Charged and neutral hyperonic effects on the driplines

Abstract

Modification of neutron and proton driplines by the capture of strange hyperon(s) by normal nuclei has been investigated. A generalised mass formula (BWMH) based on the strangeness dependent extended liquid drop model is used to calculate the binding energy of normal nuclei as well as strange hypernuclei. The neutron (Sn) and proton (Sp) separation energies of all hypernuclei with neutral hyperons Lambda, double Lambda or charged hyperons Cascade(-), Theta(+) inside are calculated using BWMH mass formula. The normal neutron and proton driplines get modified due to the addition of the hyperon(s)(Lambda, double Lambda, Cascade(-), Theta(+) etc.) to the core of normal nuclei. The hypernuclei containing the charged hyperon(s) like those with neutral hyperon(s) have similar nucleon separation energies like core nuclei if proton number instead of net charge is used in the symmetry term. Due to the effect of opposite charges present in Theta(+) and Cascade(-), hyperons their corresponding driplines get separated from each other. All the hyperons modify mean field potential due to strong hyperon-nucleon coupling. Addition of a single charged hyperon in normal nuclei affects the entire proton drip line more prominently than that by neutral hyperon. The neutral hyperonic effect on proton dripline is significant for lighter nuclei than for heavier ones whereas both the charged as well as neutral hyperons affect almost the entire neutron dripline.