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Utrecht University. Models for CONFINEMENT. Gerard ’t Hooft Spinoza Institute Utrecht, the Netherlands. Contents. First part: Absolute Quark Confinement in lattice QCD Second part: Absolute Quark Confinement as a topological Phenomenon Third part:
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Utrecht University Models for CONFINEMENT Gerard ’t Hooft Spinoza Institute Utrecht, the Netherlands
Contents First part: Absolute Quark Confinement in lattice QCD Second part: Absolute Quark Confinement as a topological Phenomenon Third part: The Gluon Chain Model (Greensite, Thorn) Try to do it better: compare Renormalization Procedure (infinite) Infrared Renormalization The renormalized Coulomb potential (in radiation gauge) Fourth part: Gauge invariant procedure Renormalized effective actions: an exercise in Legendre Transformations
What kinds of forces were holding them together?
The hadronic particles … Antiproton Proton Lambda Pi-plus Pi-zero
Using the expansion In the expansion, only terms where the energy increases linearly with inter- quark distance survive ! Part 1: Lattice QCD (K. Wilson, London, 1974)
S N Part 2: Magnetic Confinement In case of spontaneous "breakdown" of H.B. Nielsen and P. Olesen, 1970.
_ + Color Magnetic Super Conductivity S N Electric Super Conductor Magnetic Super Conductor
The Magnetic Monopole G. ’t H (1974), A.M. Polyakov (1974) • Mandelstam (1975), • G. ’t H (1976)
Ansatz for the "Wave Function": Use variational principle, minimize Part 3:The gluon chain approach Anti- quark quark J. Greensite and C.B. Thorn hep-ph/0112326 [ ? ] then, improve Ansatz
This can be done better The gluon chain model gives reasonable – looking "stringlike“ structures for the mesons … but confinement is not built in … The chainlike states will surely not form a complete set of states. UNITARITY ? Describe a "modified" perturbative approach, where unitarity is guaranteed Infinite infrared renormalization
Compare UV renormalization Lowest order Combine this with the higher order terms
now generates a potential Vbetween charges obeying Perturbative Confinement
in space: Let V be a confining potential, typically: then
should be treated exactly like a renormalization counter term. Compare our procedures in the renormalization group: the coefficients (here: ) must be adjusted in such a way that the higher order correction terms, together with the contributions from , should be as insignificant as possible. At lowest order, we should start with a Fock space of Eigen states of particles bound by the potential V . They are confined from the very beginning:
Stationary case: Part 4: A Classically Confining Theory: U ( D ) can become any monotonically increasing function of D
D Q -Q
1 Legendre Transformations:
Quantum Chromodynamics is an extremely accurate theory. At short distances, the forces become weak, so that perturbative treatment there is possible. Calculating the QCD contributions to high-energy scattering processes has become routine. Interesting and important problems remain: - find a quark-gluon plasma - find more accurately converging calculation procedures ... Utrecht University
Further References: Erice: hep-th / 9812204 Montpellier Proceedings (2002) Nucl. Phys. B 138 (1978) 1 Nucl. Phys. B 153 (1979) 141 Nucl. Phys. B 190 (1981) 455 Acta Phys. Austriaca Suppl. XXII (1980) 531 Physics Reports 142 (1986) #6, 357 hep-th / 9903189 The End