1 Evolution of Cluster Production with Fragmentation Degree
3
Fig. 1.1 Left panel: evolution of the Z max observable distributions; the Y-scale corresponds to
absolute measured cross sections in mb, see [5] for details. Right panel: mean evolution of the total
multiplicity of charged produced (M Z ≥1 ) with the Z max observable. The different markers and
colors stand for seven beam energies used in the analysis. The cartoon below the panels illustrates
how the partitions evolve with fragmentation degree. The black arrow indicates the region where
we observe differences in the trends when looking at one beam energy to another, see the test for
details
pendent of the reaction mechanism minimizing possible experimental bias. Finally,
as
58 Ni+
58 Ni is a symmetric system, it gives, on average, a good description of what
happens for the whole system. As we choose Z max as the sorting observable, we
have to be sure that if this is present in the selected partitions or not. That’s why
we keep only events with a missing charge less than 5 compared to the
58 Ni charge
(Z
(FW )
tot
≥ 24). With this condition, we ensure that the Z max fragment is part of the
event on the whole range of fragmentation degree.
In Fig. 1.1, the left panel shows distributions of the Z max observable for the selected
events, while the right panel shows the mean evolution of total charged multiplicity
(M Z ≥1 ) with Z max . The different markers and colors stand for the seven beam energies. The Z max distributions show the population of the whole range of fragmentation
with a significant cross section. Increasing beam energies, we observe the expected
continuous evolution from evaporation to vaporization events. The mean evolution
of total charged multiplicity follows at first order, the conservation of nucleons: more
the partition is fragmented, more the number of fragments are important. Nevertheless, we observe already interesting behavior in the intermediate values of Z max for
the lowest beam energies: after a linear increase of M Z ≥1 in the evaporation regime,
the trend is dampened before it goes back in the vaporization regime. This intermediate regime is softned when beam energy becomes higher with an overall correlation
more close to a monotonic increase. It is coherent with a scenario where the partitions
are produced under constraints in the multifragmentation regime.
3
Fig. 1.1 Left panel: evolution of the Z max observable distributions; the Y-scale corresponds to
absolute measured cross sections in mb, see [5] for details. Right panel: mean evolution of the total
multiplicity of charged produced (M Z ≥1 ) with the Z max observable. The different markers and
colors stand for seven beam energies used in the analysis. The cartoon below the panels illustrates
how the partitions evolve with fragmentation degree. The black arrow indicates the region where
we observe differences in the trends when looking at one beam energy to another, see the test for
details
pendent of the reaction mechanism minimizing possible experimental bias. Finally,
as
58 Ni+
58 Ni is a symmetric system, it gives, on average, a good description of what
happens for the whole system. As we choose Z max as the sorting observable, we
have to be sure that if this is present in the selected partitions or not. That’s why
we keep only events with a missing charge less than 5 compared to the
58 Ni charge
(Z
(FW )
tot
≥ 24). With this condition, we ensure that the Z max fragment is part of the
event on the whole range of fragmentation degree.
In Fig. 1.1, the left panel shows distributions of the Z max observable for the selected
events, while the right panel shows the mean evolution of total charged multiplicity
(M Z ≥1 ) with Z max . The different markers and colors stand for the seven beam energies. The Z max distributions show the population of the whole range of fragmentation
with a significant cross section. Increasing beam energies, we observe the expected
continuous evolution from evaporation to vaporization events. The mean evolution
of total charged multiplicity follows at first order, the conservation of nucleons: more
the partition is fragmented, more the number of fragments are important. Nevertheless, we observe already interesting behavior in the intermediate values of Z max for
the lowest beam energies: after a linear increase of M Z ≥1 in the evaporation regime,
the trend is dampened before it goes back in the vaporization regime. This intermediate regime is softned when beam energy becomes higher with an overall correlation
more close to a monotonic increase. It is coherent with a scenario where the partitions
are produced under constraints in the multifragmentation regime.