New constraint on squark flavor mixing from ¹⁹⁹Hg electric dipole moment

A new constraint is obtained on the CP-violating flavor mixing between the left-handed top scalar quark (t̃_L) and charm scalar quark (c̃_L), by considering a chargino loop contribution to chromo-electric dipole moment of strange quark, which is limited by the electric dipole moment of the ¹⁹⁹Hg atom. It is found that the flavor mixing should be suppressed to the level of O(0.1) for the CP phase of order unity, when tanβ is relatively large and sparticle masses lie in a few hundred GeV range. Although it is much stronger than the known constraint from the chargino loop contribution to b→sγ, the moderate constraint we obtain here is argued to leave room for sizable supersymmetric contribution to the CP asymmetry in B_d⁰→φK_s.