ELEMENTARY PARTICLES AND FIELDS Theory Model-Independent Analysis of B → B → B → π + - Decays

for the decays B → π� + � − (� ± = e ± ,μ ± ) and the invariant-mass spectrum of dileptons for the process B + → π + � + � − are presented. The resulting theoretical estimates depend on the choice of model for the B → π transition form factors f+(q 2 ), f0(q 2 ) ,a ndfT (q 2 ). However, one can get rid of this arbitrariness by employing experimental data or the results of QCD lattice calculations to determine the parameter dependence of the form factors. Data from B-meson factories were used to determine the dependence of the form factor f+(q 2 ) on the transfer momentum squared. Yet another required form factor, fT (q 2 ) ,w as extracted from available lattice data on B → π and B → K transitions with allowance for nearly identical effects of the breakdown of flavor SU(3)F symmetry in the respective form factors. The resulting value of the decay branching fraction, B(B + → π + μ + μ − )= 1.88 +0.32 −0.21 × 10 −8 , is in good agreement with the results of measurements of the LHCb Collaboration. The branching fraction for the isospin analog of the decay under consideration is B(B 0 → π 0 μ + μ − )= 0.94 +0.16 −0.11 × 10 −8 . Therefore, this decay can be measured at the Super-B factory under construction.