The decay (B) over bar (0) --> pi(+)pi(-)gamma has a bremsstrablung component determined by the amplitude for (B) over bar (0) --> pi(+)pi(-) , as well as a direct component determined by the penguin interaction V(tb)V(tb)(*)c(7)O(7). Interference of these amplitudes produces a photon energy spectrum dGamma/dx = a/x + b + c(1)x + c(2)x(2) + ... (x =2E(gamma)/m(B)) where the terms c 1,2 contain a dependence on the phase alpha(eff) = pi - arg(VtbVtd*)*A((B) over bar (0) --> pi(+)pi(-)). We also examine the angular distribution of these decays, and show that in the presence of strong phases, an untagged B-0/(B) over bar (0) beam can exhibit an asymmetry between the pi(+) and pi(-) energy spectra. (C) 2002 Elsevier Science B.V. All rights reserved. References: 15
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