Motivated by the 2.8σ discrepancy observed between the BABAR measurement and the standard model prediction of the CP asymmetry in τ→KSπντ decays, as well as the prospects of future measurements at Belle II, we revisit this observable in this paper. Firstly, we reproduce the known CP asymmetry due to K0−K¯0 mixing by means of the reciprocal basis, which is convenient when a KS(L) is involved in the final state. As the Kπ tensor form factor plays a crucial role in generating a nonzero direct CP asymmetry that can arise only from the inte...
