U-spin analysis of CP violation in B− decays into three charged light pseudoscalar mesons

We carry out a U-spin symmetry analysis for CP violation in B− decays into three light π−π−π+, π−K−K+, K−K−K+ and K−π−π+ mesons. We clarify some subtle points in constructing decay amplitudes with U=0 formed by the two negatively charged light mesons in the final states. U-spin conserving momentum independent and momentum dependent decay amplitudes, and U-spin violating decay amplitudes due to quark mass difference are constructed.