GLOBAL MONOPOLE IN SCALAR TENSOR THEORY

The well known monopole solution of Barriola and Vilenkin (BV) resulti ng from the breaking of a global SO(3) symmetry is extended in general relativity along with a zero-mass scalar field and also in the Brans- Dicke (BD) theory of gravity. In the case of BD theory, the behaviour of spacetime and other variables such as the BD scalar field and the m onopole energy density have been studied numerically. For a monopole a long with a zero-mass scalar field, exact solutions are obtained and, depending upon the choice of arbitrary parameters, the solutions eithe r reduce to the BV case or to a pure scalar field solution as special cases. It is interesting to note that unlike the BV case the global mo nopole in the BD theory does exert a gravitational pull on a test part icle moving in its spacetime.