Strange fireball as an explanation of the muon excess in Auger data

2016/12/31 by Luis A. Anchordoqui, Haim Goldberg, T. Weiler +1 · 49 citations
Physics and Astronomy · #Astrophysics and Cosmic Phenomena #Baryon #Gluon #Hadron #Hadronization #High-Energy Particle Collisions Research #Muon #Nuclear physics #Particle physics #Particle physics theoretical and experimental studies #Physics #Pion #Quark #Quark–gluon plasma #Strange quark #Strangeness #astro-ph.HE #hep-ph

paper · pdf · doi:10.1103/physrevd.95.063005

published in Physical review. D/Physical review. D. 95(6) (American Physical Society) · To be published in PRD

openalex publication_date 2017/03/06 · arxiv created 2019/08/03 · arxiv updated 2019/08/06 · openalex created_date 2025/10/10 · openalex updated_date 2026/08/06

Abstract

We argue that ultrahigh-energy cosmic-ray collisions in Earth's atmosphere can probe the strange quark density of the nucleon. These collisions have center-of-mass energies \ensuremath\gtrsim10^4.6A GeV, where A\ensuremath≥14 is the nuclear baryon number. We hypothesize the formation of a deconfined thermal fireball which undergoes a sudden hadronization. At production the fireball has a very high matter density and consists of gluons and two flavors of light quarks (u, d). Because the fireball is formed in the baryon-rich projectile fragmentation region, the high baryochemical potential damps the production of uu and dd pairs, resulting in gluon fragmentation mainly into ss. The strange quarks then become much more abundant and upon hadronization the relative density of strange hadrons is significantly enhanced over that resulting from a hadron gas. Assuming the momentum distribution functions can be approximated by Fermi-Dirac and Bose-Einstein statistics, we estimate a kaon-to-pion ratio of about 3 and expect a similar (total) baryon-to-pion ratio. We show that, if this were the case, the excess of strange hadrons would suppress the fraction of energy which is transferred to decaying \ensuremathπ⁰'s by about 20%, yielding an \ensuremath∼40% enhancement of the muon content in atmospheric cascades, in agreement with recent data reported by the Pierre Auger Collaboration.

Citations

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