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

  • Positronium
  • Hyperfine splitting
  • Ultrasoft

• Graduation date

  Fall 2011

• Type of Item

  Thesis

• Degree

  Master of Science

• DOI

  https://doi.org/10.7939/R3762V

• 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.