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  • Open Access

Entanglement in elastic and inelastic two-particle scatterings at high energy

Robi Peschanski*

Shigenori Seki†

  • Institute for Fundamental Sciences, Setsunan University, 17-8 Ikedanaka-machi, Neyagawa, Osaka 572-8508, Japan

  • *Contact author: robi.peschanski@ipht.fr
  • †Contact author: shigenori.seki@setsunan.ac.jp
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Phys. Rev. D 113, 105023 – Published 26 May, 2026

DOI: https://doi.org/10.1103/h7dq-yzm6

Abstract

We study the entanglement produced in transverse momentum by two-particle scattering at high energy. Employing the S-matrix framework for the derivation of reduced density matrices, we formulate the entanglement entropy for an inelastic scattering as well as an elastic one. We display the formulas of the entanglement entropy in terms of two-body cross sections. We also derive the entanglement density as a function of the transverse momentum. As an application, we then focus on both forward elastic (pn→pn) and inelastic (pn→np) channels scattering allowing for a fruitful comparison of the two reactions with the same proton-neutron content. We evaluate the elastic and inelastic entanglement entropy by using known parametrizations of experimental data for neutron-proton reactions. Comparing those entanglement entropies, we observe that the inelastic scattering produces more overall entanglement than the elastic one in the pn sector.

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Phys. Rev. D 113, 105023– Published 26 May, 2026
  • Received 9 February 2026
  • Accepted 9 April 2026
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Published by the American Physical Society under the terms of the Creative Commons Attribution 4.0 International license. Further distribution of this work must maintain attribution to the author(s) and the published article’s title, journal citation, and DOI. Funded by SCOAP3.

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