title: Isospin tracing: A probe of nonequilibrium in central heavy-Ion collisions
abstract: Four different combinations of 9644Ru and 9640Zr nuclei, both as projectile and target, were investigated at the same bombarding energy of 400A MeV using a 4pi detector. The degree of isospin mixing between projectile and target nucleons is mapped across a large portion of the phase space using two different isospin-tracer observables, the number of measured protons and the tritium to 3He yield ratio. The experimental results show that the global equilibrium is not reached even in the most central collisions. Quantitative measures of stopping and mixing are extracted from the data. They are found to exhibit a quite strong sensitivity to the in-medium ( n,n) cross section used in microscopic transport calculations.
authors.affiliation: Institut de Recherches Subatomiques, IN2P3-CNRS, Universite Louis Pasteur, Strasbourg, France.
authors.initials: F
authors.lastname: Rami
authors.initials: Y
authors.lastname: Leifels
authors.lastname: de Schauenburg B
authors.initials: A
authors.lastname: Gobbi
authors.initials: B
authors.lastname: Hong
authors.initials: JP
authors.lastname: Alard
authors.initials: A
authors.lastname: Andronic
authors.initials: R
authors.lastname: Averbeck
authors.initials: V
authors.lastname: Barret
authors.initials: Z
authors.lastname: Basrak
authors.initials: N
authors.lastname: Bastid
authors.initials: I
authors.lastname: Belyaev
authors.initials: A
authors.lastname: Bendarag
authors.initials: G
authors.lastname: Berek
authors.initials: R
authors.lastname: Caplar
authors.initials: N
authors.lastname: Cindro
authors.initials: P
authors.lastname: Crochet
authors.initials: A
authors.lastname: Devismes
authors.initials: P
authors.lastname: Dupieux
authors.initials: M
authors.lastname: Dzelalija
authors.initials: M
authors.lastname: Eskef
authors.initials: C
authors.lastname: Finck
authors.initials: Z
authors.lastname: Fodor
authors.initials: H
authors.lastname: Folger
authors.initials: L
authors.lastname: Fraysse
authors.initials: A
authors.lastname: Genoux-Lubain