Search

The spectra of photons produced in the interaction between carbon ions of kinetic energy 2.0 and 3.2 GeV per nucleon and beryllium nuclei were measured at the FLINT facility by means of electromagnetic calorimeters that is deployed at the accelerator of the Institute for Theoretical and Experimental Physics (ITEP, Moscow). The spectra in question were measured in the central rapidity region (at angles between 35° and 73° in the laboratory frame) at photon energies of 1 to 3 GeV by using a cumulative-photon trigger. An analysis of the data obtained in this way reveals that the interaction of multinucleon fluctuation in the projectile nucleus with a multinucleon fluctuation in the target nucleus is a dominant process that leads to photon production in the measured region of angles and momenta. As a development of the generally accepted terminology, an interaction of this type may be called a double cumulative interaction.

For 12C9Be interactions at a kinetic beam energy of 3.2 GeV per nucleon, the spectra of photons at laboratory angles in the range 55°–73° were measured off the kinematical region available to the interaction of single nucleons within colliding nuclei. The use of a fast trigger for selecting events involving the production of high-transverse-momentum photons made it possible to measure spectra off the kinematical boundary of four-nucleon interaction. It is shown that the proposed procedure is adequate to the problem of searches for and investigation of flucton-flucton interaction. In the kinematical region where flucton-flucton interaction can manifest itself, the cross sections in question are on the same order of magnitude as respective model predictions. In order to draw definitive conclusions on the role of flucton-flucton interaction, it is highly desirable to extend the angular range of the measurements toward smaller angles.

A half-liter two-phase xenon chamber was built and primary and secondary (proportional) scintillation signals were investigated by using α particles. The energy threshold in the chamber was less than 50 keV of electron equivalent and energy resolution was 18%. The value of the spatial (Z-coordinate) resolution achieved in the time projection chamber was about 0.4 mm.