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Nuclear Science: The Mission

Rotation curves & lensing. Cosmic acceleration. Stars, planets, Human life. Nuclear Science: The Mission. Understand the origin, evolution, and structure of the baryonic matter of the Universe. from M. Ramsey-Musolf, Caltech. FUNDAMENTAL PARTICLES+INTERACTIONS redux.

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Nuclear Science: The Mission

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

  2. FUNDAMENTAL PARTICLES+INTERACTIONS redux

  3. 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 (n’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?)

  4. stable and radioactive beams electron scattering relativistic heavy ions heavy nuclei few body quarks gluons vacuum Modern Tools of Nuclear Physics From W. Nazarewicz, ORNL

  5. X-ray burst Mass known 4U1728-34 Half-life known s process nothing known 331 Pb (82) 330 Frequency (Hz) 329 p process 328 327 r process 10 15 20 Time (s) Supernova Sn (50) rp process Fe (26) E0102-72.3 n-Star Supernovae stellar burning Cosmic Rays protons H(1) Big Bang neutrons KS 1731-260 What is the Origin of the Elements? from MSU Phys 983 web site www.nscl.msu.edu/~schatz/PHY983/topics.htm

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

  7. Hot Dense Matter compare d-Au collisions with Au-Au collisions PHENIX detector

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

  9. Jefferson Laboratory, Newport News, VA A 6 GeV continuous electron beam accelerator superconducting RF cavities First beam in 1995 3 experimental halls 50-100 people per experiment Research program hadron structure properties of light nuclei strangeness in nuclei

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

  11. QCD and the Structure of Matter Strong interaction  QCD as 1 • can also have: do not exist in QED! e.g. Proton: u + u + d Qp = 2(2/3) + (-1/3) = 1 Neutron: u+ d + d Qn = (2/3) + 2(-1/3) = 0 BUT:quarks are very light and relativistic gluons carry angular momentum interaction is STRONG and INCREASING with distance

  12. Ground State Structure of Matter Example 1: Hydrogen atom MH = 1.00794(7) amu = 938.89(6) MeV Mp = 938.27231(28) MeV me = 0.51099906(15) MeV Ionization energy = 13.6 eV = 10-8 MH Example 2: pion • Mp+ = 139.57072(35) MeV • mu 4 MeV • md 7 MeV • (mu+md)  0.1 Mp Example 3: proton Mp = 938.27231(28) MeV (2mu+md)  0.015 Mp

  13. Determining the structure of small things l d l d De Broglie Wavelength:l ~ h/p (~ hc/E) visible:l ~ 500 nm, E ~ few eV  atomic structure X-rays:l ~ 0.01-1 nm, E ~ few keV  crystallography gamma rays:l < 0.1 nm E ~ MeV (106 eV)  nucleons inside nuclei E ~ GeV (109 eV)  quark structure of nucleons (1 electron-Volt = 1.602 x 10-19 Joules)

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

  15. One octant’s scintillator array G0 Apparatus 20 cm LH2 Target determine how strange quarks contribute to proton’s charge

  16. 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

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

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