Search

We calculate the cross sections for the inclusive production in the fragmentation region of $\Theta^+(1540)$ and $\Lambda(1520)$ in $pp$ collisions and $\Lambda(1520)$ in $\Sigma p$ collisions at high energy using the $K$- and $\pi$-meson exchange diagrams, respectively. The contributions of these diagrams survive at asymptotically large energies and are energy independent in this region up to logarithmic and power corrections. We find that inclusive $\Theta^+(1540)$ production should be at the level of 1 $\mu\mathrm{b}\times\Gamma_{\Theta KN}/ 1$ MeV. The ratio of the $\Theta^+(1540)$ over the $\Lambda(1520)$ yields is found to be $\sim 1%$. The fraction of $\Lambda(1520)$ yields in $\Sigma p$ and $pp$ collisions is $\sim 2.7$ that quantitatively agrees with the preliminary result of the Fermilab fixed target experiment E781., Comment: 5 pages, 5 figures, 1 table; RevTeX4

We investigate numerically 10 - dimensional Euclidean quantum gravity (with discretized Einstein - Hilbert action) in the framework of the dynamical triangulation approach. For the considered values of the gravitational coupling we observed two phases, the behavior of which is found to be similar to that of the crumpled and elongated phases of 3, 4 and 5 dimensional models. Surprisingly, (for the observed lattice sizes) the natural state of the 10 D system (when the Einstein - Hilbert action is turned off) is found to resemble branched polymer while in the low dimensional systems the natural state belongs to the crumpled phase., accepted for the publication in Phys.Lett.B

We found an additional symmetry hidden in the fermion and Higgs sectors of the Standard Model. It is connected to the centers of the SU(3) and SU(2) subgroups of the gauge group. A lattice regularization of the whole Standard Model is constructed that possesses this symmetry., Comment: 6 pages, no figures. Shortened version

We consider the SU(2) lattice gauge model and investigate numerically the continuum limit of the simple center vortices which are singular configurations of the gauge fields. We found that the vortices remain alive in the continuum theory. Also we investigate the Creutz ratio and found that for all $\beta$ it vanishes for those field configurations which do not contain the simple center vortices inside the considered Wilson loop. It leads us to the conclusion that these singular field configurations play a real role in the continuum theory., Comment: 10 pages LaTeX, 2 .eps figures

New topological objects, which we call center monopoles, naturally arise in the Maximal Center Projection of SU(3) gluodynamics. The condensate of the center monopoles is the order parameter of the theory., Comment: 4 pages revtex, 3 figures

We have investigated by Monte Carlo simulation a recently proposed lattice regularization of gauge theories where the gauge fields are noncompact but gauge-invariance is exact. We have found a nonvanishing value of the string tension.

We have studied a formulation of gauge theories on a lattice by means of gauge-invariant variables by a Monte Carlo simulation. The gauge-invariant variables used appear in a polar representation for the gauge field and they have been defined on the lattice both in compact and noncompact form. We have found a vanishing value of the string tension.

We investigate properties of soliton solutions in two space and one time dimension of two confining field theories, in particular rotation and Regge trajectories. Numerically we study the collision process in a two-soliton collision.

For nucleons interacting via formation of the quark compound bag the resulting potential is written in a general form. Explicit examples of potentials are constructed in the 1 S 0 , 3 S 1 and 3 S 1 - 3 D 1 states fitted to the experimental data at T L ⪅ 1 GeV. As an outcome the QCB energy levels (dibaryons) and NN admixture in QCB are obtained in good agreement with theoretical predictions.

An additional $Z_6$ symmetry hidden in the fermion and Higgs sectors of the Standard Model has been found recently\cite{BVZ2003}. A lattice regularization of the Standard Model was constructed that possesses this symmetry. In \cite{BVZ2004} we have reported our results on the numerical simulation of the Electroweak sector of the model. In this paper we report our results on the numerical simulation of the full ($SU(3)\otimes SU(2) \otimes U(1)$) model. The phase diagram of the model has been investigated using static quark and lepton potentials. Various types of monopoles have been constructed. Their densities appear to be sensitive to the phase transition lines. Differences between the realizations of the Standard Model which do or do not possess the mentioned $Z_6$ symmetry, are discussed., Latex, 14 pages