Angular analysis of bottom-flavored hadron production in semileptonic decays of polarized top quarks

TL;DR

This paper provides a detailed theoretical analysis of bottom-flavored hadron production from polarized top quark decays, incorporating next-to-leading order QCD corrections and fragmentation functions, aiding interpretation of collider measurements.

Contribution

It presents the first analytic differential decay widths at NLO for bottom-hadron production in polarized top decays, using fragmentation functions fitted from $e^+e^-$ data.

Findings

Differential decay widths at parton level derived analytically.

Distributions in bottom-hadron energy for different W-helicities analyzed.

Results support interpretation of top polarization and spin correlation measurements.

Abstract

We study the inclusive production of bottom-flavored hadrons from semileptonic decays of polarized top quarks at next-to-leading order in QCD using fragmentation functions recently determined from a global fit to $e^+e^-$ data. We provide the relevant differential decay widths at parton level in analytic form. These results fill an important gap in the theoretical interpretation of recent measurements of the top-quark polarization and the $t\bar{t}$ spin correlations using dilepton final states in proton-proton collisions at the CERN Large Hadron Collider. As an illustration, we study the distributions in the scaled bottom-hadron energy of the polarized-top-quark decay widths for different $W$-boson helicities.