Testing strong isospin breaking effects in QCD thermodynamics
Abstract
Most modern lattice QCD calculations take the masses of the light quarks to be degenerate, setting mu=md, a choice that, while not physical, increases computational efficiency and lowers the complexity of simulations and analysis. For many observables, the systematic error associated with this simplification is expected to be negligible, as Δmud=md−mu is significantly below the QCD scale. So far lattice studies have examined the role of strong isospin breaking (SIB) in hadron mass splittings, but SIB effects in thermodynamic observables have only been studied in terms of the crossover temperature with unphysically heavy quarks. Motivated by the recent observation of an unexpectedly large ratio between the abundances of charged versus neutral kaons in heavy-ion collision experiments, we investigate the effects of SIB in QCD thermodynamics by computing observables for three non-degenerate flavors (Nf=1+1+1) with physical quark masses using dynamical improved staggered fermions. In particular, we investigate the difference between the u- and d-quark condensates and extract the pseudocritical temperature, the equation of state, and conserved-charge fluctuations, comparing results to standard Nf=2+1 simulations.
Related
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- Influence of configuration-interaction on isospin impurities and isospin symmetry breaking corrections to superallowed 0+→ 0+ beta decays
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- Isospin and flavor SU(3) symmetry breaking in doubly heavy baryons
BibTeX
@misc{clarke2026testing,
title = {{Testing strong isospin breaking effects in QCD thermodynamics}},
author = {D. A. Clarke and B. B. Brandt},
howpublished = {arXiv},
year = {2026},
month = sep,
doi = {10.48550/arxiv.2609.17725},
eprint = {2609.17725},
archivePrefix = {arXiv},
url = {https://arxiv.org/abs/2609.17725},
}
RIS
TY - UNPB
TI - Testing strong isospin breaking effects in QCD thermodynamics
AU - D. A. Clarke
AU - B. B. Brandt
PY - 2026
DA - 2026/09/15
PB - arXiv
DO - 10.48550/arxiv.2609.17725
UR - https://arxiv.org/abs/2609.17725
AB - Most modern lattice QCD calculations take the masses of the light quarks to be degenerate, setting m_u=m_d, a choice that, while not physical, increases computational efficiency and lowers the complexity of simulations and analysis. For many observables, the systematic error associated with this simplification is expected to be negligible, as Δm_ud=m_d−m_u is significantly below the QCD scale. So far lattice studies have examined the role of strong isospin breaking (SIB) in hadron mass splittings, but SIB effects in thermodynamic observables have only been studied in terms of the crossover temperature with unphysically heavy quarks. Motivated by the recent observation of an unexpectedly large ratio between the abundances of charged versus neutral kaons in heavy-ion collision experiments, we investigate the effects of SIB in QCD thermodynamics by computing observables for three non-degenerate flavors (N_f=1+1+1) with physical quark masses using dynamical improved staggered fermions. In particular, we investigate the difference between the u- and d-quark condensates and extract the pseudocritical temperature, the equation of state, and conserved-charge fluctuations, comparing results to standard N_f=2+1 simulations.
ER -