What is the right formalism to search for resonances? II. The pentaquark chain

A. Pilloni; J. Nys; M. Mikhasenko; M. Albaladejo; C. Fernández-Ramírez; A. Jackura; V. Mathieu; N. Sherrill; T. Skwarnicki; A. P. Szczepaniak

doi:10.1140/epjc/s10052-018-6177-2

EPJ

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2023 Impact factor 4.2

Particles and Fields

Open Access

Eur. Phys. J. C (2018) 78: 727
https://doi.org/10.1140/epjc/s10052-018-6177-2

Special Article - Tools for Experiment and Theory

Joint Physics Analysis Center

A. Pilloni¹^*, J. Nys¹^,2^,3^,4, M. Mikhasenko⁵, M. Albaladejo⁶, C. Fernández-Ramírez⁷, A. Jackura³^,4, V. Mathieu¹, N. Sherrill³^,4, T. Skwarnicki⁸ and A. P. Szczepaniak¹^,3^,4

¹ Theory Center, Thomas Jefferson National Accelerator Facility, Newport News, VA, 23606, USA
² Department of Physics and Astronomy, Ghent University, 9000, Ghent, Belgium
³ Center for Exploration of Energy and Matter, Indiana University, Bloomington, IN, 47403, USA
⁴ Physics Department, Indiana University, Bloomington, IN, 47405, USA
⁵ Helmholtz-Institut für Strahlen- und Kernphysik, Universität Bonn, 53115, Bonn, Germany
⁶ Departamento de Física, Universidad de Murcia, 30071, Murcia, Spain
⁷ Instituto de Ciencias Nucleares, Universidad Nacional Autónoma de México, 04510, Mexico City, Mexico
⁸ Syracuse University, Syracuse, NY, 13244, USA

^* e-mail: pillaus@jlab.org

Received: 28 June 2018
Accepted: 23 August 2018
Published online: 8 September 2018

Abstract

We discuss the differences between several partial-wave analysis formalisms used in the construction of three-body decay amplitudes involving fermions. Specifically, we consider the decay , where the hidden charm pentaquark signal has been reported. We analyze the analytical properties of the amplitudes and separate kinematical and dynamical singularities. The result is an amplitude with the minimal energy dependence compatible with the S-matrix principles.