The gravitational evidence for dark matt er is well established, and deciphering its microphysical properties is one of the most actively pursued goals in fundamental physics. Despite an overwhelming positive body of evidence, cosmological measurements suggest that there exists an unexpected mass defi cit in small dark matt er halos that host dwarf and low-surface-brightness galaxies. This is not expected in any simple models of dark matt er, but may rather indicate that dark matt er is substantially self-interacting. On the other side, however, no such mass defi cit is observed in much larger halos that host clusters of galaxies, putt ing a principal limit on the strength of such self-interaction, which is tighter than what is required for the small haloes. Xiaoyong Chu and his collaborators solved this conundrum by proposing that the dark matt er self-interaction strongly depends on velocity, through the presence of a resonance. Using a model-independent approach, they show that resonant self-interacting dark matt er can naturally explain the observational data. Dark matt er particles in small haloes generally have low, yet special velocities that make two-body collisions resonant, so that the corresponding cross section is signifi cantly enhanced as compared to the cross section found in clusters of galaxies. This is a novel solution to the mass defi cit problem, and thus opens up a new avenue for self-interacting dark matt er model-building. At last, astrophysical observations with higher precision will be able to test this solution in the future.
DER PREISTRÄGER
Xiaoyong Chu war von 2005–2007 Forschungsassistent an der University of Science and Technolgy of China. Das Masterstudium im Fach Allgemeine Physik hat er 2009 an der Chalmers University of Technology, Schweden, abgeschlossen; 2013 dissertierte er im Fach Theoretische Physik an der Université Libre de Bruxelles, Belgien. Von 2013-2016 hatt e Xiaoyong Chu eine Post-doc-Stelle am International Center for Theoretical Physics in Triest; seit 2016 ist Xiaoyong Chu Postdoc am Institut für Hochenergiephysik der ÖAW.
DER PREIS
Der Best Paper Award (Jubiläumsfonds der Stadt Wien für die ÖAW) in Höhe von 4.000,- Euro wird an wissenschaftliche Mitarbeiterinnen und Mitarbeiter an Forschungseinrichtungen der mathematisch-naturwissenschaftlichen Klasse der ÖAW für die beste wissenschaftliche Arbeit – Monographie oder Originalartikel – vergeben, die im Jahr vor dem Einreichtermin in einem Verlag bzw. einer Fachzeitschrift mit Peer-Review-System publiziert oder zur Publikation akzeptiert wurde.
Foto: Copyright ÖAW_Daniel Hinterramskogler