Refined analysis and updated constraints on general non-standard tbW couplings

Abstract

We recently studied possible non-standard tbW couplings based on the effective-Lagrangian which consists of four kinds of SU(3)×SU(2)×U(1) invariant dimension-6 effective operators and gave an experimentally allowed region for each non-standard coupling. We here re-perform that analysis much more precisely based on the same experimental data but on a new computational procedure using the Graphics-Processing-Unit (GPU) calculation system. Comparing these two analyses with each other, the previous one is found to have given quite reliable results despite of its limited computation capability. We then apply this new procedure to the latest data and present updated results.

Keywords

• Top decay
• Anomalous top couplings
• Effective-Lagrangian approach