Yukawa-type) and gravitational-like (one can get a Poisson equation from it), even within SM, so that Zee's idea was taken 1992 for a scalar–tensor theory with Higgs field as scalar field with Higgs mechanism. There, the massive scalar field couples to the masses, which are at the same time the source of the scalar Higgs field, which generates the mass of the elementary particles through Symmetry Breakdown. For vanishing scalar field, this theories usually go through to standard General Relativity and because of the nature of the massive field, it is possible for such theories that the parameter of the scalar field (the coupling constant) does not have to be as high as in standard JBD theories. Though, it is not clear yet which of these models explains better the phenomenology found in nature nor if such scalar fields are really given or necessary in nature. Nevertheless, JBD theories are used to explain inflation (for massless scalar fields then it is spoken of the inflation field) after the Big Bang as well as the quintessence. Further, they are an option to explain dynamics usually given through the standard cold dark matter models, as well as MOND, Axions (from Breaking of a Symmetry, too), MACHOS,... Connection to string theory A generic prediction of all string theory models is that the spin-2 graviton has a spin-0 partner called the dilaton. Hence, string theory predicts that the actual theory of gravity is a scalar–tensor theory rather than general relativity. However, the precise form of such a theory is not currently known because one does not have the mathematical tools in order to address the corresponding non-perturbative calculations. Besides, the precise effective 4-dimensional form of the theory is also confronted to the so-called landscape issue. Other possible scalar–tensor theories Degenerate Higher-Order Scalar-Tensor theories Theories with non-minimal scalar-matter coupling Dilaton gravity Chameleon theory Pressuron theory References P. Jordan, Schwerkraft und Weltall, Vieweg (Braunschweig) 1955: Projective Relativity. First paper on JBD theories. C.H. Brans and R.H. Dicke, Phys. Rev. 124: 925, 1061: Brans–Dicke theory starting from Mach's principle. R. Wagoner, Phys. Rev. D1(812): 3209, 2004: JBD theories with more than one scalar field. A. Zee, Phys. Rev. Lett. 42(7): 417, 1979: Broken-Symmetric scalar-tensor theory. H. Dehnen and H. Frommert, Int. J. Theor. Phys. 30(7): 985, 1991: Gravitative-like and short-ranged interaction of Higgs fields within the Standard Model or elementary particles. H. Dehnen et al., Int. J.