Document Type

Article

Publication Date

2024

DOI

10.1103/PhysRevD.110.026017

Publication Title

Physical Review D

Volume

110

Issue

2

Pages

026017 (1-28)

Abstract

We discuss how the quark masses and their mass splitting affect the baryons in the Skyrme model as well as the Witten-Sakai-Sugimoto (WSS) model. In both cases, baryons are described by solitonic objects, i.e., Skyrmions and instantons, respectively. After the quantization of their zero modes, the nucleons become quantum states of a rotor. We show how the quark mass affects the moment of inertia and we provide a semianalytic approach valid in the small-mass limit. Additionally, we show how the two lightest quarks’ mass splitting affects the moments of inertia of the Skyrmion and induces an isospin breaking effect. This effect turns out not to be enough to split the degeneracy in the neutron-proton multiplet, but it splits some of the states in the Δ multiplet. Unlike the basic Skyrme model, the WSS model already includes vector mesons and another mechanism to transfer isospin breaking from quark masses to the solitons is known. We compute the splitting of the moment of inertia in the small-mass limit in the WSS model and combine the two effects on the spectrum of baryons, in particular the Δ’s.

Rights

© 2024 The Authors.

Published under the terms of the Creative Commons Attribution 4.0 International (CC BY 4.0) License. Further distributions of this work must maintain attribution to the authors and the published article's title, journal citation, and DOI. Funded by SCOAP3.

Original Publication Citation

Bartolini, L., Bolognesi, S., Gudnason, S. B., & Rainaldi, T. (2024). Mass and isospin breaking effects in the Skyrme model and in holographic QCD. Physical Review D, 110(2), 1-28, Article 026017. https://doi.org/10.1103/PhysRevD.110.026017

ORCID

0000-0002-8342-6765 (Rainaldi)

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