We study asymptotic safety of models of the higher derivative quantum gravity
with and without matter. The beta functions are derived by utilizing the
functional renormalization group, and non-trivial fixed points are found. It
turns out that all couplings in gravity sector, namely the cosmological
constant, the Newton constant, and the R2 and Rμν2 coupling
constants, are relevant in case of higher derivative pure gravity. For the
Higgs-Yukawa model non-minimal coupled with higher derivative gravity, we find
a stable fixed point at which the scalar-quartic and the Yukawa coupling
constants become relevant. The relevant Yukawa coupling is crucial to realize
the finite value of the Yukawa coupling constants in the standard model.Comment: Version published in JHEP; 75 pages, 10 figures, typos corrected,
references adde