EJB April 2006 Nuclear Science: The Mission Understand the origin, evolution, and structure of the baryonic matter of the Universe Cosmic accelerationRotation curves & lensing Stars, planets, Human life from M. Ramsey-Musolf, Caltech

EJB April 2006 FUNDAMENTAL PARTICLES+INTERACTIONS redux

EJB April 2006 Some of the Big Questions of Nuclear Physics Hot Dense Matter and Phase Transitions (What are the phases, how did the early universe behave?) QCD and the Structure of Matter (How are nucleons constructed from quarks and gluons, what about nuclei? ) Fundamental Symmetries ( ’s, neutron beams, radioactive ion traps) Origins of the Elements (How are elements formed in stars, how do stars burn, what are the limits of stability?)

EJB April 2006 heavynuclei fewbody quarksgluons vacuum relativistic heavy ions electronscattering stable and radioactivebeams Modern Tools of Nuclear Physics From W. Nazarewicz, ORNL

EJB April 2006 neutrons protons rp process r process Mass known Half-life known nothing known s process stellar burning Big Bang p process Supernovae Cosmic Rays H(1) Fe (26) Sn (50) Pb (82) What is the Origin of the Elements? from MSU Phys 983 web site Supernova E Time (s) X-ray burst Frequency (Hz) U n-Star KS

EJB April 2006 Relativistic Heavy Ion Collider, Brookhaven, NY Search for evidence of transition from nucleons to “free” quarks + gluons at very high energy density.

EJB April 2006 Hot Dense Matter PHENIX detector compare d-Au collisions with Au-Au collisions

EJB April 2006 Fundamental Symmetries of Nature a trapped 21 Na atom at Berkeley Nuclear Physics is a Tool test time reversal invariance unitarity of quark mixing neutron lifetime -> He abundance atomic trapping of radioactive atoms neutron decay solar neutrino mixing showed that neutrinos have mass what are the masses? Are there more than 3 types? Sudbury Neutrino Observatory (SNO)

EJB April 2006 J efferson Laboratory, Newport News, VA A 6 GeV continuous electron beam accelerator superconducting RF cavities First beam in experimental halls people per experiment Research program hadron structure properties of light nuclei strangeness in nuclei

EJB April 2006 (, q )  Atomic Structure and Quantum Electrodynamics = p e Energy Levels of H: (Lamb shift) (Fine structure) (Bohr Model) + …

EJB April 2006 QCD and the Structure of Matter Strong interaction  QCD  can also have: do not exist in QED! e.g. Proton: u + u + d  Q p = 2(2/3) + (-1/3) = 1 Neutron: u + d + d  Q n = (2/3) + 2(-1/3) = 0 BUT:quarks are very light and relativistic gluons carry angular momentum interaction is STRONG and INCREASING with distance  s  1

EJB April 2006 Ground State Structure of Matter Example 1: Hydrogen atom M H = (7) amu = (6) MeV M p = (28) MeV m e = (15) MeV Ionization energy = 13.6 eV = M H Example 2: pion M  = (35) MeV m u  4 MeV m d  7 MeV (m u +m d )  0.1 M  Example 3: proton M p = (28) MeV (2m u +m d )  M p

EJB April 2006 Determining the structure of small things  d  d visible:  ~ 500 nm, E ~ few eV  atomic structure X-rays:  ~ nm, E ~ few keV  crystallography gamma rays:  < 0.1 nm E ~ MeV (10 6 eV)  nucleons inside nuclei E ~ GeV (10 9 eV)  quark structure of nucleons De Broglie Wavelength:  ~ h/p ( ~ hc/E) (1 electron-Volt = x Joules)

EJB April 2006 Theoretical Tools Effective field theory lattice QCD find “effective” degrees of freedom to relate observation to measurement. Works well for 2 nucleons, not so well for > 2. perturbative QCD quarks + gluons are weakly interacting at high energy. Can use successive approximations “brute force”: large scale computing Put quarks on a grid in (x,y,z,t), compute interactions, build nucleon measurements are guide

EJB April 2006 G0 Apparatus One octant’s scintillator array 20 cm LH 2 Target determine how strange quarks contribute to proton’s charge

EJB April 2006 Applications of Nuclear Physics (and NP training) Nuclear medicine and medical imaging oil exploration/geophysics materials development w/ neutron beams homeland security (detection of radioactive materials) environmental science (waste transmutation, nonproliferation) teaching advanced computation and simulation technical consulting and management the stock market (!) science policy in government

EJB April 2006 Nuclear Science: Ten Questions 1.Why is there more matter than anti-matter ? 2.How do the properties of baryons, leptons and their interactions reflect the symmetries of the early Universe? 3.What is the nature of baryonic matter at the highest temperatures and densities ? 4.How do the properties of the vacuum evolve with temperature? 5.How is the nucleon assembled from the quarks and gluons of the Standard Model? 6.How do the interactions between quarks and gluons give rise to the properties of light nuclei? 7.How do the properties of complex nuclei arise from the elementary NN interaction? 8.What are the limits of nuclei and atoms? 9.How does the physics of nuclei impact the physical Universe (origin of heavy elements)? 10.How does the physics of nuclei impact the physical Universe (neutron stars, supernovae, neutrinos…)?