From Quarks and Gluons to Quantum Gravity

The following sections are included:

• PREFACE

• CONTENTS

The following sections are included:

• Introduction
  • Why the lattice?
  • Why SU(N → ∞)?

• Lattice calculations
  • Overview
  • From lattice to continuum
  • Example : the SU(3) mass spectrum
  • Glueballs: an aside about the 'real world'

• The physics of SU(N) gauge theories
  • The confining string and its tension
  • The mass spectrum
  • k-strings
  • Some other results

• Some final remarks

• References

These lectures start with a brief overview of salient features of the critical region of hot QCD. The main emphasis is on the accurate description of static plasma observables by the well-known hierarchy of reduced actions combined with 3D simulations above T ∼ 2T_c. A striking pattern emerges, put in perspective by completing the quasi-particle picture.

These lectures cover applications of the semiclassical theory to QCD. We start with tunneling through the topological barrier described by the instantons, and review their multiple applications in QCD. The interacting instanton liquid model describes the ensemble of instantons, in its multiple phases. The QCD vacuum happens to be a disordered "liquid", which breaks spontaneously chiral symmetry. The high-T phase is kind of a "molecular gas" which does not break any symmetries. High density phase is a color superconductor: here instantons form chains or diquarks. As recent applications we briefly discuss correlation functions and pion and nucleon form-factors. We discuss in some detail also the fate of instantons at large number of colors N_c. The second set of topics are applications of the semi-classical theory of high energy collisions: instead of tunneling through the barrier one has in this case excitation from under the barrier to it. These methods were recently applied to the old problem of soft Pomeron, and especially for explanations of puzzling behaviors of heavy ion collisions observed recently at Relativistic Heavy Ion Collider in Brookhaven.

The following sections are included:

• Confinement: an overview
  • Some preliminary questions
  • Confinement in pure Yang-Mills

• Confinement of Magnetic Flux

• Duality, Sources and Fluxes
  • Electric Sources and Fluxes
  • Magnetic Sources and Fluxes
  • Conclusion

• Duality and Confinement
  • Duality and QCD
  • Seiberg duality for SO(N) gauge theories
  • Confinement or not?
  • Spinor sources from the dual point of view
  • Conclusion

• References

Evidence in favor of supersymmetric grand unification including that based on the observed family multiplet-structure, gauge coupling unification, neutrino oscillations, baryogenesis, and certain intriguing features of quark-lepton masses and mixings is noted. It is argued that attempts to understand (a) the tiny neutrino masses (especially Δm²(ν₂ – ν₃)), (b) the baryon asymmetry of the universe (which seems to need leptogenesis), and (c) the observed features of fermion masses such as the ratio m_b/m_τ, the smallness of V_cb and the maximality of , seem to select out the route to higher unification based on an effective string-unified G(224) = SU(2)_L × SU(2)_R × SU(4)^c or SO(10)-symmetry, operative in 4D, as opposed to other alternatives.

A predictive framework based on an effective SO(10) or G(224) symmetry possessing supersymmetry is presented that successfully describes the masses and mixings of all fermions including neutrinos. It also accounts for the observed baryon asymmetry of the universe by utilizing the process of leptogenesis, which is natural to this framework. It is argued that a conservative upper limit on the proton lifetime within this SO(10)/G(224)-framework, which is so far most successful, is given by years. This in turn strongly suggests that an improvement in the current sensitivity by a factor of five to ten (compared to SuperK) ought to reveal proton decay. Implications of this prediction for the next-generation nucleon decay and neutrino-detector are noted.

No abstract received.

A good understanding of Perturbative Quantum Gravity is essential for anyone who wishes to proceed towards any kind of non-perturbative approach. This lecture is a brief resumé of the main features of the perturbative regime.

In spite of the tremendous progress achieved in establishing the validity of the Standard Model of weak, electromagnetic and strong interactions, there are still many mysteries. In particular, the structure of the proton, whose mass is in 98% generated by strong interactions [1], cannot be calculated from first principles and has to be investigated experimentally. In this lecture, the present status of our knowledge on the parton decomposition of the proton is shortly summarized.

For the first time, nucleus-nucleus collisions at RHIC occur at sufficiently high that the yield of jets from hard and semi-hard scattering of partons may be used as an effective probe of the hot, dense matter which is produced. This has led to several intriguing observations in AuAu collisions at and 200 GeV…

Experiments in underground laboratories searching for rare phenomena in the low background environment they provide can give information on energy scales that cannot be reached by present or future accelerators. Already and for the first time experiments on neutrino produced by natural sources have given evidence for physics beyond the Standard Model. We are now planning the next phase of the new neutrino physics both with natural and artificial neutrino sources. The search for cold dark matter is another avenue to new physics that must be followed.

After an introduction on the new neutrino physics I'll report on the results obtained at the INFN Gran Sasso National Laboratory and on the perspectives of its future program.

No abstract received.

No abstract received.

This article describes preliminary results of a search for neutral Higgs bosons within a CP violating Minimal Supersymmetric Model (MSSM). The results are based on the complete dataset collected with the OPAL detector at LEP with centre-of-mass energies ranging from to 209 GeV. The searches for the Standard Model Higgs boson and for the neutral Higgs bosons in the CP-conserving MSSM are re-interpreted and extended. The dominant production mechanisms, Higgsstrahlung and Higgs boson pair production, are considered for the lightest (H₁) and the next-to-lightest (H₂) neutral Higgs mass eigenstates. No significant excess over the expected SM background was observed. Regions in the parameter space of a CP violating benchmark scenario are excluded.

It is shown that the implementation of the Large–N_c approximation helps to get insight into the structure of, in principle, any QCD-like theory. As an example, we will compute the NLO corrections to L₁₀ in the chiral limit with a Lagrangian with Resonances.

Yang-Mills theories undergo a deconfining phase transition at a critical temperature. In lattice calculations the temporal Wilson loop and. Z₃ order parameter show above this temperature a behavior typical of deconfinement. A quantity of interest in the study of this transition is the gluon propagator and its evolution with temperature. This contribution describes the current status of an investigation of the finite temperature gluon propagator in Landau gauge. It analyzes the high temperature case. The resulting equations are compared to the corresponding ones of three-dimensional Yang-Mills theory. Under certain assumptions it is found that a kind of spatial "confinement" is still present, even at very high temperatures.

The HERMES collaboration has measured double spin asymmetries using polarized deep inelastic scattering. The spin structure functions g₁ of the proton, the neutron, and the deuteron calculated from inclusive asymmetries are in agreement with world data. Semi-inclusive asymmetries of hadrons were measured from proton and deuteron targets with high precision. Asymmetries of pions from the proton and of pions and kaons from the deuteron were measured for the first time. Quark polarizations of the u, , d, , flavours were extracted from the inclusive and semi-inclusive spin asymmetries in a LO analysis. The polarizations of the up and the down quarks were determined with good precision to be positive and negative, respectively. The polarization of the sea quarks is consistent with zero.

The following sections are included:

• DIPLOMAS

• AWARDS

• PARTICIPANTS