A quest for exotic nuclear systems formed in the reaction at 23 AMeV

dc.abstract.enIn this dissertation the possibility of creation of toroidal-shape freeze-out configurations in $^{197}Au + ^{197}Au$ reaction at 23 AMeV has been investigated using CHIMERA $4\pi$ multidetector. In this work the information about particles was obtained using $\Delta E − E$ and ToF methods from over 1000 detection cells covering the polar angle from $3.1^{\circ}$ to $130^{\circ}$ and full range ($2\pi$) of azimuthal angle. The long and complicated energy, charge, and mass calibration procedures for all detectors were conducted. There was selected the class of complete events for which the total charge of identified fragments is close to the total charge of the system and the total parallel linear momentum is close to the linear momentum of the projectile. There was investigated the reaction scenario for the multifragmentation of the composite nuclear system formed in central collisions. The events with five or more fragments were chosen for further analysis. The experimental data were compared with statical and dynamical theoretical predictions using ETNA and QMD models. The novel shape sensitive observables: $\delta$ and $\Delta^{2}$ were used to determine the shape of created nuclear systems. Additionally, in the connection with above mentioned observables two angles were defined: $\theta_{flow}$ and $\theta_{plane}$, respectively. The dependence between $\theta_{flow}$, $\theta_{plane}$ and impact parameter in QMD model predictions were used to reduce contribution of non-central collisions. The possibility of formation of toroidal-shape nuclei was demonstrated by the efficiency factor. The efficiency factor for Ball $8V_{0}$, Bubble $8V_{0}$, Toroid 12 fm, Toroid 15 fm and QMD was calculated and compared with that for experimental data. Proximity of efficiency factor values for experimental data and toroidal freeze-out configurations may be used as an indication of the formation of an exotic freeze-out configuration. The juxtaposition of the standard deviation of fragment mass values for class events located outside and inside the reaction do not support the hypothesis of toroidal freeze-out configuration formation. Comparison of distributions of relative velocities for event with different orientation in respect to reaction plane gives evidence that the freeze-out configuration is more extended for class events located outside reaction plane. The behavior of mean velocities of fragments as a function of their mass for flat and non-flat events gives an indication that toroidal configuration may be created for some subclass of flat events. The probability of appearance of this flat events is much greater than the prediction of the QMD model. The nature of flat events tilted with respect to the reaction plane should be investigated. The related analysis is in progress.pl
dc.affiliationWydział Fizyki, Astronomii i Informatyki Stosowanej : Instytut Fizyki im. Mariana Smoluchowskiegopl
dc.contributor.advisorPłaneta, Roman - 100063 pl
dc.contributor.authorNajman, Rafał - 103646 pl
dc.contributor.institutionJagiellonian University. Marian Smoluchowski Institute of Physics. Department of Hot Matter Physicspl
dc.contributor.reviewerFornal, Bogdanpl
dc.contributor.reviewerKisiel, Janpl
dc.description.accesstimew momencie opublikowania
dc.description.additionalBibliogr. s. 69-71pl
dc.description.physical[5], 71pl
dc.description.versionostateczna wersja autorska (postprint)
dc.identifier.callnumberDokt. 2015/289pl
dc.identifier.projectROD UJ / OPpl
dc.rights.simpleviewWolny dostęp
dc.share.typeotwarte repozytorium
dc.subject.enexotic nucleipl
dc.subject.encalibration procedurespl
dc.subject.enstatic and dynamic modelspl
dc.subject.pljądra egzotycznepl
dc.subject.plprocedury kalibracyjnepl
dc.subject.plmodele statyczne i dynamicznepl
dc.titleA quest for exotic nuclear systems formed in the $^{197}Au + ^{197}Au$ reaction at 23 AMeVpl
dc.title.alternativePoszukiwanie egzotycznych układów jądrowych formowanych w reakcji $^{197}Au + ^{197}Au$ przy energii 23 AMeVpl

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