The PhD defence and trial lecture will be streamed. 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.
→ Live streaming of trial lecture and disputation
→ Request for thesis copy (available until the disputation starts)
Trial lecture
Time and place: September 15, 2023; 10:15 AM, Store Fysiske auditorium (V343) - Fysikkbygningen
Title: "The mystery of the muon anomalous magnetic dipole moment, g-2"
Main research findings
The Standard Model of particle physics, describing the fundamental constituents (the matter particles) and their interactions (the forces), is undoubtedly one of the greatest triumphs of modern physics. However, the Standard Model is not believed to be the final theory of particle physics. For instance, it does not include gravity or explain dark matter. Supersymmetry (SUSY) is a popular proposed extension of the Standard Model -- predicting the existence of many new particles -- that can accomodate several of the shortcomings of the Standard Model simultaneously. No experimental signs of supersymmetry have yet been observed, but the search continues. The topic of this thesis is the search for so-called electroweak supersymmetry in proton-proton collision data collected by the ATLAS detector at the Large Hadron Collider between 2015 and 2018. More specifically, the search for chargino-neutralino pair production, where the lightest neutralino is considered to be a viable dark-matter candidate. By designing sophisticated analyses, we search for discrepancies with Standard Model predictions. No significant excess above the Standard Model predictions is found in the data. However, the results presented surpass previous sensitivity and set some of the most stringent limits in the world on the models chosen for interpretation.
Hovedfunn (Norwegian)
Standardmodellen for partikkelfysikk, som beskriv dei fundamentale bestanddelane (materiepartiklane) og interaksjonane deira (kreftene), er utvilsamt ein av dei største triumfane i moderne fysikk. Likevel er ikkje standardmodellen venta å vere den endelege teorien for partikkelfysikk. Til dømes inkluderer han ikkje gravitasjon og forklarar ikkje mørk materie. Supersymmetri (SUSY), ei populær føreslått utviding av standardmodellen, spår eksistensen av mange nye partiklar og kan løyse fleire av problema med standardmodellen samstundes. Ingen eksperimentelle teikn på supersymmetri har blitt observert enno, men søket held fram. Temaet for denne avhandlinga er søk etter såkalt elektrosvak supersymmetri i datasettet av proton-proton-kollisjonar samla inn med ATLAS-detektoren ved Large Hadron Collider mellom 2015 og 2018. Meir spesifikt søk etter parproduksjon av ladino og nøytralino, kor det lettaste nøytralinoet er rekna for å vere ein mogleg kandidat for mørk materie. Ved å designe sofistikerte analysar søkjer vi etter avvik frå standardmodellen sine prediksjonar i datasettet. Ingen signifikante avvik frå standardmodellen sine prediksjonar blir funne. Men dei presenterte resultata overgår tidlegare sensitivitet og set nokre av dei strengaste grensene i verda for modellane valde for tolking.
Adjudication Committee
- Professor Alexander Tapper, Imperial College London, UK
- Professor Christophe Clement, Department of Physics, Stockholm University, Sweden
- Professor Larissa Bravina, Department of Physics, University of Oslo, Norway
Supervisors
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Professor Heidi Sandaker, Department of Physics, University of Oslo, Norway
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Professor Farid Ould-Saada, Department of Physics, University of Oslo, Norway
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Dr. Eirik Gramstad, Department of Physics, University of Oslo, Norway
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Dr. Sara Alderweireldt, Institute for Particle and Nuclear Physics, the University of Edinburgh, Scotland
Chair of defence
- Head of Department Susanne Friederike Viefers, Department of Physics, University of Oslo, Norway
Contact information to Department: Line Trosterud Resvold