abstract

The classical \(X\)-\(Y\) model on a one-dimensional lattice is considered. The \(X\)-\(Y\) model is investigated as a two-component classical spin. Dynamics of the system is determined by the Hamilton equations for the spin field. By means of the zero curvature representation the integrability in the kinematic sense was proved.

abstract

We present a new realisation of the Sp(2,\(R\)) algebra and show its connections with a quantum anharmonic oscillator. This new realisation admits only one unitary irreducible representation, comprising states with both even and odd parities. Coherent states for this realisation exhibit squeezing, though weaker than the standard squeezed vacuum states.

abstract

The structure and form of the dominant contribution of higher order corrections for a hadronic process in the next-to-leading order with respect to the running coupling a, are shown explicitly. We demonstrate that this contribution comes from the soft and/or collinear configuration of the particles in the final or initial state. We give the origin of various terms of this contribution and a prescription to derive them.

abstract

We argue, using the Lund Monte Carlo model, that the increase in mean transverse momentum \(\left \lt p_{\rm T}\right \gt \) with the number of charged particles \(n_{\rm ch}\), recently observed in \(e^+e^-\) annihilations at LEP, has a significant contribution from the production of strange particles and (anti)baryons. The correlations of \(\left \lt p_{\rm T}\right \gt \) with \(n_{\rm ch}\) for kaons, protons and hyperons are much stronger than for pions. The pattern of relative strengths of the correlations for these particles is similar to that observed in high energy \(p \bar p\) collisions. The comparison of the data for the two reactions could provide a new insight into the dynamical origin of these correlations in hadronic interactions.

abstract

In the framework of the model of algebraically composite particles, a new form of the standard-model coupling to gauge fields is introduced, where the “visible” chirality is always included, but via the total chirality comprising two factors: the “visible” chirality and total “hidden” chirality. For leptons and quarks the latter factor assumes its eigenvalue +1, giving the usual standard-model coupling. In the case of the new coupling there exist, beside three and only three replicas of leptons and quarks, two and only two replicas of Yukawa bosons of all colors and weak flavors defined by the standard-model coupling to gauge bosons.

abstract

The systematic study of the transverse momentum distributions of the multicharged fragments shows that the presence of high \(p_{\rm t}\) tail distorts the distributions of fragments and the fragmentation model describes the features of these distributions only for \(p_{\rm t} \leq 500\) MeV/\(c\). Values of Nuclear Fermi momentum obtained in the present experiment are in agreement with that of electron scattering experiment and the excitation energy observed is the order of binding energy per nucleon. Analysis of diffraction dissociation (\(^{12}\)C \(\to 3 ^4\)He) events shows that the percentage of such type of events is 2.0 of the total inelastic collisions and such type of reaction goes through an intermediate \(^8\)Be state.

abstract

The lattice in percolative simulations of nuclear fragmentation is shown to have a notable effect on the final result from a nucleon clustering, in the case when the total energy is constrained to be conserved.