abstract

Using the Blast-Wave parameterized model in THERMINATOR 2, we study the effect of the radial flow and resonance decay on the transverse momentum dependence of HBT parameters for Au+Au central collisions at the RHIC energy \(\sqrt {s_{NN}}=200~\rm {GeV}\). The results indicate that the radial flow directly affects the space-momentum correlations and the dependence of the transverse HBT radii on transverse momentum. The rise of \(\alpha \) with increasing \(v_{\rm T}\) for \(R_{\rm {out}}\) is faster than that for \(R_{\rm {side}}\) which suggests that \(R_{\rm {out}}\) is more susceptible to the radial flow. The pions decayed from resonance increase the HBT radii and strengthen the negative dependence of the radii on transverse momentum.

abstract

The transverse momentum spectra of various hadrons at different centralities at the RHIC energy of \(\sqrt {s_{NN}}=200\) GeV are studied. The study is based on a unified statistical thermal freeze-out model which incorporates the longitudinal as well as transverse boosts. The model also incorporates the dependence of the baryonic chemical potential on rapidity of the forward fireballs distributed along the longitudinal axis. The transverse momentum spectra have been found to be in close agreement with the available RHIC experimental data at all centralities. The kinetic freeze-out parameters are extracted by comparing our model results with the experimental data using the method of minimization of \(\chi ^{2}\)/DOF. The extracted parameters indicate that the freeze-out temperature increases with decreasing centrality, while the collective flow velocity increases with the increase in centrality of the colliding system. The work is studied with the inclusion of all heavier resonance decay contributions.

abstract

The cross section and reaction rate of the proton and alpha capture reactions on \(^{102}\)Pd, \(^{120}\)Te, \(^{124,126}\)Xe, and \(^{130,132}\)Ba have been calculated through TALYS in Hauser–Feshbach formalism using relativistic mean field densities. Nuclear structure studies have been also carried out for the nuclei under consideration. Results obtained in the present work for nuclear structure as well as nuclear reaction are in a fair agreement with the available experimental results.

abstract

We study the contribution of the torsion-descendent four-fermion contact interaction to the decay width of a neutral (pseudo)scalar field into a fermion pair. This new interaction comes from the existence of gravitational torsion in models with extra dimensions. Additionally, we exemplify the formalism by studying two cases: first, the variation of the considered branching ratio of the Higgs in the context of the Standard Model, and second the proper variations of the scalar and pseudoscalar fields of the type II-1 two-Higgs doublets model.

abstract

This research addresses the chaotic synchronization of an uncertain chaotic system as the master system with multiple chaotic systems as slave systems, simultaneously. Adaptive control and parameter estimation laws based on the hybrid modified projective synchronization (HMPS) method are derived to synchronize the states of a master chaotic system with a proportional rate of their corresponding states from multi-slave chaotic systems. The feasibility and stability of the proposed scheme are analytically proved by means of the Lyapunov stability theorem. Furthermore, the validity of the proposed HMPS method and the theoretical discussions are verified by numerical simulations. The simulation results confirm the effectiveness of the proposed method.

abstract

This paper incorporates a micro-level decision-making paradigm along with a social interaction model (bounded confidence) in the presence of influences (zealots). Every agent in the society represents a node in a Barabási–Albert network and is given a decision-making ability (to choose from a fixed set of states). The decision making is based on maximization of estimated accumulated rewards gained as a result of an individual’s own sequence of choices in the presence of different probabilities of external events. The effects of interactions, and events on the final distribution of decision states are studied with and without the presence of influences. Bounded confidence model parameters (the distance parameter and the convergence parameter) are used to study the final distribution of states, and the time the society needs to reach its equilibrium (convergence time). Finally, effects of network topology on the final distribution of states and convergence time are presented.