abstract

We study the relation between the \(\psi (4160)\) and the \(Y(4260)\) within an unitarized effective Lagrangian approach. The \(Y(4260)\) arises as a manifestation of the \(\psi (4160)\), when a loop-driven decay of the type of \(\psi (4160)\to D_s^*\bar {D}_s^*\to J/\psi f_0(980)\) is enhanced by the proximity of the pole, corresponding to the \(\psi (4160)\), to the almost closed \(D_s^*\bar {D}_s^*\) decay channel. Other \(f_0\) resonances that may add a non-negligible contribution, by the same mechanism, are not included for simplicity, but they are not expected to change the main conclusion. Within this picture, the \(Y(4260)\) is not, therefore, an independent resonance, but rather a variation of the \(\psi (4160)\), which also explains why it is not seen in OZI-allowed decay channels in the experiment.

abstract

The production of light nuclei in relativistic heavy-ion collisions is well-described by both the thermal model, where light nuclei are in equilibrium with all other hadron species present in a fireball, and by the coalescence model, where light nuclei are formed due to final-state interactions after the fireball decays. A method to falsify one of the models is proposed. We suggest to measure a hadron–deuteron correlation function which carries information about the source of the deuterons and allows one to determine whether a deuteron is directly emitted from the fireball or if it is formed afterwards. The \(K^-\)–\(D\) and \(p\)–\(D\) correlation functions are computed to illustrate the statement.

abstract

The statistical theory of hot rotating nuclei (STHRN) method was implied to investigate the effect of shape transition in thermodynamical parameters for the isotopes of tellurium for (mass number) \(A = 114\), 120, 122, 124 and 126. The single particle energy levels and intrinsic spin were obtained by diagonalizing the triaxial Nilsson Hamiltonian for deformation parameter \( \epsilon = 0.0\) to \(0.6\) and shape parameter \(\gamma = -120^{\circ }\) to \(-180^{\circ }\). The calculated statistical parameters such as rotational frequency, spin cut-off parameter, separation energy and moment of inertia indicate a sudden change around the angular momentum \(M = 12\,\hbar \) at which the even–even isotopes of tellurium are found to change their shape from spherical to non-collective oblate. The results obtained show reasonable agreement with the experimental data and also with other theoretical models such as Interacting Boson Model-1 (IBM-1). The rotational frequency and moment of inertia values calculated from the STHRN method give reasonable agreement with the experimental data compared to IBM-1 model.

abstract

The Lévy walk model that takes into account a waiting of a walker between consecutive displacements is analysed. The motion is restricted to a finite region, bounded by two absorbing barriers, and quantities describing the escape from this region are determined. Simple expression for a mean first passage time is derived for a ballistic version of the Lévy walk. Two limits emerge from the model: of short waiting time, that corresponds to Lévy walks without rests, and long waiting time which exhibits properties of a Lévy flights model. The analytical results are compared with Monte Carlo trajectory simulations.

abstract

During the prevention and control of epidemics, both disease-related awareness diffusion and disease treatment require resources investment, so it is crucial to investigate the investment and allocation strategy of resources. Here, we propose an epidemiological model in the two-layer multiplex networks to study the interplay between disease and awareness under resource control. In this model, a part of the resources is used for disease treatment, and the other is used to facilitate the diffusion of awareness, with an adjustable parameter \(\alpha \) setting to allocate the resources. First, we establish the evolutionary equations for different states and obtain the epidemic threshold of disease based on the microscopic Markov chain approach. Then, we conduct numerical simulations and find that stronger heterogeneity of the two-layer networks results in smaller epidemic threshold. Intriguingly, we find that there are optimal allocation coefficients in different multiplex networks structures and sizes. Finally, we find that the optimal allocation coefficient decreases with the increase of the immune degree.