Transfer Reaction Spectroscopy with Neutrinoless Double Beta Decay Candidate Nuclei
Lead Research Organisation:
University of Manchester
Department Name: Physics and Astronomy
Abstract
This project is a study of the nucleon occupancies of neutrinoless double beta decay candidate
nuclei using transfer reactions.
Cadmium-116 is a candidate nucleus to decay via neutrinoless double beta decay. It decays to
tin-116. Should neutrinoless decay in this nucleus be observed by some experiment, it would be
possible 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 calculated
theoretically. As no other process exists which probes the same matrix element then the validity
of the calculations is questionable. Nucleon occupancies provide an observable through which
the models involved in calculating matrix elements can be tested.
Neutron transfer reaction spectroscopy is one method of measuring the energies, angular
momentum, and cross sections of nuclear states of interest. A beam of light particles impinges of
a target made of the isotope being studied. For some of these beam particles, a neutron is
transferred between the beam and the target. For these reactions, the energies and angular
momenta of states in the residual nucleus can be probed. Through a measurement of the
differential 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 in
double beta decay but not for cadmium-116, the parent. The first part of the project will focus on
these measurements.
The other side of the project is rooted in data science. Currently, the department uses a program
called gf3 to fit spectra. This program calculates fits semi-manually, prompting the user to find a
region of interest and peak positions in that region, then fits skewed Gaussian functions to the
peaks. 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 its
chi-squared, and an output file of peak positions and other parameters. The second part of this
project will look to producing a program that can do this. A more complete statistical analysis of
the suitability of choice of input parameters in to transfer reaction modelling will also be carried
out.
nuclei using transfer reactions.
Cadmium-116 is a candidate nucleus to decay via neutrinoless double beta decay. It decays to
tin-116. Should neutrinoless decay in this nucleus be observed by some experiment, it would be
possible 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 calculated
theoretically. As no other process exists which probes the same matrix element then the validity
of the calculations is questionable. Nucleon occupancies provide an observable through which
the models involved in calculating matrix elements can be tested.
Neutron transfer reaction spectroscopy is one method of measuring the energies, angular
momentum, and cross sections of nuclear states of interest. A beam of light particles impinges of
a target made of the isotope being studied. For some of these beam particles, a neutron is
transferred between the beam and the target. For these reactions, the energies and angular
momenta of states in the residual nucleus can be probed. Through a measurement of the
differential 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 in
double beta decay but not for cadmium-116, the parent. The first part of the project will focus on
these measurements.
The other side of the project is rooted in data science. Currently, the department uses a program
called gf3 to fit spectra. This program calculates fits semi-manually, prompting the user to find a
region of interest and peak positions in that region, then fits skewed Gaussian functions to the
peaks. 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 its
chi-squared, and an output file of peak positions and other parameters. The second part of this
project will look to producing a program that can do this. A more complete statistical analysis of
the suitability of choice of input parameters in to transfer reaction modelling will also be carried
out.
Studentship Projects
| Project Reference | Relationship | Related To | Start | End | Student Name |
|---|---|---|---|---|---|
| ST/P006795/1 | 01/10/2017 | 30/09/2024 | |||
| 2025712 | Studentship | ST/P006795/1 | 01/10/2017 | 31/03/2022 | Bethan Cropper |
| Description | I'm a Scientist, Get Me Out of Here |
| Form Of Engagement Activity | Engagement focused website, blog or social media channel |
| Part Of Official Scheme? | No |
| Geographic Reach | National |
| Primary Audience | Schools |
| Results and Impact | I answered questions on a website from school children. They could ask whatever they wanted. The point was to humanise scientists, so pupils could see themselves doing it rather than faceless white coats. |
| Year(s) Of Engagement Activity | 2020 |
| URL | https://imascientist.org.uk/ |