Geodesic properties and orbits in 5-dimensional hypercylindrical spacetime

We investigate the geodesic motions of a massive particle and a light ray in the hyperplane orthogonal to the symmetry axis in the 5-dimensional hypercylindrical spacetime. The class of the solutions depends on one constant a, which is the ratio of the string mass density to the tension. There exist unstable orbits in a null geodesic only in some range of a. The innermost stable circular orbits in a timelike geodesic also exist only in a certain range of the parameter a. The capture cross-section and the deflection angle of a light ray are also computed.