We present detailed calculations about the expected shape of two-pion Bose-Einstein [or Hanbury-Brown–Twiss (HBT)] correlations in high energy heavy ion collisions that include a realistic treatment of final state Coulomb interaction as well as strong interactions (dominated by $s$-wave scattering). We assume Lévy type source functions, a generalization that goes beyond the Gaussian approximation. Various recent experimental results found the use of such source types necessary to properly describe the shape of the measured correlation functions. We find that strong interaction effects for like-sign pions are small, but their consideration may become important in future precision measurements, especially if one considers source parameters beyond the Gaussian HBT radii. Precise experimental determination of these source parameters (such as Lévy stability exponent, correlation strength, etc.) may then benefit from the inclusion of the treatment of strong interaction not just for heavier particles (e.g., protons, $\mathrm{\Lambda }\mathrm{s}$) but also in case of two-pion measurements.

• Received 10 February 2020
• Revised 20 October 2020
• Accepted 7 December 2020

DOI:https://doi.org/10.1103/PhysRevC.102.064912

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Published by the American Physical Society