A new XENON100 analysis, published in Science this week, refutes a long-standing claim of dark matter detection. Dark matter is an abundant but unseen matter in the universe considered largely responsible for the gravitational force that keeps the Milky Way galaxy together. According to most current theoretical models, the hypothetical dark matter particles interact with atomic nuclei. However, such interactions have not been detected to date. The scientists of the XENON collaboration have developed novel analysis techniques to search for the first time in the data of the XENON100 detector for interactions of dark matter with electrons of the atomic shell. The analysis did not yield any signal above the very low background, further constraining the properties of dark matter.
The mass of an atomic nucleus is equal to the mass of its anti-particle, the anti-nucleus. This has recently been proven by tens of millions of unprecedentedly accurate measurements by ALICE, one of the experiments being conducted on CERN's LHC particle accelerator. A tiny difference in mass would be an indication of a violation of fundamental symmetry, which would in turn be a possible clue as to why our universe contains almost no antimatter, despite the fact that an equal amount of matter and antimatter should have been formed during the 'big bang'. "The mystery of the missing antimatter still hasn't been solved, but our results bring us a step further", says FOM workgroup leader Thomas Peitzmann from Utrecht University. The results of their research were published this week in Nature Physics.
Researchers of the MESA+ Institute for Nanotechnology of the University of Twente and the FOM Foundation have discovered an unusual magnetic effect in nanolayers of an oxide of lanthanum and manganese (LaMnO3
). Joint work with colleagues from Singapore, the United States and Ireland revealed an abrupt magnetic transition brought about by the slightest change in thickness of the layer. Science
magazine published the research findings this week.