* Your assessment is very important for improving the workof artificial intelligence, which forms the content of this project
Download PowerPoint file - University of Regina
Renormalization wikipedia , lookup
Weakly-interacting massive particles wikipedia , lookup
Minimal Supersymmetric Standard Model wikipedia , lookup
Theory of everything wikipedia , lookup
Atomic nucleus wikipedia , lookup
ATLAS experiment wikipedia , lookup
Monte Carlo methods for electron transport wikipedia , lookup
Compact Muon Solenoid wikipedia , lookup
Mathematical formulation of the Standard Model wikipedia , lookup
Electron scattering wikipedia , lookup
Nuclear structure wikipedia , lookup
Grand Unified Theory wikipedia , lookup
Nuclear force wikipedia , lookup
ALICE experiment wikipedia , lookup
Peter Kalmus wikipedia , lookup
Renormalization group wikipedia , lookup
Technicolor (physics) wikipedia , lookup
Standard Model wikipedia , lookup
Elementary particle wikipedia , lookup
Future Circular Collider wikipedia , lookup
Light-front quantization applications wikipedia , lookup
Key Scientific Issues in Hadron Physics November 6-9, 2000 Duck, NC (Curtis A. Meyer) QCD fundamentals. The quark structure of matter seen using PQCD and elastic form factors The quark structure of matter as seen using spectroscopy. The quark structure of matter as seen using chiral dynamics Models of the quark structure of matter Key Issues in Hadron Physics QCD Participants at the Workshop P. Barnes, T. Barnes, J.Bjorken, S. Capstick, L.Cardman, C. Carlson. S.Chandrasekharan, J.Peng, F.Close, T.Cohen, K.Dejager, J.Domingo, S.Dytman, A.Dzierba, R.Edwards, R.Ent, G.Garvey, R.Holt, D.Isenhower, N.Isgur,R.Jaffe, S.Jeschonnek, X.Ji, E.Kinney, F.Lee, M.Leitch, N.Makins, A.Manohar, J.McCelland, L.McLerran, W.Melnitchouk, M.Mestayer, C.Meyer, C. Michael, R.Milner, C.Morningstar, J.Moss, B.Nefkens, A.Radyushkin, D.Richards, E.Shuryak, M.Strikman, E.Swanson, A.Szczepaniac, H.Thacker, B.Tippens, F.Wilczek Key Issues in Hadron Physics QCD 1 2.5 Morning Summary Talk Discussion Afternoon Organization Summary Talk Discussion Key Issues in Hadron Physics QCD Strong interaction physics poses a wealth of fundamental questions with profound significance for our understanding of Nature and the structure of the matter of which we and our universe are composed. Answering these questions lies at the heart of contemporary nuclear science and will deeply impact particle physics, astrophysics, and cosmology. Key Issues in Hadron Physics QCD The main goals of hadronic physics are to determine the effective degrees of freedom which describe hadronic phenomena at all scales, to establish the connection of these degrees of freedom to the parameters of Quantum Chromodynamics, and to employ the subsequent understanding to describe a wide array of phenomena ranging from nuclear physics to early universe cosmology. Key Issues in Hadron Physics QCD Establish the place of QCD in the Standard Model. Understand the origin and dynamics of confinement and chiral symmetry breaking Understand the structure of the QCD vacuum and its topological characteristics How do quarks and gluons evolve into hadrons? Establish the link between the parton picture in the infinite momentum frame with the structure of hadrons in the rest frame. Construct quantitatively reliable models of QCD Establish rigorous connections with nuclear physics, electroweak physics, astrophysics and condensed matter physics. What is the role of quarks and gluons in nuclei and extreme matter? Key Issues in Hadron Physics QCD Science Highlighted in New Department of Energy Strategic Plan 2.) "Develop a quantitative understanding of how quarks and gluons provide the binding and spin of the nucleon based on quantum chromodynamics, further clarifying the theory of strong interaction as a component of the Standard Model," Key Issues in Hadron Physics QCD The QCD Lagrangian : LQCD m d mu L , ms m Z The parameters: QCD s , , m d mu What are the degrees of freedom? What are the mechanisms responsible for confinement? for chiral symmetry breaking? for the UA(1) symmetry breaking? Reality Experiment Models Physical Insights Numerical Precision LGT Key Issues in Hadron Physics QCD Quark and Gluon Structure of Hadronic Matter from Hard Scattering What is the structure of hadrons in terms of their quark and gluon constituents? How do quarks and gluons evolve into hadrons via the dynamics of confinement? What is the role of quarks and gluons in the structure of nuclei? How can nuceli be used to study matter under extreme conditions? SN quarks carry 30%, L?, polarized glue DG strange quark -10% PN gluons? strange quarks about 0% At large x, expect all the spin on struck quark 1st generation lattice of spin and form factors have good agreement. Can compute the lowest order moments Do other hadrons (mesons, hyperons) have the same structure? Key Issues in Hadron Physics QCD Quark and Gluon Structure of Hadronic Matter from Hard Map out the quark and gluon structure of the nucleon Scattering { e' e x Deep inelastic scattering Q2 qv x p q v x q q e g* s x s x 0 G x,Q 2 2 G x,Q s0.1 Drell-Yan Directly sensitive to antiquark distributions l+ u d0 l- e' Deep exclusive scattering g,p,h,... p valence quarks, sea quarks, gluons, virtual mesons, tranversity, skewed parton distributions p' Key Issues in Hadron Physics H x, , t E x, , t x , , t H E x ,, t u d ? Connected to GM(t), GE(t) } Connected to Lq QCD Quark and Gluon Structure of Hadronic Matter from Hard Scattering Understand the role of quarks and gluons in nuclei: Nuclear Binding, Quarks and gluons in nuclear medium We know that structure functions change in the nucleus Can we see x>1 effects? Are the nuclear enhancements of valence quarks, sea quarks or gluons? Would these give us information on which exchanges are important for binding at various scales Key Issues in Hadron Physics QCD Quark and Gluon Structure of Hadronic Matter from Hard Scattering Understand how a quark becomes a hadron Hadronization, Exlcusive Processes Still a very open question, done via Lund but no spin effects are included in fragmentation. How is spin transferred to the hadronic daughter particle. qq How are pairs formed from the vacuum? 3P0 model? dq(x) transversity is related to the T-odd frag.fcn. H 1 z Semi-inclusive DIS can tag quark flavour. Fragmentation is what happened in the Big Bang Key Issues in Hadron Physics QCD Quark and Gluon Structure of Matter from Spectroscopy Quark Model of Hadrons Rest frame structure of hadrons - "dressed quarks" q q What are the fundamental degrees of freedom? Where is the glue? What role does glue play? What can be excited? Key Issues in Hadron Physics QCD Quark and Gluon Structure of Matter from Spectroscopy Lattice Calculations Quenched Glueball Spectrum N* up to spin 5/2 Exotic Spectrum Models Quark Models .. work too well Instantons Fluxtubes We are on the verge of seeing gluonic excitations Mapping out the spectrum will tell us how glue is manifested in the real world Opportunity exists with photon beams Much new information will be emerging on Baryons K-beams could provide new important information Key Issues in Hadron Physics Data Scalar Meson Sector f0(1370) f0(1500) f0(1710) Mesons with Exotic Quantum Numbers 1-+ at 1.4 and 1.6 Decays of mesons. Missing states photocouplings Q2 Dependence Decays Parity Doubling UA(1)? Y* States X*States High Quality High Statistics Significantly change our understanding. QCD Quark and Gluon Structure of Matter from Spectroscopy c c b b Hybrids Heavy-light systems B D Hybrids Gift of Nature? Final State Interactions CP Studies: B Decays D, DS Decays Windows of opportunity in gg physics and y Decays Key Issues in Hadron Physics QCD Models - Physical Intuition Understand Hadronic data in terms of the appropriate degrees of freedom Q2 << 1 Structure Q2 ~ 1 Substructure Q2 >> 1 Partonic Regime Key Issues in Hadron Physics } Connect to the QCD Vacuum QCD Models - Physical Intuition Structure: Substructure Key Issues in Hadron Physics Constituent Quarks potential models vs flux tubes vs bags. Properties derivable on the lattice Easiest comparison to experiment low energy hadron-hadron interactions Decays - why does 3P0 work Degrees of freedom in terms of fundamental QCD fields connect to the constituent quarks. Constituent Quarks -- evolve from Dyn.Chiral Sym Break. Topological configurations: Instantons -- break UA(1) Sym monopoles, center vortices ... Flux tubes -- confinement. QCD Models - Physical Intuition Partonic Regime: What is the connection to Q2=1 How are inclusive observables (structure functions) related to exclusive observables (form factors)? What are the primordial structure functions as input to QCD evolution? Explanation for observed sea quark isospin and spin structure Bloom Gilman Duality Key Issues in Hadron Physics QCD Hadron Structure: Complementary Perspectives Snapshots in quark and glue Quark Model Picture Deep inelastic scattering Hadron Spectroscopy Charge Radius Magnetic Moment What are the relevant degrees of freedom? Relationship? Caculable on the Lattice Pictures with dressed quarks Key Issues in Hadron Physics quarks and glue in the infinite momentum frame Structure functions measure quarks and gluons releated directly to the QCD Lagrangian Low moments calculable QCD QCD in the wider world QCD is the essential ingredient of the standard model that is not yet under quantitative control Astrophysics p ms s s p neutralino "dark matter" High Energy Physics B KK mnm p Extreme Conditions Measures b+g Mixing vs fundamental parameters The grand challenge QCD in the early universe QGP Low x vs High energy n scattering High densities Condensed Matter Physics Key Issues in Hadron Physics neutron stars/supernovaes Insights and techniques QCD CONCLUSIONS Accelerators Detectors Computers Lattice Algorithms Data Lattice The Puzzles are old Models Key Issues in Hadron Physics At the threshold of significant progress in resolving the issues QCD