Anomalous top charged-current contact interactions in single top production at the LHC

TL;DR

This paper investigates anomalous charged-current top quark interactions at the LHC using an effective theory framework, focusing on four-fermion contact interactions and their potential to be distinguished through differential distributions in single top production.

Contribution

It introduces a comprehensive classification of minimal four-fermion contact interactions affecting top quark processes and evaluates their detectability at the LHC using Monte Carlo simulations.

Findings

Next LHC run can set bounds on contact couplings.

Differential distributions enhance coupling discrimination.

Effective theory approach clarifies interaction structures.

Abstract

In an effective theory approach, the full minimal set of leading contributions to anomalous charged-current top couplings comprises various new trilinear tbW as well as quartic tbff' interaction vertices, some of which are related to one another by equations of motion. While much effort in earlier work has gone into the extraction of the trilinear couplings from single top measurements, we argue in this article that these structures can be assessed independently by other observables, while single top production forms a unique window to the four-fermion sector. An effective theory approach is employed to infer and classify the minimal set of such couplings from dimension six operators in the minimal flavor violation scheme. In the phenomenological analysis, we present a Monte Carlo study at detector level to quantify the expected performance of the next LHC run to bound as well as distinguish the various contact couplings. Special attention is directed toward differential final state distributions including detector effects as a means to optimize the signal sensitivity as well as the discriminative power with respect to the possible coupling structures.