Neutron stars in the scalar-tensor theory of gravitation

We have several theories of gravitation other than Einstein's theory of general reiativity. Distinction among these theories might be possible from the study of superdense objects. The best-studied superdense object is the so-called neutron star. Its mass, radius and other properties can be determined from the equation of state for the stellar matter and the theory of gravitation. Although the general relativity has been mainly used as the theory of gravitation, Salmona1> applied· the scalar-tensor theory of Brans and Dicke.2> In his calculation he assumed the equation of state for a noninteracting Fermi gas neglecting the effects of nuclear forces. In this letter we take into account the nuclear forces using the Kodama-Yamada mass formula for compressible nuclei. 8> As for the model of neutron star we assume, for simplicity, that the star is static and spherically symmetric. We also assume that the star is composed of neutrons only. Then, the energy density e is written as