Texture Specific Mass Matrices and CP violating asymmetry in B^o_d({\bar B}^o_d) -> ψK_S

In the context of texture 4 - zero and texture 5 - zero hierarchical quark mass matrices, CP violating asymmetry in $B^o_d({\bar B}^o_d) \to \psi K_S$ (sin2$\beta$) has been evaluated by considering quark masses at $m_Z$ scale. For a particular viable texture 4 - zero mass matrix the range of sin2\beta is: 0.27 - 0.60 and for the corresponding texture 5 - zero case it is 0.31 - 0.59. Further our calculations reveal a crucial dependence of sin2$\beta$ on light quark masses as well as the phase in this sector.