Science Hall Colloquium discusses antimatter

Beth McHenry

Joan Marler, a fellow in the physics department, presented the research she conducted on antimatter at the University of California, San Diego in a Science Hall Colloquium Wednesday. “When Antimatter Attacks …” described Marler’s work and also addressed general information and misconceptions about antimatter.
Marler began her presentation by pointing out some popular misconceptions about antimatter. Author Dan Brown’s first novel, “Angels and Demons,” bases its premise on the production of powerful and dangerous antimatter. Marler explained to the audience that laboratories like CERN in Switzerland and Fermilab in Batavia, Ill. have been producing antimatter for the past 10 years, but as of yet it is still a threat to public safety only in fiction.
According to Marler, there are three big questions about antimatter to consider: How can we explain the asymmetry in the amount of antimatter and matter we see? Can we develop a fundamental chemistry for the interactions of antimatter with matter? Are there any practical applications for antimatter?
The theory behind antimatter is that each particle has an anti-particle with an equal mass and an opposite charge. Theoretically, equal amounts of matter and antimatter were produced during the big bang, but the observed interactions between antimatter and matter make this theory questionable. When antimatter and matter collide, both particle and anti-particle annihilate, which leads scientists to wonder why the particles in the universe did not spontaneously annihilate immediately.
Besides annihilation, the collision also produces gamma rays, pions or both, depending on the type of antimatter. Physicists believe that the products of this collision can be harnessed for various useful purposes, but very little is currently known about interactions involving antimatter.
Marler’s experimentation was meant to develop a deeper understanding of the interactions of antimatter with matter. To achieve this end, Marler aimed to create dense, low-energy plasma of positrons – the antimatter of the electron – and to study in-depth the theoretical calculations of other research groups.
The ultimate goal was to gather absolute, low-energy, high-resolution measurements of antimatter interactions. In order to achieve this end, it was necessary to trap and study positrons, an extremely difficult task. The interactions that were then studied included elastic scattering, inelastic scattering, ionization and direct annihilation. Through this experiment, Marler’s study was able to contribute to the growing store of knowledge about antimatter and the reliable techniques that may be used to gather antimatter data.
To conclude, Marler discussed some of the possible uses for antimatter that the scientific community is currently investigating. Future practical applications may include energy propulsion, cancer detection or removal and materials analysis. At this point, the expense and time involved in producing antimatter are both so large that any practical applications would not be feasible on a large scale. However, physics research projects like Marler’s experiments are gradually widening our understanding of antimatter and its uses.