Heavy Scalar Top Quark Decays in the Complex MSSM: A Full One-Loop Analysis

TL;DR

This paper provides a comprehensive one-loop level analysis of heavy scalar top quark decays in the complex MSSM, including all decay channels and radiative corrections, crucial for accurate predictions at colliders.

Contribution

It presents the first full one-loop calculation of all decay modes of the heavy scalar top quark in the complex MSSM, including detailed renormalization and radiation effects.

Findings

Partial decay widths can differ from tree-level by up to 30%.

Decay branching ratios are significantly affected by loop corrections.

Results are essential for interpreting collider data on scalar top quarks.

Abstract

We evaluate all two-body decay modes of the heavy scalar top quark in the Minimal Supersymmetric Standard Model with complex parameters (cMSSM) and no generation mixing. The evaluation is based on a full one-loop calculation of all decay channels, also including hard QED and QCD radiation. The renormalization of the complex parameters is described in detail. The dependence of the heavy scalar top quark decay on the relevant cMSSM parameters is analyzed numerically, including also the decay to Higgs bosons and another scalar quark or to a top quark and the lightest neutralino. We find sizable contributions to many partial decay widths and branching ratios. They are roughly of O(10%) of the tree-level results, but can go up to 30% or higher. These contributions are important for the correct interpretation of scalar top quark decays at the LHC and, if kinematically allowed, at the ILC. The evaluation of the branching ratios of the heavy scalar top quark will be implemented into the Fortran code FeynHiggs.