LEAP 2013 Uppsala SE

ASACUSA (Atomic Spectroscopy And Collisions Using Slow Antiprotons) collaboration at CERN AD pursues multiple goals while sharing the same infrastructure, in particular the radiofrequency quadrupole antiproton decelerator RFQD. We have so far worked on the precision laser and microwave spectroscopy of antiprotonic helium atoms, ionization cross sections for antiproton impact on atoms and...

The precision of laser spectroscopy of antiprotonic helium (a helium atom with one of its electrons replaced by an antiproton) has improved by almost 4 orders of magnitude over its 20 years of history. Experimental transition frequencies can be compared to 3-body QED calculations to derive the antiproton-electron mass ratio. In the latest measurements of the Asacusa ...

A numerical method to calculate the Bethe logarithm for resonant states is developed. To this end we exploit the Complex Coordinate Rotation (CCR) formalism to describe resonances as time-independent solutions of the Schroedinger equation. To get a proper expression for the Bethe logarithm calculations we apply the generalization of the second order perturbation theory to isolated CCR...