Observational tests for a class of scalar-tensor gravity

We study observational bounds in a class of scalar-tensor gravity theories recently proposed. Either an upper or lower bound on a conformal factor in these theories is derived from null observation in composition dependent fifth force search, microscope mission. The important case of a lower bound implies that future improved observations have chances of verifying this class of theories. Future prospect for a particular type of observation is mentioned. The considered class of scalar-tensor gravity was shown elsewhere to explain the conversion of inflationary early phase to late time quintessence type dark energy.