Residual correlations between decay products of $π^0π^0$ and $pΣ^0$ systems

Stavinskiy, A.; Mikhailov, K.; Erazmus, B.; Lednicky, R.

Residual correlations between decay products of $π^0π^0$ and $pΣ^0$ systems

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Description

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 $pγ$ and $pΛ$ systems due to $pΣ^0$ interaction in final state are predicted based on the $pΣ^0$ 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 $pγ_{Σ^0}$ 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 $pΛ_{Σ^0}$ residual correlation recovers the negative parent $pΣ^0$ correlation for $k^* > 70$ Mev/$c$. The neglect of this negative residual correlation would lead to the underestimation of the parent $pΛ$ correlation effect and to an overestimation of the source size.
10 pages, 5 figures