ,Q/2) ? xB = x = Q/(2Pz) 1/P / z Resolution in Breit frame: q High energy: boosted partonic structure Could be the P P1 1 same as this! Time dilation! JLAB12 & the Electron-Ion Collider (EIC) q A giant “Microscope”: – “see” quarks/gluons and their dynamics by breaking the hadron γ*, Z0, .. e p 1/Q Q < 1/10 fm “see” the non-linear dynamics of the glue! q A sharpest “CT”: – “imagine” the quark/gluon structure without breaking the hadron – “cat-scan” the nucleon and nuclei with better than 1/10 fm resolution – “see” the proton “radius” of quark/gluon density JLAB – Valence region – “explore” the range of color force EIC – Sea & gluons Many complementary probes at one facility q High energy and luminosity Lepton-hadron facility: Q2 àMeasure of resolution y à Measure of inelasticity x à Measure of momentum fraction of the struck quark in a proton Q2 = S x y Inclusive events: e+p/A à e’+X Detect only the scattered lepton in the detector Semi-Inclusive events: e+p/A à e’+h(π,K,p,jet)+X Detect the scattered lepton in coincidence with identified hadrons/jets Exclusive events: e+p/A à e’+ p’/A’+ h(π,K,p,jet) Detect every things including scattered proton/nucleus (or its fragments) How to answer the “big” questions? q How does QCD generate the nucleon mass? “… The vast majority of the nucleon’s mass is due to quantum fluctuations of quark-antiquark pairs, the gluons, and the energy associated with quarks moving around at close to the speed of light. …” The 2015 Long Range Plan for Nuclear Science q Hadron mass from Lattice QCD calculation: Input How does QCD generate this? The role of quarks vs that of gluons? If we do not understand proton mass, we do not understand QCD How to answer the “big” questions? q Three-pronged approach to explore the origin of hadron mass ² Lattice QCD ² Mass decomposition – roles of the constituents ² Model calculation – approximated analytical approach https://phys.cst.temple.edu/meziani/proton-mass-workshop-2016/ How to answer the “big” questions? q Three-pronged approach to explore the origin of hadron mass ² Lattice QCD ² Mass decomposition – roles of the constituents ² Model calculation – approximated analytical approach http://www.ectstar.eu/node/2218 How to answer the “big” questions? q How does QCD generate the nucleon mass? “… The vast majority of the nucleon’s mass is due to quantum fluctuations of quark-antiquark pairs, the gluons, and the energy associated with quarks moving around at close to the speed of light. …” The 2015 Long Range Plan for Nuclear Science q Role of quarks and gluons? ² QCD energy-momentum tensor: ² Trace of the QCD energy-momentum tensor: β(g) T ↵ = F µ⌫,aF a + m (1 + γ ) ↵ 2g µ⌫ q m q q q=Xu,d,s QCD trace anomaly β(g)= (11 2n /3) g3/(4⇡)2 + ... − − f ² Mass, trace anomaly, chiral symmetry break, and … J/Ψ, Υ, … p T µ⌫ p pµp⌫ p T µ⌫ p (g ) pµp⌫ (g )=m2 h | | i/ h | | i µ⌫ / µ⌫ 2 ↵ β(g) 2 m p T ↵ p p F p /h | | i 2g h | | i Heavy quarkonium production near the threshold, from JLab12 to EIC How to answer the “big” questions? q How does QCD generate the nucleon’s spin? 1 1 = ⌃ +∆G +(L + L ) 2 2 q g Proton Spin Quark helicity Best known Gluon helicity Start to know Orbital Angular Momentum of quarks and gluons 30% Little known ⇠ 20%(with RHIC data) Spin “puzzle” ⇠ If we do not understand proton spin, we do not understand QCD How to answer the “big” questions? q How does QCD generate the nucleon’s spin? 1 1 = ⌃ +∆G +(L + L ) 2 2 q g Proton Spin q What can JLab12 and EIC do? CLAS12 Plus many more JLab12 experiments – flavor New role of the lattice calculations Lattice QCD X-dep distributions q New ideas – from quasi-PDFs (lattice calculable) to PDFs: ² High Pz effective field theory approach: Ji, et al., 1 2 2 arXiv:1305.1539 2 dy x µ 2 ⇤ M q˜(x, µ ,Pz)= Z , q(y, µ )+ , y y P O P 2 P 2 1404.6680 Zx ✓ z ◆ ✓ z z ◆ ² QCD collinear factorization approach: Ma and Qiu, 1 dy x µ2 1 arXiv:1404.6860 q˜(x, µ2,P )= , ,P f(y, µ¯2)+ 1412.2688 z y Cf y µ¯2 z O µ2 f Z0 ✓ ◆ ✓ ◆ Ishikawa, Ma, Qiu, X Yoshida, 1609.02018 Non-perturbative lattice UV renormalization: Monohan, Orginos, Effective mass renormalization, Gradient flow, … 1612.01584 … q The TMD Collaboration + on-going effort around the world! Plus the intense JLab and world-wide theory effort! New role of the lattice calculations Lattice QCD X-dep distributions q New ideas – from quasi-PDFs (lattice calculable) to PDFs: ² High Pz effective field theory approach: Ji, et al., 1 2 2 arXiv:1305.1539 2 dy x µ 2 ⇤ M q˜(x, µ ,Pz)= Z , q(y, µ )+ , y y P O P 2 P 2 1404.6680 Zx ✓ z ◆ ✓ z z ◆ ² QCD collinear factorization approach: Ma and Qiu, 1 dy x µ2 1 arXiv:1404.6860 q˜(x, µ2,P )= , ,P f(y, µ¯2)+ 1412.2688 z y Cf y µ¯2 z O µ2 f Z0 ✓ ◆ ✓ ◆ Ishikawa, Ma, Qiu, X Yoshida, 1609.02018 Non-perturbative lattice UV renormalization: Monohan, Orginos, Effective mass renormalization, Gradient flow, … 1612.01584 … q Tremendous potentials! PDFs of proton, neutron, pion, …; TMDs, GPDs, …; JLab12 expts How to answer the “big” questions? q How does QCD generate the nucleon’s spin? 1 1 = ⌃ +∆G +(L + L ) 2 2 q g Proton Spin To understand the proton spin, fully, we need to understand the confined motion of quarks and gluons in QCD TMDs, GTMDs, … Need “probes” for two-scale observables! Two-momentum-scale observables q Cross sections with two-momentum scales observed: Q Q 1/R ⇤ 1 2 ⇠ ⇠ QCD ² Hard scale: Q 1 localizes the probe to see the quark or gluon d.o.f.
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