Spin-dependent energy distribution of B-hadrons from polarized top decays considering the azimuthal correlation rate

摘要

Basically, the energy distribution of bottom-flavored hadrons produced through polarized top quark decays t ( ↑ ) → W + + b ( → X b ) , is governed by the unpolarized rate and the polar and the azimuthal correlation functions which are related to the density matrix elements of the decay t ( ↑ ) → b W + . Here we present, for the first time, the analytical expressions for the O ( α s ) radiative corrections to the differential azimuthal decay rates of the partonic process t ( ↑ ) → b + W + in two helicity systems, which are needed to study the azimuthal distribution of the energy spectrum of the hadrons produced in polarized top decays. These spin-momentum correlations between the top quark spin and its decay product momenta will allow the detailed studies of the top decay mechanism. Our predictions of the hadron energy distributions also enable us to deepen our knowledge of the hadronization process and to test the universality and scaling violations of the bottom-flavored meson fragmentation functions.