Experimental studies of fission induced in relativistic nuclear collisions show a systematic enhancement of the excitation energy of the primary fragments by a factor of ∼2, before their decay by fission and other secondary fragments. Although it is widely accepted that by doubling the energies of the single-particle states may yield a better agreement with fission data, it does not prove fully successful, since it is not able to explain yields for light and intermediate mass fragments. State-of-the-art calculations are successful to describe the overall shape of the mass distribution of fragments, but fail within a factor of 2-10 for a large number of individual yields. Here, we present a novel approach that provides an account of the additional excitation of primary fragments due to final state interaction with the target. Our method is applied to the ^{238}U+^{208}Pb reaction at 1  GeV/nucleon (and is applicable to other energies), an archetype case of fission studies with relativistic heavy ions, where we find that the large probability of energy absorption through final state excitation of giant resonances in the fragments can substantially modify the isotopic distribution of final fragments in a better agreement with data. Finally, we demonstrate that large angular momentum transfers to the projectile and to the primary fragments via the same mechanism imply the need of more elaborate theoretical methods than the presently existing ones.

中文翻译：

---

相对论核的裂变与碎片激发和重新定向。

相对论核碰撞引起的裂变的实验研究表明，在裂变和其他次级碎片衰减之前，初级碎片的激发能有系统地提高了约2倍。尽管人们普遍认为通过使单粒子态的能量加倍可以与裂变数据更好地达成一致，但是由于不能解释轻质和中等质量碎片的产率，因此并没有完全成功。最新的计算成功地描述了碎片质量分布的整体形状，但是对于大量的单个产量而言，失败率在2-10的范围内。在这里，我们提出了一种新颖的方法，该方法提供了由于与目标的最终状态相互作用而导致的主要片段额外激发的原因。我们的方法适用于1 GeV /核子的^ {238} U + ^ {208} Pb反应（并且适用于其他能量），这是具有相对论重离子的裂变研究的典型案例，在该案例中，我们发现通过片段中巨大共振的最终状态激发来吸收能量，可以更好地与数据更好地改变最终片段的同位素分布。最后，我们证明，大角动量通过相同的机制传递到弹丸和初级碎片意味着比目前现有的方法需要更复杂的理论方法。我们发现，通过碎片中巨大共振的最终状态激发而吸收能量的大概率可以实质性地修饰最终碎片的同位素分布，从而与数据更好地吻合。最后，我们证明，大角动量通过相同的机制传递到弹丸和初级碎片意味着比目前现有的方法需要更复杂的理论方法。我们发现，通过碎片中巨大共振的最终状态激发而吸收能量的大概率可以实质性地修饰最终碎片的同位素分布，从而与数据更好地吻合。最后，我们证明，大角动量通过相同的机制传递到弹丸和初级碎片意味着比目前现有的方法需要更复杂的理论方法。