Applicability Conditions of the Hydrodynamical Model of Multiple Production of Particles from the Point of View of Quantum Field Theory
Applicability Conditions of the Hydrodynamical Model of Multiple Production of Particles from the Point of View of Quantum Field Theory
复制标题
量子场论视角下粒子多重生成流体动力学模型的适用条件
DOI：
10.1143/ptp.22.403
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发表时间：
1959
期刊：
影响因子：
--
通讯作者：
M. Namiki
中科院分区：
文献类型：
--
作者：
C. Iso;K. Mori;M. Namiki
在量子场论的框架下，试图探讨流体力学描述是否适用于朗道粒子多重产生理论中所考虑的核子在高能碰撞中产生的介子云。基于不可逆过程的量子统计力学方法制备的局部平衡和介子云中局部系统的可能性条件构成了流体力学模型的适用性条件。这些条件是通过将介子流体的相关长度和弛豫时间与特征长度和时间进行比较来检验的，在特征长度和时间中，流体的热力学参数，例如温度，在宏观尺度上有明显的减少或增加。从这些检验中可以得出结论，在整个云扩散到一个大小为相关长度数量级的区域之后，除了云的前部之外，水动力模型几乎在所有地方都成立。强调碰撞后的初始云团和膨胀云团前部的相互作用不能用任何统计定律或流体力学来描述。锋面粒子从未处于任何热平衡状态的事实表明，它们记得非常小的云团中初始高能相互作用的一些特征。可以推断，前沿粒子的分布（例如K/ pi比和动量或角分布）可以提供非常小距离上相互作用的信息。初始相互作用对剩余云的影响仅通过流体动力学方程的初始边界条件来考虑。另外，指出朗道所采用的完美流体假设也不太好；结果表明，通过最终的相互作用，我们可以预期粒子数量的增加。最后讨论了这些特征是否与最近的实验相符。(身份验证)«更少
In the framework of quantam field theory, it is attempted to investigate whether the hydrodynamical description is applicable to the meson cloud produced in extremely high energy collisions of nucleons as considered in Landau's theory of the multiple production of particles. The applicability conditions of the hydrodynamical model consist of local equilibrium and conditions for the possibilities of defining the local system in the meson cloud, which are prepared by the methods based on quantum statistical mechanics of irreversible processes. These conditions are examined by cornparison of the correlation lengths and the relaxation times of the meson fluid with a characteristic length and time, in which the thermodynamical parameters, the temperature for example, of the fluid decrease or increase by an appreciable amount on a macroscopic scale. From such examinations, it may be concluded that the hydrodynamical model holds almost everywhere except ia the front part of the cloud after the whole cloud spreads over a region whose size is the order of the correlation length. It is ernphasized that the interactions in the initisl cloud directly ater collision and in the front part of the expanding cloud can never be described by any statistical law or hydrodynamics. The factmore » that the front particles are never in any thermal equilibrium suggests that they remember some features of initial high energy interactions in the very small cloud. It is inferred that the distributions (for example, K/ pi ratio and the momentum or angular distribution) of the front particles may be informative about the interactions at very small distances. The influenees of initial interactions on the remaining cloud are only taken into account through the initial boundary conditions for the hydrodymical equation. In addition, it is pointed cut that the assumption of the perfect fluid used by Landau is not so good; it turns out that one can expect an increment of the number of particles through the final interactions. Finally it is discussed whether these characteristics may be consistent with the recent experiments. (auth)« less