Evidence for Two Body Break Up at a Unique Temperature in High Energy P-Xe and P-Kr Collisions
This experiment was conducted at FNAL. Using the newly developed warm gas jet facility, hydrogen-noble gas mixtures were injected into the circulating proton beam. During injection, the beam was accelerated between 20 to 400 GeV/c. The target mixtures reported here were 90% H2 — 10% Xe and 82% H2 — 18% Kr by partial pressures. Fragments, emerging from the interaction region, were accepted if they satisfied the ΔE · E · VETO trigger. A typical mass spectrum is shown in Fig. 1. In attempting to find a mass independent disintegration temperature, we plotted the kinetic energy distributions for each fragment mass emerging from Xenon and Krypton. To our surprise, the inverse logaritmic slope, (temperature) varied between 15 and 20 MeV, about a factor of two larger than the nuclear binding energy shown in Fig. 2. There is a clear break in the mass dependence of the temperature in the Carbon-Nitrogen mass range. In trying to understand the origin of this mass dependence, we were able to show that those fragments which are heavier than Carbon had emerged as a decay product of a common parent (progenitor). The mass of this progenitor is denoted by A*P and it is about twenty nucleon masses less than the target mass (A*P ≈ A−20).
KeywordsFragment Mass Mass Dependence Nucleon Masse Target Mass Common Parent
Unable to display preview. Download preview PDF.