Light charged clusters emitted in 32 MeV/nucleon <mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML"><mml:mrow><mml:mmultiscripts><mml:mi>Xe</mml:mi><mml:mprescripts/><mml:none/><mml:mrow><mml:mn>136</mml:mn><mml:mo>,</mml:mo><mml:mn>124</mml:mn></mml:mrow></mml:mmultiscripts><mml:mo>+</mml:mo><mml:mmultiscripts><mml:mi>Sn</mml:mi><mml:mprescripts/><mml:none/><mml:mrow><mml:mn>124</mml:mn><mml:mo>,</mml:mo><mml:mn>112</mml:mn></mml:mrow></mml:mmultiscripts></mml:mrow></mml:math> reactions: Chemical equilibrium and production of <mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML"><mml:mmultiscripts><mml:mi>He</mml:mi><mml:mprescripts/><mml:none/><mml:mn>3</mml:mn></mml:mmultiscripts></mml:math> and <mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML"><mml:mmultiscripts><mml:mi>He</mml:mi><mml:mprescripts/><mml:none/><mml:mn>6</mml:mn></mml:mmultiscripts></mml:math>
Bibliographic record
Abstract
Background: The isovector part of the nuclear equation of state remains partly unknown and is the subject of many studies. The degree of equilibration between the two main collision partners in heavy ion reactions may be used to study the equation of state since it is connected to isospin ($N/Z$) transport properties of nuclear matter.Purpose: We aim to test chemical equilibrium attainment by measuring isotopic characteristics of emitted elements as a function of impact parameter.Method: We study four $^{136,124}\mathrm{Xe}+^{124,112}\mathrm{Sn}$ reactions at 32 MeV/nucleon. The data were acquired with the INDRA detector at the GANIL (Caen, France) facility. Combined (projectile+target) systems are identical for two studied reactions, therefore it is possible to study the path towards chemical equilibrium from different neutron to proton ratio ($N/Z$) entrance channels. The study is limited to identified isotopes detected in the forward part of the center of mass in order to focus on the evolution of projectile-like fragment isotopic content and the benefit of excellent detection performances of the forward part of the apparatus.Results: Light charged particle productions, multiplicities, and abundance ratios dependence against impact parameter are studied. It is measured to almost identical mean characteristics for the two $^{124}\mathrm{Xe}+^{124}\mathrm{Sn}$ and $^{136}\mathrm{Xe}+^{112}\mathrm{Sn}$ systems for central collisions. Comparing all four studied systems it is shown that mean values evolve from projectile $N/Z$ to projectile+target $N/Z$ dependence. Those identical mean characteristics concern all light charged particles except $^{3}\mathrm{He}$ whose mean behavior is strongly different.Conclusions: Our inclusive analysis (no event selection) shows that $N/Z$ equilibration between the projectile-like and the target-like is realized to a high degree for central collisions. The light charged particle production mean value difference between $^{124}\mathrm{Xe}+^{124}\mathrm{Sn}$ and $^{136}\mathrm{Xe}+^{112}\mathrm{Sn}$ systems for central collisions is of the order of a few %. This slight difference could be explained by pre-equilibrium particle emission whose intensity may differ for the two reactions. This point is demonstrated using $^{3}\mathrm{He}$ mean characteristics whose production takes place before chemical equilibrium attainment. The realized $N/Z$ balance between projectile-like and target-like does not imply a pure two-body mechanism. Indeed a midrapidity production of light charged particle does exist and its $N/Z$ is different as compared to the projectile-like one: it is $n$ enriched. This point is touched using $^{6}\mathrm{He}$ midrapidity production which is favored by the drift phenomenon.
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How this classification was reachedexpand
Full frame machine prediction
Teacher imitationNot calibrated prevalence, not ground truth. Human validation pending. The Gemma side is a direct model label for every work in the frame, read from the title-only record. The Codex side is a classifier learned from the 10,348 direct Codex labels and calibrated to design-weighted sample rates; fields without enough sample support carry no Codex call. Candidate is the union of the two sides; consensus is their intersection. These outputs are machine_predicted_unvalidated and are not human labels.
Distilled classifier scores by category (both heads)
| Category | Codex | Gemma |
|---|---|---|
| Metaresearch | 0.000 | 0.001 |
| Meta-epidemiology (narrow) | 0.001 | 0.001 |
| Meta-epidemiology (broad) | 0.000 | 0.001 |
| Bibliometrics | 0.001 | 0.001 |
| Science and technology studies | 0.001 | 0.000 |
| Scholarly communication | 0.002 | 0.001 |
| Open science | 0.001 | 0.001 |
| Research integrity | 0.001 | 0.001 |
| Insufficient payload (model declined to judge) | 0.124 | 0.031 |
Machine scores (provisional)
The two teacher heads of the student model, read on this work. A score orders the frame for review; it never asserts a category, and the validation status ships verbatim with every row.
Baseline scores from an immature model (maturity gate not passed, 7 training rounds). Scores rank; they never assert a category.
score_only:v0-immature-baseline · verbatim from the scoring run: score_only means the number may rank works, and no category label ships from itClassification
machine, unvalidatedMachine predicted; a candidate call from one source (direct Gemma or distilled Codex), not a consensus.
How this classification was reached, model by model and score by score, is at the end of the page under "How this classification was reached".