QCD angular momentum in $N \rightarrow \Delta$ transitions

TL;DR

This paper explores the QCD angular momentum in nucleon to delta transitions, linking theoretical calculations with experimental observables to better understand the flavor asymmetry in nucleon structure.

Contribution

It extends the concept of QCD angular momentum to baryon transitions, connecting theoretical models with lattice QCD and experimental GPD measurements.

Findings

Calculated transition angular momentum using 1/N_c expansion.

Connected transition AM with flavor asymmetry in nucleons.

Proposed experimental methods to measure transition GPDs.

Abstract

$N \rightarrow \Delta$ transitions offer new possibilities for exploring the isovector component of the QCD quark angular momentum (AM) operator causing the $J^{u - d}$ flavor asymmetry in the nucleon. We extend the concept of QCD AM to transitions between baryon states, using light-front densities of the energy-momentum tensor in transversely localized states. We calculate the $N \rightarrow \Delta$ transition AM in the $1/N_c$ expansion, connect it with the $J^{u - d}$ flavor asymmetry in the nucleon, and estimate the values using lattice QCD results. In the same setup we connect the transition AM to the transition GPDs sampled in hard exclusive electroproduction processes with $N \rightarrow \Delta$ transitions, enabling experimental study of the transition AM.