Hamburg 2009 – scientific programme

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A: Fachverband Atomphysik

A 34: Poster II

A 34.24: Poster

Thursday, March 5, 2009, 16:30–19:00, VMP 9 Poster

Collisions of low-energy antiprotons — •Armin Lühr and Alejandro Saenz — Humboldt-Universität zu Berlin, Institut für Physik, Moderne Optik, Hausvogteiplatz 5-7, D-10117 Berlin

During the last decades advances have been achieved in the understanding of antiproton (p) collisions with the simplest one- and two-electron atoms H and He. However, in the case of p + He experiment and theory did not agree for impact velocities below the mean electron velocity for more than a decade stimulating a vivid theoretical activity. Additionally, the conditions for the production of slow antiproton beams already achieved at the antiproton decelerator AD at CERN will strongly improve with the upcoming low-energy p facility FLAIR at GSI. This provides the basis for fundamental physics like tests of the CPT-invariance or gravity of antimater. Accurate p collision data can be used for stringent tests of different theoretical approaches.

Theoretical investigations for collisions of p with atomic and molecular hydrogen [1], helium as well as the alkali metal atoms [2] Li, Na, K, and Rb in an energy range from 1 keV to 6 MeV were performed. Cross sections for excitation and ionization as well as electron-energy spectra and stopping power are presented together with comparisons to results for proton collisions. The calculations are based on a time-dependent close coupling approach. The present calculations should also be useful for the design of the new FLAIR facility where, e.g., the interaction of p with residual-gas atoms is important.

[1] A. Lühr and A. Saenz, Phys. Rev. A 78, 032708 (2008)

[2] A. Lühr and A. Saenz, Phys. Rev. A 77, 052713 (2008)