Ultrasoft Contribution to the Positronium Hyperfine Splitting

  • Author / Creator
    Marcu, Simona Rahela
  • Positronium consists of an electron and positron in a bound state, a purely leptonic system and therefore an excellent test of QED (quantum electrodynamics). The ground state is characterized by two different spin configurations: spin-singlet and spin-triplet states. The difference between the corresponding energy levels is called the hyperfine splitting. Currently the discrepancy between theory and experiment is 3.9 standard deviations for this quantity. We are computing the ultrasoft contribution to the positronium hyperfine splitting. It represents the time-delayed exchange of a photon with energy of the order of the binding energy between the electron and positron. The full theoretical expression of the ultrasoft contribution was found using perturbation theory, and expansion of the positronium wavefunction at the origin about the Coulomb approximation. The expression was then evaluated using Mathematica and asymptotic approximations have been made when an exact numerical value could not be computed. The final result increases the discrepancy to 4.3 standard deviations. New experimental results are needed in order to solve the discrepancy.

  • Subjects / Keywords
  • Graduation date
  • Type of Item
  • Degree
    Master of Science
  • DOI
  • License
    This thesis is made available by the University of Alberta Libraries with permission of the copyright owner solely for non-commercial purposes. This thesis, or any portion thereof, may not otherwise be copied or reproduced without the written consent of the copyright owner, except to the extent permitted by Canadian copyright law.
  • Language
  • Institution
    University of Alberta
  • Degree level
  • Department
    • Department of Physics
  • Supervisor / co-supervisor and their department(s)
    • Penin, Alexander (Physics)
  • Examining committee members and their departments
    • Prus-Czarnecki, Andrzej (Physics)
    • Troitsky, Vladimir (Mathematics)
    • Kravchinsky, Vadim (Physics)