$F(R)$ gravity inflationary model with $(R+R_0)^{3/2}$ term

The proposed inflationary model, which is a one-parametric generalization of the Starobinsky $R+R^2$ model, includes the $(R+3m^2\beta^2)^{3/2}$ term, where the parameter $m$ is the inflaton mass, defined in the same way as in the Starobinsky model, and $\beta$ is a dimensionless constant. Using the conformal transformation and the Einstein frame potential, we obtain the inflationary parameters of the model proposed. The value of the tensor-to-scalar ratio $r$ is bigger than in the Starobinsky model. The considered inflationary model produces a good fit to current observation data.Comment: 11 pages, 2 figure