Odd-even staggerings exhibited in nuclear masses

The description of nuclear masses is one fundamental issue in nuclear structure theory. A number of odd-even staggerings of masses have been observed in double differences of neighboring nuclei. These odd-even staggerings are very useful to study local mass relations and nucleon-pair correlations. In this paper we discuss the odd-even features that we discerned in recent years, such as the odd-even staggering of the interaction between the last proton and the last neutron (denoted by δV_1p-1n), the odd-even feature of the Garvey-Kelson mass relations, the odd-even feature of one-nucleon separation energies, and so on, exhibited in masses of neighboring nuclei and related quantities. (author)