8–13 Sept 2025
Integrated Innovation Building (IIB), RIKEN Kobe Campus
Asia/Tokyo timezone
Registration is closed. We look forward to seeing you in Kobe!

Status Report of the ASY_EOS II Experiment And Isotopic Transparency in Central Xe+Sn Collisions at 100 MeV/nucleon

10 Sept 2025, 09:20
30m
Auditorium (8F) (Integrated Innovation Building (IIB), RIKEN Kobe Campus)

Auditorium (8F)

Integrated Innovation Building (IIB), RIKEN Kobe Campus

Minatojima-minamimachi 6-7-1, Kobe, Japan
2. Heavy-ion collision experiments and transport model simulations NuSym Scientific Session

Speaker

Arnaud Le Fèvre (GSI Darmstadt)

Description

Our presentation will be 2 fold.
The first part will be a short status report of the second campaign of the ASY-EOS experiment held at GSI Darmstadt in March 2025, with the measurement of Au+Au collisions between 0.28 and 1 GeV/nucleon. This new experiment aims at constraining the symmetry energy of nuclear matter at larger densities (about 2.5 times saturation density) with higher accuracy as regard to the first campaign (2011) that has triggered a breakthrough in the knowledge of the symmetry energy at supra-saturation density using heavy-ion collisions.
The second part will concern our recent publication presenting a new method to measure the isotopic transparency in central heavy-ion collisions. This method is based on comparing isotopic yield ratios measured at forward and sideward polar angles and on cross-bombarding heavy nuclei with different neutron-to-proton ratios. We used here measurements of central collisions of isotopically separated $^{124,129}$Xe+$^{112,124}$Sn at 100 MeV/nucleon bombarding energy, measured with the 4π multidetector INDRA at GSI. We found a moderate transparency for hydrogen isotopes, and a high transparency exceeding 50% for heavier fragmentation products with atomic number Z ≥ 3. An anomalously large transparency has been found for alpha particles, and possible explanations will be presented.

Presentation Style Invited Speaker

Author

Arnaud Le Fèvre (GSI Darmstadt)

Presentation materials