Direct mass measurements of neutron-deficient xenon isotopes using the ISOLTRAP mass spectrometer

The masses of the noble-gas Xe isotopes with 114 $\leq$ A $\leq$ 123 have been directly measured for the first time. The experiments were carried out with the ISOLTRAP triple trap spectrometer at the online mass separator ISOLDE/CERN. A mass resolving power of the Penning trap spectrometer of $m/\Delta m$ of close to a million was chosen resulting in an accuracy of $\delta m \leq 13$ keV for all investigated isotopes. Conflicts with existing, indirectly obtained, mass data by several standard deviations were found and are discussed. An atomic mass evaluation has been performed and the results are compared to information from laser spectroscopy experiments and to recent calculations employing an interacting boson model.