A study of genuine pion correlations and fluctuations in relativistic nucleus–nucleus collisions

In this study, we have performed a detailed analysis of genuine pion correlations and fluctuations in terms of the normalized factorial comulant moments of second and third orders, [Formula: see text] and [Formula: see text], in case of [Formula: see text]O–AgBr interactions at [Formula: see text][Formula: see text]A and [Formula: see text][Formula: see text]A GeV/c. The experimental results are compared with the predictions of AMPT and UrQMD model simulated events. The UrQMD model reproduces the trends in experimental results but the strength of correlation is much smaller. However, the AMPT model does not also replicate all features of the experimental data. The genuine two-particle and three-particle correlations are found to become weaker with the increase in momentum of the projectile nucleus.

Pair-correlation ansatz for the ground state of interacting bosons in an arbitrary one-dimensional potential

We derive and describe a very accurate variational scheme for the ground state of the system of a few ultra-cold bosons confined in one-dimensional traps of arbitrary shapes. It is based on assumption that all inter-particle correlations have two-body nature. By construction, the proposed ansatz is exact in the noninteracting limit, exactly encodes boundary conditions forced by contact interactions, and gives full control on accuracy in the limit of infinite repulsions. We show its efficiency in a whole range of intermediate interactions for different external potentials. Our results manifest that for generic non-parabolic potentials mutual correlations forced by interactions cannot be captured by distance-dependent functions.