[Paper Review] Radiative corrections to top quark decay into charged Higgs at the Tevatron

J. A. Coarasa, Jaume Guasch+1 more|ArXiv.org|Mar 1, 1999

Particle physics theoretical and experimental studies5 citations

TL;DR

This paper computes leading one-loop electroweak radiative corrections to the top quark decay width into a charged Higgs boson (t → H⁺b) at the Tevatron, using a physically motivated tan(β) definition. It finds large corrections in both the MSSM and 2HDM, significantly impacting the interpretation of Tevatron data and eliminating model-independent bounds in the tan(β)–MH⁺ plane.

ABSTRACT

We present the computation of the leading one-loop electroweak radiative corrections to the non-standard top quark decay width Gamma(t->H+ b), using a physically motivated definition of tan(beta). We find that the corrections are large, both in the Minimal Supersymmetric Standard Model (MSSM) and the Two-Higgs-Doublet Model (2HDM). These corrections have an important effect on the interpretation of the Tevatron data, leading to the non-existence of a model-independent bound in the tan(beta)-MH+ plane.

Motivation & Objective

• To compute one-loop electroweak radiative corrections to the top quark decay width Γ(t → H⁺b) at the Tevatron.
• To assess the impact of these corrections on the interpretation of experimental data from the Tevatron.
• To examine how the choice of tan(β) definition affects the results in the context of the MSSM and 2HDM.
• To determine whether model-independent bounds can be established in the tan(β)–MH⁺ parameter plane.
• To evaluate the significance of radiative corrections for the discovery potential of charged Higgs bosons.

Proposed method

• Performs a one-loop electroweak calculation of the decay width Γ(t → H⁺b) in the context of the MSSM and 2HDM.
• Applies a physically motivated definition of tan(β) to ensure consistency with the underlying model parameters.
• Uses standard renormalization procedures and loop integrals to compute quantum corrections.
• Considers dominant contributions from W, Z, and charged Higgs boson exchanges in the loop diagrams.
• Evaluates the sensitivity of the results to the charged Higgs mass (MH⁺) and tan(β) values.
• Compares the corrected decay width to the tree-level prediction to quantify the size of radiative effects.

Experimental results

Research questions

• RQ1 How large are the one-loop electroweak radiative corrections to the top quark decay width into a charged Higgs boson?
• RQ2 What is the impact of these corrections on the interpretation of Tevatron data for charged Higgs searches?
• RQ3 Does the use of a physically motivated tan(β) definition alter the significance of the radiative corrections?
• RQ4 Can a model-independent bound be established in the tan(β)–MH⁺ plane after including radiative corrections?
• RQ5 How do the corrections differ between the MSSM and the 2HDM in the context of top quark decays?

Key findings

• The one-loop electroweak radiative corrections to Γ(t → H⁺b) are found to be large in both the MSSM and the 2HDM.
• These large corrections significantly alter the decay width predictions, invalidating simple tree-level estimates.
• The corrections have a strong dependence on both tan(β) and the charged Higgs mass MH⁺.
• As a result, no model-independent bound can be established in the tan(β)–MH⁺ plane due to the size and structure of the radiative corrections.
• The physical definition of tan(β) used in the calculation ensures consistency and improves the reliability of the results.
• The findings imply that radiative corrections must be included in any precise analysis of top quark decays involving charged Higgs bosons at the Tevatron.