Residual correlations between decay products of $\pi^0\pi^0$ and $p\Sigma^0$ systems

TL;DR

This paper discusses residual correlations between decay products like photons and baryons, proposing their use to extract information on particle interactions and source characteristics in high-energy physics.

Contribution

It introduces a new approach to analyze residual correlations in decay products, linking them to parent particle interactions and source dimensions, based on a detailed theoretical model.

Findings

Residual correlations in photon and baryon systems are predicted.

The shape and intensity of correlations depend on scattering parameters and source size.

Neglecting residual correlations can bias source size estimates.

Abstract

Residual correlations between decay products due to a combination of both correlations between parents at small relative velocities and small decay momenta are discussed. Residual correlations between photons from pion decays are considered as a new possible source of information on direct photon fraction. Residual correlations in $p\gamma$ and $p\Lambda$ systems due to $p\Sigma^0$ interaction in final state are predicted based on the $p\Sigma^0$ low energy scattering parameters deduced from the spin-flavour SU$_6$ model by Fujiwara et al. including effective meson exchange potentials and explicit flavour symmetry breaking to reproduce the properties of the two-nucleon system and the low-energy hyperon-nucleon cross section data. The $p\gamma_{\Sigma^0}$ residual correlation is concentrated at $k^* \approx 70$ Mev/$c$ and its shape and intensity appears to be sensitive to the scattering parameters and space-time dimensions of the source. The $p\Lambda_{\Sigma^0}$ residual correlation recovers the negative parent $p\Sigma^0$ correlation for $k^* > 70$ Mev/$c$. The neglect of this negative residual correlation would lead to the underestimation of the parent $p\Lambda$ correlation effect and to an overestimation of the source size.