Quarks Gluons and the Origin of Mass

Mumbai U. September 19, 2017 Outline

• Historical Introduction

• The Modern Proton

• Future Directions → imaging at the femtoscale

• Conclusion and Outlook Modern Technology

We live in a world that would have been unimaginable 100 years ago

(R. Yoshida) But 100 years ago…

William Henry Bragg (ca. 1915)

We learned to map atoms inside matter using x-ray crystallography. This is where it all began. The deep knowledge of atomic structures and electromagnetism is the basis of today’s technology. Atomic- or nanotechnology. (R. Yoshida) Limits of Nanotechnology: Atoms

Microelectronics improve with reduction of the “feature size”

We are now down to 10 nanometers. (about 100 atoms wide). Progress becomes more and more difficult. 2015 International Technology Roadmap for Semiconductors Can we go smaller?

(R. Yoshida) 1911 – Rutherford Atom

• Revolutionized our view of the atom • The power of charged particle scattering 1920’s – Otto Stern

"for his contribution to the development of the molecular ray method and his discovery of the magnetic moment of the proton". → proton is not a point particle 1950’s – Robert Hofstadter

"for his pioneering studies of electron scattering in atomic nuclei and for his thereby achieved discoveries concerning the structure of the nucleons" The Quark Model – M. Gell-Mann

• Finite size of nucleon • Patterns of known baryons and mesons

"for his contributions and discoveries concerning the classification of elementary particles and their interactions" 1960’s - Discovery of Quarks

The Nobel Prize in Physics 1990 was awarded jointly to Jerome I. Friedman, Henry W. Kendall and Richard E. Taylor "for their pioneering investigations concerning deep inelastic scattering of electrons on protons and bound neutrons, which have been of essential importance for the development of the quark model in particle physics". Quantum Chromodynamics (QCD)

• 1960’s – SLAC electron scattering results show small point-like constituents in the proton (Rutherford redux!) • 1970’s – theoretical development of QCD, analogous to QED Modern View of the Proton

• Extended object (1 fm ~ 10-13cm)

• Quarks (charged) & gluons (neutral)

• Quark-antiquark pairs (from gluons)

• Spin, orbital angular momentum

Sum of quark masses « proton mass (~2%) QCD and the Origin of Mass

 99% of the proton’s mass/energy is due to the self-generating gluon field – Higgs mechanism has almost no role.

 The similarity of mass between the C.D. Roberts, Prog. Part. Nucl. Phys. 61 (2008) 50-65 proton and neutron arises from the fact that the gluon dynamics are the same – Quarks contribute almost nothing.

 Lattice and model calculations now explicitly display dynamical breaking of chiral symmetry Advances in Femto-science

Theory

Accelerator Technologies

Detector Technologies Computing

Steady advances in all of these areas mean that  (R. Yoshida) Nuclear Femtography

The science of mapping the position and motion of quarks and gluons in the nucleus.

.. is just beginning

(R. Yoshida) Probing the Femto-world

Can’t use any ordinary probes: Atoms that make up ordinary instruments are a million billion times too big!

(R. Yoshida) Advancing Accelerator Technology:

From SLAC to CEBAF

SLAC (1960’s) Water-cooled Cu Original design for “continuous wave” (CW) beam CEBAF (1980’s) LHe cooled superconducting Nb Jefferson Lab Accelerator Complex

Cryomodules in the accelerator tunnel Superconducting radiofrequency (SRF) cavities

Hall D

Machine Control Center Hall C

An aerial view of the recirculating linear accelerator and 4 experimental halls. Jefferson Lab 12 GeV Upgrade

Total Project Cost = $338M Estimate to Complete < $1M

• Double maximum Accelerator energy to 12 GeV • Ten new high gradient cryomodules • Double Helium refrigerator plant capacity • Civil construction and upgraded utilities • Add 10th arc of magnets for 5.5 pass machine • Add 4th experimental Hall D • New experimental equipment in Halls B, C, D Jefferson Lab @ 12 GeV Science Questions

excited gluon field • What is the role of gluonic excitations in the spectroscopy of light mesons?

• Where is the missing spin in the nucleon? Role of orbital angular momentum?

• Can we reveal a novel landscape of nucleon substructure through 3D imaging at the femtometer scale?

• Can we discover evidence for physics beyond the standard model of particle physics? Gluonic Excitations and the Mechanism for Confinement

Excited Glue

Hall D@JLab

States with Exotic Quantum Numbers

Searching for the rules that govern hadron construction M. R. Sheperd, J. J. Dudek, R. E. Mitchell Quantum Numbers of Hybrid Mesons

Excited Quarks Hybrid Meson  Gluon Field

S  0    PC 1 PC 1 L  0 J   J       J PC  0 1 1 like , K

Exotic S  1    0 1 2 L  0 J PC      J PC  1 0 1 2 like ,

Gluonic excitation (and parallel quark spins) lead to exotic JPC The Incomplete Nucleon: Spin Puzzle

1 1 = DS + L + J 2 2 q g

[X. Ji, 1997]

• DIS → DS  0.25

• RHIC + DIS → DG~0.2

• → Lq “Nuclear Femtography”

5D • Transverse Momentum Dist. (TMD) – Confined motion in a nucleon (semi-inclusive DIS)

3D • Generalized Parton Dist. (GPD) – Spatial imaging (exclusive DIS)

• Requires – High luminosity – Polarized beams and targets – Sophisticated detector systems

Major new capability with JLab @ 12 GeV Extraction of GPD’s

Cleanest process: Deeply Virtual Compton Scattering hard vertices

s  s Ds A = s s = 2s ξ=xB/(2-xB) t Polarized beam, unpolarized target: ~ DsLU~ sinf{F1H+ ξ(F1+F2)H+kF2E}df H(x,t)

Unpolarized beam, longitudinal target: ~ ~ DsUL~ sinf{F1H+ξ(F1+F2)(H+ξ/(1+ξ)E)}df H(x,t)

Unpolarized beam, transverse target: E(x,t) DsUT~ sinf{k(F2H – F1E)}df SIDIS Electroproduction of Pions

• Separate Sivers and Collins effects • Previous data from HERMES,COMPASS • New landscape of TMD distributions • Access to orbital angular target angle momentum hadron angle

• Sivers angle, effect in distribution function: (fh-fs)

• Collins angle, effect in fragmentation function: (fh+fs) Nuclear Science Long-Range Planning

• Every 5-7 years the US Nuclear Science community produces a Long- Range Planning (LRP) Document

2015

We recommend a high-energy high- luminosity polarized Electron Ion Collider as the highest priority for new facility construction following the completion of FRIB.

27 Why Electron-Ion Collider?

Higher the collision energy, smaller the probe.

CEBAF 12 GeV Probe about 40th of the proton diameter

Electron-Ion Collider: Probe about 500th of the proton diameter Improving Resolution

Current situation CEBAF 12 GeV Electron-Ion Collider

Resolution is a few Resolution is 10’s times smaller than Resolution is 100’s target of times smaller than of times smaller than the target the target High Brightness Machine

100 times brighter

HERA: last electron-proton collider The New Landscape Enabled by EIC

• High Luminosity  1034 cm-2s-1

• Low x regime x  0.0001

1E+38

1E+37

1 1E+36 • High Polarization -

1E+35

sec.  70% 2 - 1E+34 JLab EIC 1E+33 12 1E+32 COMPASS Discovery 1E+31 HERA (no p pol.)

1E+30 EMC HERMES Luminosity cm. Luminosity 0.0001 0.001 0.01 0.1 1 Potential! x US-Based EIC Proposals

Brookhaven Lab Long Island, NY

Jefferson Lab Newport News, VA EIC at Jefferson Lab

JLab EIC Figure 8 Concept • High Polarization • High Luminosity • Low technical risk • Flexible timeframe for construction consistent w/running 12 GeV CEBAF • Cost effective operations

 Fulfills White Paper Requirements • Collaboration with SLAC, LBNL, ANL, BNL

• Site evaluation (Virginia funds) 1035

LHC

• User group organizing (charter, meetings) ( 34 • NAS study underway 10 • DOE-NP accelerator R&D program

(FY17-18) 1033 EIC Users Group and International Interest

Formed 2016, currently: 705 members 162 institutions, 29 countries Outlook

• The last century has seen revolutionary progress in mankind’s ability to - image the structure of matter - manipulate the parts to develop technology

• We are on the threshold of, for the first time, realizing the ability to image matter on the femtometer scale! - JLab12 (now) - EIC (future)

• Could this ultimately lead to an era of “femtotechnology”?

Only time will tell….

(Thanks to R. Yoshida)