Hannover 2013 – wissenschaftliches Programm

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A: Fachverband Atomphysik

A 30: Poster: Interaction with VUV and X-ray light

A 30.11: Poster

Mittwoch, 20. März 2013, 16:00–18:30, Empore Lichthof

Circular polarimetry of gamma-rays - a possible tool for observation of bulk antimatter in the Universe — •Stanislav Tashenov — Physics Institute, Heidelberg University, Germany

A significant body of observations points out that the Universe is composed of matter rather than antimatter. This baryon asymmetry for a long time remains an unsolved problem of physics. The current explanations include a possible CP-symmetry violation or a perfect separation between the bulks of matter and antimatter in the Universe. In the latter case this separation would preclude an observation of annihilation radiation at the border regions. This radiation is currently the only probe for bulk antimatter and it may fail if no bulk matter is present in the vicinity. Another possible method which is free from this limitation is based on circular polarimetry of gamma-rays, in particular on the circular polarization of gamma-ray continuum afterglow which follows a supernova explosion. However, so far no technique to measure circular polarization of cosmic gamma-rays was available. I propose the first such technique which can be naturally integrated into the concept of a gamma-ray Compton telescope. It is based on the transfer of the gamma-ray spin to the recoiled electron in Compton scattering and subsequent detection of the electron spin polarization by means of bremsstrahlung of these electrons. The physics phenomena needed by this technique were recently confirmed and the necessary algorithm for polarization reconstruction was developed.