Neutral strange particle spectra with direct daughter particle identification in 11.6A GeV/c Au+Au collisions
Kainz, Kristofer K.
Llope, William J.
Doctor of Philosophy
The BNL-AGS Experiment 896 intended to measure neutral strange particles, including the Λ hyperon and Ks meson, by recognizing and reconstructing their charged decay daughters. As designed, E896 had no means of directly identifying the species of these daughters, which is a powerful tool for the rejection of certain background processes that can mimic the signatures of such decays. A Time-Of-Flight (TOF) detector system was thus added to this experiment to provide a means for direct particle identification of the charged decay products. The detectors were constructed and installed in the E896 apparatus, and experimental data was collected with these new detectors during several runs of the experiment both with single hadron beams and central collisions of gold nuclei at a beam momentum of 11.6 GeV/c/N. Software was written to calibrate the raw TOF detector information, to make the crucial association of tracks in the experiment to hits in the TOF system, and to optimize the timing performance and particle identification capabilities. This software was then used to form samples of reconstructed neutral strange particles under the more stringent criteria possible with the addition of the TOF information to the E896 data. The transverse mass distributions of Λ hyperons and Ks mesons from central 11.6 GeV/c/N Au+Au collisions, obtained from the analyses including direct daughter particle identification, will be presented and compared with other experiments and a theoretical model.
Particle physics; Elementary particles; High energy physics