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The PhD defence and trial lecture are partly digital. The chair of the defence will moderate the disputation.
Ex auditorio questions: the chair of the defence will invite the audience physically present in the auditorium to ask ex auditorio questions.
Trial lecture
Time and place: March 7, 2021; 10:15 AM, Kelvin (V317) - Fysikkbygingen
Title: "Laboratory detection of axions"
Main research findings
The Standard Model, the mathematical description of the interactions of elementary particles, has proven to be a successful framework. Since its finalisation in the 1970s, no significant deviations have been measured from its predictions. However, some phenomena are not currently explained by the Standard Model: What is the nature of dark matter? Can a quantum theory of gravity be constructed? Numerous extensions to the Standard Model have been put forth over the years, trying to answer these, and other, questions about nature. Theoretical extensions of the Standard Model may yield different predictions about nature than the Standard Model itself. Physicists look for evidence of new physics by finding discrepancies from predictions, for example in particle collision experiments.
We search for discrepancies to the Standard Model predictions by analysing proton-proton collision data collected by the ATLAS detector at the Large Hadron Collider, located at the CERN particle physics laboratory in Switzerland. Specifically, we select particle collision events for analysis where the final state of the collisions are two electrons or muons. We perform two separate searches for new physics on this dataset. The first is a search for so-called resonant phenomena, manifesting as localised deviations from the Standard Model prediction, in the reconstructed mass of the selected lepton pairs. The second search is for non-resonant phenomena, where the new physics is expected to appear as broad deviations to the Standard Model predictions in the high mass region of the data. In both searches, the Standard Model background prediction is estimated by fitting a functional form to the data.
No significant deviation from the background estimate is observed in either search. We set upper limits on the cross-section of a generic dilepton resonance and lower limits on the mass of a potential new heavy neutral boson. We also set lower limits on the so-called string scale parameter of the Arkani-Hamed, Dimopoulos, and Dvali model of large extra dimensions. This model may explain the discrepancy in strength between the particle interactions of the Standard Model, and gravity.
Candidate contact information
Phone number: 90262133
Adjudication Committee
- Professor Else Lytken, Lund University, Sweden
- Professor Jan Conrad, Stockholm University, Sweden
- Professor Trine Spestad Tveter, University of Oslo, Norway
Supervisors
- Professor Farid Ould-Saada, Department of Physics, University of Oslo, Norway
- Dr. Magnar Kopangen Bugge, GE Vingmed Ultrasound AS, Norway
(former: Department of Physics - UiO)
Chair of defence
- Professor Anette Eleonora Gunnæs, Department of Physics, University of Oslo, Norway
Contact information to Department: Line Trosterud Resvold