EIC Science Rik Yoshida, EIC-Center at Jefferson Lab Abhay Deshpande, Center for Frontiers in Nuclear Physics, BNL and Stony Brook
Introduction Invited to give a talk EIC Science and JLEIC Status I will give 2 talks -This one EIC Science ~25 min - JLEIC status ~10 min After discussion with Abhay, we decided to give a different talk on EIC Science given the venue and audience. Abhay and I have been collaborating on a magazine article on EIC science. As EIC becomes more and more real, we will need to talk to people beyond nuclear physics, or even science. We thought it might be interesting to show what we have been thinking about to an expert audience. So this talk is co-authored by me and Abhay The second talk is a Jefferson Lab talk. EIC Science-INT Symposium 2018 2
Our Universe Observable universe contains about 10 53 kg of ordinary matter. Most of this mass is in about 10 80 protons and neutrons at the center of atoms. Where does the mass of the protons and neutrons come from? EIC Science-INT Symposium 2018 3
Higgs Boson Discovery In 2012, the Higgs Boson was discovered at the LHC at the CERN laboratory The Higgs mechanism gives mass to quarks, and protons (and neutrons) are made of quarks. BUT, it turns out that the quarks make up only about 1% of the proton mass. Where does the mass of the proton come from? EIC Science-INT Symposium 2018 4
Characteristics of the nucleons Quarks (and gluons) in protons are bound together by an interaction called Quantum Chromodynamics (QCD). The energy stored in the proton due to QCD interactions is responsible for the mass of the proton (E=mc 2, i.e. energy = mass times speed-of-light 2 ) But how exactly this happens is still a mystery! Spin In fact, we don t understand truly how any of the characteristics of the nucleon comes about from the fundamental QCD interactions. nucleon-nucleon forces EIC Science-INT Symposium 2018 5
Origin of Elements Characteristics of Protons and Neutrons (Nucleons), singly and collectively in Nuclei, in concert with EW and Gravity forms the visible Cosmos. Stellar Fusion Big Bang He through Fe Nova ~14 to 5 Billon Years ago H, He ~15 Billion Years ago Neutron stars ~250 Thousand Years ago Heavier than Fe EIC Science-INT Symposium 2018 6
Characteristics of Nucleons Nucleons Mass Spin Bulk NN interactions Arise out of quarks and gluons interacting through Quantum Chromodynamics (QCD) Nucleons are an emergent phenomena of QCD that we still don t really understand Fifty years after the discovery of the quarks, we are finally at the threshold of unraveling this mystery. This is the story of how we got here and where we re going next in this great adventure. EIC Science-INT Symposium 2018 7
Seeing Quarks and Gluons In the first part of the 20 th century we learned to see atoms using x-rays Double-Helix d ~ nanometers In the same way, we learned to see inside protons in the 1960 s using powerful electron beams. Electron acclerator at SLAC under construction femtometer EIC Science-INT Symposium 2018 8
Quantum Entanglement However, we have an immediate problem: Quantum Mechanics Atoms can be located at definite positions in space, with mostly empty space between them. Quarks and gluons are at a scale (1000000 smaller) which is deeply quantum mechanical: they exist only in superposition of infinite number of configurations. Worse: the tool that we use to probe the proton and the proton structure are quantum mechanically entangled and we can t tell them apart. How can we deal with this situation? EIC Science-INT Symposium 2018 9
Parton Model Feynman Imagine the proton is moving very (very) fast. Then the proton is flattened due to Lorenz contraction. Bjorken If the proton content ( partons ) is probed quickly enough then perhaps we can measure what fraction of the momentum the parton being probed (called Bjorken-x). We could then measure the x-distribution of partons? This turns out to be correct! EIC Science-INT Symposium 2018 10
Quantum Chromodynamics (QCD) Photons couple to electric charge. For QCD: electrons quarks photons gluons electric charge color gluons (unlike photons) carry charge and thus couple to gluons. EIC Science-INT Symposium 2018 11
Asymptotic Freedom and Confinement Gross, Politzer and Wilzcek (1973) Nobel Prize 2004 In high-energy interactions, quarks are weakly bound. QCD is a viable theory of quark interactions. partons = quarks is a viable hypothesis. Also implies quark-gluon plasma EIC Science-INT Symposium 2018 12
How and where we can solve QCD Protons Mass Spin Bulk NN interactions We still can t do the math! We can do the math! Lattice QCD sidebar EIC Science-INT Symposium 2018 13
Quantum Entanglement resolved (for Bjorken-x) As long as the the probe has small enough wavelength, the probe (the virtual photon) and the proton are not entangled. (factorization) This means we can measure the momentum distributions of quarks and gluons.. but in 1 direction only. The momentum distribution itself has its origins in the un-calculable part of QCD. So we gain an imperfect picture of the proton. EIC Science-INT Symposium 2018 14
Measuring x-distributions resolution smaller x How far can this rise go on? EIC Science-INT Symposium 2018 15
Large Hadron Collider Beam of quarks and gluons EIC Science-INT Symposium 2018 16
Learning to turn the proton Fast proton as seen from the side Fast proton seen head-on QCD Theory development in last 30 years New Factorization Old factorization EIC Science-INT Symposium 2018 17
First Transverse Structure Measurements worldwide DESY Laboratory, Germany CERN Laboratory, Switzerland HERMES experiment COMPASS experiment Brookhaven Laboratory, NY Brookhaven Laboratory, VA EIC Science-INT Symposium 2018 18
Advances in all areas means we are ready for the EIC Theory Accelerator Technologies Detector Technologies Computing Steady advances in all of these areas mean that EIC Science-INT Symposium 2018 19
US-Based EIC Proposals Jefferson Lab Newport News, VA 2002 JLab Concept Brookhaven Lab Long Island, NY EIC Science-INT Symposium 2018 20
EIC Science example: Spin Puzzle Try to gain dynamical understanding p b Momentum imaging (TMD s) Proton is transversely polarized Spatial Imaging (GPDs) Measure the quarks (and gluons) and relate this information to nucleon characteristics Imaging Measuring the correlations of position, momentum, spin, density: map the relationship between the parton state and the nucleon state. EIC Science-INT Symposium 2018 21
QCD at Extremes: Parton Saturation HERA discovered a dramatic rise in the number of gluons carrying a small fractional longitudinal momentum of the proton (i.e. small-x). This cannot go on forever as x becomes smaller and smaller: parton recombination must balance parton splitting. i.e. Saturation unobserved at HERA for a proton. (expected at extreme low x) In nuclei, the interaction probability enhanced by A ⅓ Will nuclei saturate faster as color leaks out of nucleons? EIC Science-INT Symposium 2018 22
Femtostructure vs. Nanostructure nanometers Highly relativistic Highly quantum mechanical Strongly coupled femtometers Unlike any other dynamical system we have studied. EIC Science-INT Symposium 2018 23
Modern Technology We live in a world that would have been unimaginable 100 years ago EIC Science-INT Symposium 2018 24
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 begins. The deep knowledge of atomic structures and electromagnetism is the basis of today s technology. Atomic- or nanotechnology. EIC Science-INT Symposium 2018 25
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? EIC Science-INT Symposium 2018 26
Structure of Matter Nanoworld (scale ~10-9 meters) A million times smaller Can we manipulate quarks and gluons? Femtoworld (scale ~10-15 meters) We have known for half a century that quarks (and gluons) and their interactions make up 99% of mass in the visible universe.. however.. no way to map quarks and gluons in the nucleus.. till now! EIC Science-INT Symposium 2018 27
Extra EIC Science-INT Symposium 2018 28
EIC Science: 3. Energy into Matter Investigate how energy turns into matter by using cold QCD matter as a detector Hadron Formation Color Neutralization Apply what is learned to HI EIC can scan through different configurations by changing the energy transfer. Understand, for the first time, time scales of hadronization. EIC Science-INT Symposium 2018 29