Baryon Electric Charge Correlation as a Magnetometer of QCD

Abstract

The correlation between net baryon number and electric charge, χ11BQ, can serve as a magnetometer of QCD. This is demonstrated by lattice QCD computations using the highly improved staggered quarks with physical pion mass of Mπ=135 MeV on Nτ=8 and 12 lattices. We find that χ11BQ along the transition line starts to increase rapidly with magnetic field strength eB≳2Mπ2 and by a factor 2 at eB≃8Mπ2. Furthermore, the ratio of electric charge chemical potential to baryon chemical potential, μQ/μB, shows significant dependence on the magnetic field strength and varies from the ratio of electric charge to baryon number in the colliding nuclei in heavy ion collisions. These results can provide baselines for effective theory and model studies, and both χ11BQ and μQ/μB could be useful probes for the detection of magnetic fields in relativistic heavy ion collision experiments as compared with corresponding results from the hadron resonance gas model. Published by the American Physical Society 2024