Abstract
The study of the strength and behavior of the antikaon-nucleon () interaction constitutes one of the key focuses of the strangeness sector in low-energy quantum chromodynamics (QCD). In this Letter a unique high-precision measurement of the strong interaction between kaons and protons, close and above the kinematic threshold, is presented. The femtoscopic measurements of the correlation function at low pair-frame relative momentum of () and () pairs measured in collisions at , 7, and 13 TeV are reported. A structure observed around a relative momentum of in the measured correlation function of () with a significance of constitutes the first experimental evidence for the opening of the isospin breaking channel due to the mass difference between charged and neutral kaons. The measured correlation functions have been compared to Jülich and Kyoto models in addition to the Coulomb potential. The high-precision data at low relative momenta presented in this work prove femtoscopy to be a powerful complementary tool to scattering experiments and provide new constraints above the threshold for low-energy QCD chiral models.
- Received 18 July 2019
- Revised 3 December 2019
- Accepted 11 February 2020
DOI:https://doi.org/10.1103/PhysRevLett.124.092301
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.
© 2020 CERN, for the ALICE Collaboration