Neutrino masses and lepton mixing from $A_5\times{\rm CP}$

We analyse in detail the phenomenological implications for lepton masses and mixing derived by the breaking of the discrete symmetries $A_5 \times CP$ into the subgroups $Z_2 \times CP$ in the neutrino sector and $Z_5$ in the charged lepton sector. We derive accurate analytic expressions for the sum of the neutrino masses $\Sigma_i m_i$ as well as for the effective Majorana masses $m_\beta$ and $m_{\beta \beta}$ under different hypotheses for the flavon vevs and compare them with the exact numerical results obtained from the diagonalization of the neutrino mass matrix.