Experimental study of the isospin transport with 40,48 Ca+ 40,48 Ca reactions at 35 MeV/nucleon

Abstract

We investigate the isospin transport with 40,48 Ca+ 40,48 Ca reactions at 35 MeV/nucleon, measured with the coupling of the VAMOS high acceptance spectrometer and the INDRA charged particle multidetector. Using the quasi-projectile remnant measured with VAMOS and carefully selected light-charged-particles measured in coincidence with INDRA, a reconstruction method is applied to estimate the excited quasi-projectile (QP) on an event-by-event basis. The isospin diffusion is investigated using the isospin transport ratio with the asymmetry $\delta$ = (N -- Z)/A of the projectile as an isospin-sensitive observable and the total transverse energy of Z $\le$ 2 nuclei for experimental centrality sorting. The experimental isospin transport ratios present, for both the reconstructed QP and its remnant, a clear evolution towards isospin equilibration with increasing dissipation of the collision while the full equilibration is not reached. A smoother evolution with less discrepancies between the two mixed systems in the case of the reconstructed QP is also observed. The isospin migration is investigated using the neutron-to-proton ratio of the light-charged-clusters and the velocity of the QP remnant as a sorting parameter. More particularly, we focused on an angular region centered around the mid-rapidity of the reaction so as to characterize the low-density neck emissions. A systematic neutron-enrichment is observed and interpreted as a consequence of isospin migration, more particularly for the symmetric systems which present no isospin gradient between the projectile and the target. We also noticed that the ^{2}H and ^{4}He particles exhibit very close multiplicities independently of the sorting variable for the symmetric systems.

References in corpus (14)

• GW170817: Observation of Gravitational Waves from a Binary Neutron Star Inspiral
• PSR J0030+0451 Mass and Radius from NICER Data and Implications for the Properties of Neutron Star Matter
• Constraining Neutron-Star Matter with Microscopic and Macroscopic Collisions
• Results of the ASY-EOS experiment at GSI: The symmetry energy at suprasaturation density
• Measurement of the complete nuclide production and kinetic energies of the system 136Xe + hydrogen at 1 GeV per nucleon
• Dynamics of clusters and fragments in heavy-ion collisions
• Isospin Diffusion and Equilibration for Sn+Sn collisions at E/A=35 MeV
• Experimental investigation of the residues produced in the 136Xe+Pb and 124Xe+Pb fragmentation reactions at 1 A GeV
• Isospin diffusion in semi-peripheral ${}^{58}Ni$ + ${}^{197}Au$ collisions at intermediate energies (II): Dynamical simulations
• Neutron to proton ratios of quasiprojectile and midrapidity emission in the ${}^{64}$Zn + ${}^{64}$Zn reaction at 45 MeV/nucleon
• Full distribution of clusters with universal couplings and in-medium effects
• First results from the INDRA-FAZIA apparatus on isospin diffusion in ${}^{58,64}$Ni+${}^{58,64}$Ni systems at Fermi energies
• Influence of fast emissions and statistical de-excitation on the isospin transport ratio
• Experimental study of the ${}^{40,48}$Ca+ ${}^{40,48}$Ca reactions at 35 MeV/nucleon

Cited by in corpus (5)

• Fast trajectory reconstruction techniques for the large acceptance magnetic spectrometer VAMOS++
• Isospin compositions of correlated sources in the Fermi energy domain
• Isospin diffusion from ${}^{40,48}$Ca${+}^{40,48}$Ca experimental data at Fermi energies: Direct comparisons with transport model calculations
• Revisit to the yield ratio of triton and ${}^3$He as an indicator of neutron-rich neck emission
• Study of quasi-projectile properties at Fermi energies in 48Ca projectile systems