Evidence for a long-lived superheavy nucleus with atomic mass number A=292 and atomic number Z= 122 in natural Th

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Evidence for the existence of a superheavy nucleus with atomic mass number A=292 and abundance (1-10)x10(-12) relative to 232Th has been found in a study of natural Th using inductively coupled plasma-sector field mass spectrometry. The measured mass matches the predictions [1,2] for the mass of an isotope with atomic number Z=122 or a nearby element. Its estimated half-life of t1/2 >= 10⁸ y suggests that a long-lived isomeric state exists in this isotope. The possibility that it might belong to a new class of long-lived high spin super- and hyperdeformed isomeric states is discussed.[3-6]