Evidence for dynamical chiral condensate in high-energy heavy ion collisions

Fuente: arXiv
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Main Authors: Bruschke, Tobias, Kirchner, Andreas, Floerchinger, Stefan
Format: Preprint
Published: 2025
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author Bruschke, Tobias
Kirchner, Andreas
Floerchinger, Stefan
author_facet Bruschke, Tobias
Kirchner, Andreas
Floerchinger, Stefan
contents Quantum chromodynamics with light quarks features an approximate global symmetry, known as chiral symmetry, that is believed to be spontaneously broken by the vacuum expectation value of a scalar and isoscalar composite field, in addition to a small explicit breaking due to finite quark masses. For a high enough temperature, as achieved in the early universe or the fireball created by a high-energy heavy ion collision, this symmetry is expected to be restored. We show theoretically that a coherent deviation of the corresponding quantum field from its usual vacuum expectation value on the freeze-out hypersurface of a heavy-ion collision leads, after resonance decays, to a characteristic contribution to the transverse momentum spectrum of charged pions, in the very soft regime, consistent with experimental data from the Relativistic Heavy Ion Collider and the Large Hadron Collider. Taken together, the experimental data with the new theoretical results provide compelling support for the existence of a chiral condensation mechanism with partial restoration of chiral symmetry at high temperature.
format Preprint
id arxiv_https___arxiv_org_abs_2512_17413
institution arXiv
publishDate 2025
record_format arxiv
spellingShingle Evidence for dynamical chiral condensate in high-energy heavy ion collisions
Bruschke, Tobias
Kirchner, Andreas
Floerchinger, Stefan
High Energy Physics - Phenomenology
Nuclear Theory
Quantum chromodynamics with light quarks features an approximate global symmetry, known as chiral symmetry, that is believed to be spontaneously broken by the vacuum expectation value of a scalar and isoscalar composite field, in addition to a small explicit breaking due to finite quark masses. For a high enough temperature, as achieved in the early universe or the fireball created by a high-energy heavy ion collision, this symmetry is expected to be restored. We show theoretically that a coherent deviation of the corresponding quantum field from its usual vacuum expectation value on the freeze-out hypersurface of a heavy-ion collision leads, after resonance decays, to a characteristic contribution to the transverse momentum spectrum of charged pions, in the very soft regime, consistent with experimental data from the Relativistic Heavy Ion Collider and the Large Hadron Collider. Taken together, the experimental data with the new theoretical results provide compelling support for the existence of a chiral condensation mechanism with partial restoration of chiral symmetry at high temperature.
title Evidence for dynamical chiral condensate in high-energy heavy ion collisions
topic High Energy Physics - Phenomenology
Nuclear Theory
url https://arxiv.org/abs/2512.17413