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  • Open Access

Explaining Snowball-in-Hell Phenomena in Heavy-Ion Collisions Using a Novel Thermodynamic Variable

Eric Braaten1,*, Kevin Ingles1,2,†, and Justin Pickett1,‡

  • *Contact author: braaten.1@osu.edu
  • †Contact author: ingles.27@osu.edu
  • ‡Contact author: pickett.158@buckeyemail.osu.edu
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Phys. Rev. Lett. 134, 252301 – Published 26 June, 2025

DOI: https://doi.org/10.1103/7cjr-fgdw

Abstract

A loosely bound hadronic molecule produced by a relativistic heavy-ion collision has been described as a “snowball in hell” since it emerges from a hadron resonance gas whose temperature is orders of magnitude larger than the binding energy of the molecule. This remarkable phenomenon can be explained in terms of a novel thermodynamic variable called the “contact” that is conjugate to the binding momentum of the molecule. The production rate of the molecule can be expressed in terms of the contact density at the kinetic freeze-out of the hadron resonance gas. It approaches a nonzero limit as the binding energy goes to 0.

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Outline

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Phys. Rev. Lett. 134, 252301– Published 26 June, 2025
  • Received 8 August 2024
  • Revised 8 March 2025
  • Accepted 22 May 2025
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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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