The vacuum stability lower bound on the mass of the Higgs boson is numerically investigated in an SU(2)L ⊗ SU(2)R symmetric Yukawa model, which describes two heavy degenerate fermion doublets in the limit of vanishing gauge couplings. Good agreement with perturbation theory is found, although the couplings are strong. The upper bound on the fermion mass and renormalized Yukawa coupling is also ...

(2+1)-dimensional Georgi-Glashow model, else called the Polyakov model, is explored at nonzero temperatures and in the regime when the Higgs boson is not infinitely heavy. The finiteness of the Higgs-boson mass leads to the appearance of the upper bound on the parameter of the weak-coupling approximation, necessary to maintain the stochasticity of the Higgs vacuum. The modification of the finit...

of the triple fission of 252Cf . Further on, investigations on hypernuclei and the possible production of antimatter-clusters in heavy ion collisions are reported. Various versions of the meson field theory serve as effective field theories as the basis of modern nuclear structure and suggest structure in the vacuum which might be important for the production of hyperand antimatter. A perspecti...

The recent suggestion of a vanishing flavor-singlet axial charge of nucleon due to a nontrivial vacuum structure is further amplified. A perturbative QCD discussion, applicable for the heavy quark contributions, relates it to the physics of the decoupling theorem. It is also shown that g A ≃ 0 leads to a negative η-meson-quark coupling, which has been found to be compatible with the chiral quar...

Lattice QCD results relevant to heavy quark physics are reviewed. In particular new results will be shown that, for the first time, include dynamical quarks in the QCD vacuum which are close enough to being realistic to allow accurate extrapolation to the physical point. Agreement with experiment is found for a wide range of spectral quantities and the implications of this for hadronic matrix e...

An ion beam has quite different vacuum requirements in different sections of an accelerator. Behind a stripper gas or after interaction with a gas target the vacuum conditions are poor, whereas in an accelerator module or especially in a storage ring the residual gas pressure has to be orders of magnitude better. As a new device to allow an ion beam to enter sections of different pressure we in...

An overview of some issues discussed is given, including the following ones: (i) the mechanism of confinement, (ii) the structure of the string, (iii) nonperturbative glue in vacuum and hadrons, and (v) quark-hadron duality. In doing so I try to indicate issues important for JLab. Finally I discuss another issue debated during this conference, namely (vi) whether one can use some common effecti...

We use the SU(3) x SU(2) x U(1) renormalization group equations to constrain fermion masses and charged-scalar couplings in two-Higgs grand unified theories. We find upper bounds on the sum of all quark (or lepton) masses and show that the Cabibbo mixings of heavy quarks tend to be small. We bound the vacuum expectation values of the Higgs fields, and use these limits to place strong restrictio...

The theory of direct electron-positron pair production in the collision of heavy ions i s formulated in the framework of the quasimolecular model. The pair production process acquires a collective nature for (Z1 +Z,)cu; 1 and can be understood a s the shakeoff of the strong vacuum polarization cloud formed in the quasimolecule. The total Cross section is, e .g., 76 l b for Pb + Pb at Coulomb ba...

New results at four-loop order in perturbative QCD for the first two Taylor coefficients of the heavy quark vacuum polarization function are presented. They can be used to perform a precise determination of the charmand bottom-quark mass. Implications for the value of the quark masses are briefly discussed. PACS. 12.38.Bx Perturbative calculations – 12.38.-t Quantum chromodynamics – 11.55.Fv Di...