Final-state interactions andCPviolation in weak decays

The $\mathrm{CP}$-violating difference between the partial decay rates of a particle and antiparticle depends on final-state interactions. A general formalism is presented for calculating this difference based on $\mathrm{CPT}$ invariance and unitarity. Applications are given to $B$ decays and the formalism is compared to the standard method using penguin graphs.