One of the problems in the analysis of nucleus-nucleus collisions is
to get information on the value of the impact parameter b. This work
consists in the application of pattern recognition techniques aimed at
associating values of b to groups of events. To this end, a support vec-
tor machine (SVM) classifier is adopted to analyze multifragmentation
reactions. This method allows to backtracing the values of b through
a particular multidimensional analysis. The SVM classification con-
sists of two main phase. In the first one, known as training phase,
the classifier learns to discriminate the events that are generated by
two different model:Classical Molecular Dynamics (CMD) and Heavy-
Ion Phase-Space Exploration (HIPSE) for the reaction: 58Ni +48 Ca
at 25 AMeV. To check the classification of events in the second one,
known as test phase, what has been learned is tested on new events
generated by the same models. These new results have been com-
pared to the ones obtained through others techniques of backtracing
the impact parameter. Our tests show that, following this approach,
the central collisions and peripheral collisions, for the CMD events,
are always better classified with respect to the classification by the
others techniques of backtracing. We have finally performed the SVM
classification on the experimental data measured by NUCL-EX col-
laboration with CHIMERA apparatus for the previous reaction.
| Identifer | oai:union.ndltd.org:unibo.it/oai:amsdottorato.cib.unibo.it:851 |
| Date | 05 June 2008 |
| Creators | De Sanctis, Jacopo <1977> |
| Contributors | Bruno, Mauro |
| Publisher | Alma Mater Studiorum - Università di Bologna |
| Source Sets | Università di Bologna |
| Language | English |
| Detected Language | English |
| Type | Doctoral Thesis, PeerReviewed |
| Format | application/pdf |
| Rights | info:eu-repo/semantics/openAccess |
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