Topped baryons from QCD sum rules

TL;DR

This paper uses QCD sum rules within heavy quark effective theory to predict the masses of ground-state singly topped baryons, providing a nonperturbative perspective on top quark bound states.

Contribution

It introduces a novel nonperturbative analysis of singly topped baryons using QCD sum rules and heavy quark effective theory, estimating their masses around 174 GeV.

Findings

Masses of singly topped baryons are around 174 GeV.

Singly topped baryons are predicted to be about 1.1-1.5 GeV heavier than the top quark.

The study offers a complementary approach to toponium analysis.

Abstract

The recent CMS observation of a near-threshold enhancement in top quark pair production provides the first experimental indication of a short-lived pseudoscalar $t\bar{t}$ bound state, commonly referred to as toponium. While most existing studies focus on toponium using perturbative QCD near threshold, baryonic configurations containing a single top quark -- singly topped baryons -- offer a complementary nonperturbative perspective. Notably, singly topped baryons are expected to exhibit a longer lifetime and a narrower decay width than toponium, since only one top quark decays rather than two. The heavy quark effective theory provides a natural and powerful framework for analyzing such systems, allowing the separation of heavy and light quark dynamics. In this work we employ heavy quark effective theory to investigate the internal structure of ground-state singly topped baryons. We construct their interpolating currents and analyze them using QCD sum rules. The resulting masses of the ground-state singly topped baryons are found to lie around 174 GeV, approximately $1.1$-$1.5$ GeV above the pole mass of the top quark.