Nuclear symmetry energy parameters from neutron skin thickness in 208Pb and electric dipole polarizability in 68Ni, 120Sn and 208Pb

Observables like neutron skin thickness and electric dipole polarizability in heavy nuclei are considered as most effective probes for the density dependence of nuclear symmetry energy at subsaturation density region. In the present work, within the framework of droplet model, we use finite range effective interactions to calculate the neutron skin thickness in Pb-208 and the electric dipole polarizability in Ni-68, Sn-120 and Pb-208. We correlate these quantities with the parameters of nuclear symmetry energy. Available experimental data on the neutron skin thickness in Pb-208 and electric dipole polarizability in Ni-68, Sn-120 and Pb-208 are used to deduce information on the density slope parameter of nuclear symmetry energy at saturation and at subsaturation densities. Constraints such as 35.2 <= L(rho(0)) <= 64.4 MeV and 43 <= L(rho(c)) <= 55 MeV are obtained using experimental values for neutron skin thickness.