FIAS Scientific Report 2011 - Frankfurt Institute for Advanced Studies ...

Production of hyper-nuclei in reactions with relativistic ions
Collaborators: A.S. Botvina, K.K. Gudima 1 , J. Steinheimer, I.N. Mishustin, M. Bleicher, H. Stöcker
1 Institute of Applied Physics, Academy of Sciences of Moldova
We formulate a hybrid approach for describing formation of hyper-nuclei in peripheral collisions of relativistic
light and heavy ions. The initial dynamical stage is simulated with transport models: the Dubna cascade model
(DCM) and the ultra-relativistic quantum molecular dynamics (UrQMD) model. During this stage nucleons
from the overlapping parts of the projectile and target (participant zone) interact intensively between themselves
and with other hadrons produced in primary and secondary collisions. The hyperons (Y = Λ,Σ,Ξ,Ω),
produced in these interactions, can later on be captured by the projectile and target spectator residues (i.e.,
non-overlapping parts of colliding ions). In the Figure we demonstrate probabilities for producing spectator
residues with different numbers of captured Λs together with their mean masses.
At the next stage these excited spectators will decay with production of normal and hyper-nuclei. For description
of this process the statistical models of multifragmentation and Fermi-break-up were used. It was shown
that a large variety of hypernuclei, including multi-strange and neutron-rich ones, can be formed in this way.
We have performed analysis of preliminary experimental data on yields of light hypernuclei in projectile fragmentation
reactions, reported recently by HypHI collaboration at GSI. We have found that the production of
3
ΛH, 4 ΛH, as well as exotic Λn ound state, which was never observed before, can be naturally explained within
our approach.
probability
A (residual mass)
2 A GeV
Au+Au
p+Au
H (number of hyperons)
20 A GeV
DCM
UrQMD
Figure: Probability for formation of conventional
and strange spectator residuals (top panels), and their
mean mass numbers (bottom panels) vs the number
of captured Λ hyperons (H), calculated with DCM
and UrQMD model for p + Au and Au + Au collisions
with energy of 2 GeV per nucleon (left panels),
and 20 GeV per nucleon (right panels).
Related publications and talks in 2011:
1) A.S. Botvina, K.K. Gudima, J. Steinheimer, I.N. Mishustin, J. Pochdzalla, A. Sances-Lorente, M. Bleicher,
H. Stöcker, Production of hyper-nuclei in peripheral collisions of relativistic ions, mini-review to be published
in Nucl. Phys. A.
2) A.S. Botvina et al., Production of hyper-nuclei in reactions induced by relativistic light- and heavy-ions,
invited talk at the International Workshop “Strange Hadronic Matter” (ETC*, Trento, Italy, September 26-30,
2011).
3) A.S. Botvina et al., Production of spectator hypermatter in relativistic light- and heavy-ion collisions, talk at
the Third International Conference on Nuclear Fragmentation - NUFRA2011 (Kemer, Antalya, Turkey, October
2-9, 2011).
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