About the polarized τ-lepton radiative decay

The polarization effects in the one-meson radiative decay of the polarized [Formula: see text] lepton, [Formula: see text], have been investigated. We present the analytical results for the [Formula: see text]-distribution of the partial differential widths, which are responsible for different polarization phenomena, in the case of the photon energy cut: [Formula: see text]. These quantities depend on the invariant mass squared [Formula: see text] of the pseudoscalar meson and photon and the photon energy cut [Formula: see text] Our analytical formulae, in terms of the weak vector and axial-vector form factors, describing the structure-dependent part of the decay amplitude, are valid also for the decay [Formula: see text] after trivial substitutions of the corresponding constants. We demonstrate the essential decrease of the inner bremsstrahlung contribution in comparison with the structural one with increase of the photon cut energy. In numerical calculations, the vector and axial-vector form factors are determined using the chiral effective theory with resonances (R[Formula: see text]T).

Inner Bremsstrahlung Accompanying the Non-Unique First Forbidden β-Decay of 141Ce

The inner Bremsstrahlung (I.B.) spectrum accompanying the β-decay of 141Ce (non-unique first forbidden β-transition) was measured using a single channel scintillation spectrometer. The measured I.B. was analyzed by the variable width peeling-off method. This analyzed and corrected I.B. was compared with those calculated according to the original theories of Knipp and Uhlenbeck as well as of Bloch (KUB), the coulomb corrected theories of Lewis and Ford and of Nilsson, and according to detour-transition calculations of the Ford and Martin theory. Ths shape correction factor suggested by Konopinski and Uhlenbeck on the Fermi β-decay theory was applied to the calculated I.B. based on Nilsson's theory (modified KUB theory). The experimental results are in better agreement with the modified KUB theory than the other theories.