https://doi.org/10.1051/epjconf/202227403017
Methods on compositeness and related aspects
Departamento de Física, Universidad de Murcia, 30071 Murcia, Spain
* e-mail: oller@um.es
Published online: 22 December 2022
In many physical applications, bound states and/or resonances are observed, which raises the question whether these states are elementary or composite. Here we elaborate on several methods for calculating the compositeness X of bound states and resonances in Quantum Mechanics, and in Quantum Field Theory by introducing particle number operators. For resonances X is typically complex and we discuss how to get meaningful results by using certain phase transformations in the S matrix.
© The Authors, published by EDP Sciences, 2022
This is an Open Access article distributed under the terms of the Creative Commons Attribution License 4.0, which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly cited.
