Transfer Reaction Spectroscopy with Neutrinoless Double Beta Decay Candidate Nuclei

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This project is a study of the nucleon occupancies of neutrinoless double beta decay candidatenuclei using transfer reactions.Cadmium-116 is a candidate nucleus to decay via neutrinoless double beta decay. It decays totin-116. Should neutrinoless decay in this nucleus be observed by some experiment, it would bepossible to calculate the mass of the neutrino - given the matrix element of the decay is known.Since this is the only process in which this matrix element appears, it must be calculatedtheoretically. As no other process exists which probes the same matrix element then the validityof the calculations is questionable. Nucleon occupancies provide an observable through whichthe models involved in calculating matrix elements can be tested.Neutron transfer reaction spectroscopy is one method of measuring the energies, angularmomentum, and cross sections of nuclear states of interest. A beam of light particles impinges ofa target made of the isotope being studied. For some of these beam particles, a neutron istransferred between the beam and the target. For these reactions, the energies and angularmomenta of states in the residual nucleus can be probed. Through a measurement of thedifferential cross sections for populating these states the single-particle strengths can be extracted- a quantity related to the nucleon occupancies. This has been done for tin-116, the daughter indouble beta decay but not for cadmium-116, the parent. The first part of the project will focus onthese measurements.The other side of the project is rooted in data science. Currently, the department uses a programcalled gf3 to fit spectra. This program calculates fits semi-manually, prompting the user to find aregion of interest and peak positions in that region, then fits skewed Gaussian functions to thepeaks. It then outputs information about the peaks in text in the terminal used to run the program.It would be much more efficient for an automatic fit, with an output of a graph of the fit and itschi-squared, and an output file of peak positions and other parameters. The second part of thisproject will look to producing a program that can do this. A more complete statistical analysis ofthe suitability of choice of input parameters in to transfer reaction modelling will also be carriedout.