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 1 GeV scale as well as at $m_Z$ scale. For a particular texture 4 - zero mass matrix, which fairly reproduces PDG CKM matrix, the range of sin2\beta is: 0.39 - 0.54 (1 GeV) and 0.27 - 0.61 ($m_z$), for the texture 5 - zero case it is 0.45 - 0.54 (1 GeV) and 0.31 - 0.58 ($m_Z)$. Further our calculations reveal a crucial dependence of sin2\beta on light quark masses as well as the phase in this sector.