0000000000970237
AUTHOR
M. C. Mauser
Complete angular analysis of polarized top quark decay atO(αs)
We calculate the O(alpha_s) radiative corrections to the three spin independent and five spin dependent structure functions that describe the angular decay distribution in the decay of a polarized top quark into a W-boson (followed by the decay W^{+} -> l^{+} + nu_l or by W^{+} -> anti-q + q and a bottom quark. The angular decay distribution is described in cascade fashion, i.e. the decay t(uparrow) -> W^{+} + X_b is analyzed in the top rest system while the subsequent decay W^{+} -> l^{+} + nu_l (or W^{+} -> anti-q + q) is analyzed in the W rest frame. We present our results for the eight O(alpha_s) integrated structure functions in analytical form keeping the mass of the bottom quark fini…
Inclusive decays of B mesons into Ds and at O(αs) including polarization effects
The dominant contribution to the inclusive decays of B mesons into the charm-strangeness mesons Ds and Ds∗ is expected to be given by the partonic process b→c+(Ds−,Ds∗−). We determine the nonperturbative O(1/mb2) and the O(αs) radiative corrections to b→c+(Ds−,Ds∗−) and thereby to the inclusive decays B→Xc+(Ds−,Ds∗−). The new feature of our calculation is that we separately determine the nonperturbative and the O(αs) corrections to the longitudinal (L) and transverse (T) pieces of the spin 1 Ds∗− meson. The longitudinal/transverse composition of the Ds∗− can be probed through its two principal decay modes Ds∗−→Ds−+γand Ds∗−→Ds−+π0 for which we write down the angular decay distributions.
Leptonicμandτdecays: Mass effects, polarization effects, andO(α)radiative corrections
We calculate the radiative corrections to the unpolarized and the four polarized spectrum and rate functions in the leptonic decay of a polarizedinto a polarized electron. The new feature of our calculation is that we keep the mass of the final state electron finite which is mandatory if one wants to investigate the threshold region of the decay. Analytical results are given for the energy spectrum and the polar angle distribution of the final state electron whose longitudinal and transverse polarization is calculated. We also provide analytical results on the integrated spec- trum functions. We analyze the me → 0 limit of our general results and investigate the quality of the me → 0 approx…
Electroweak and finite width corrections to top quark decays into transverse and longitudinal $ W $-bosons
We calculate the electroweak and finite width corrections to the decay of an unpolarized top quark into a bottom quark and a $ W $-gauge boson where the helicities of the $ W $ are specified as longitudinal, transverse-plus and transverse-minus. Together with the $ O(\alpha_s) $ corrections these corrections may become relevant for the determination of the mass of the top quark through angular decay measurements.
Longitudinal, transverse-plus and transverse-minus W-bosons in unpolarized top quark decays at O(alpha_s)
We consider the O(alpha_s) radiative corrections to the decay of an unpolarized top quark into a bottom quark and a W-gauge boson where the helicities of the W are specified as longitudinal, transverse-plus and transverse-minus. The O(alpha_s) radiative corrections lower the normalized longitudinal rate Gamma_L/Gamma by 1.06% and increase the the normalized transverse-minus rate Gamma_-/Gamma by 2.17%. We find that the normalized transverse-plus rate Gamma_+/Gamma, which vanishes at the Born term level for m_b->0, receives radiative correction contributions at the sub-percent level. We discuss m_b!=0 effects for the Born term and the alpha_s-contributions but find these to be small. Our …