Baryon Electric Charge Correlation as a Magnetometer of QCD

Area of Science:

• Nuclear Physics
• Quantum Chromodynamics (QCD)

Background:

• The correlation between net baryon number and electric charge (χ_{11}^{BQ}) is a key observable in QCD.
• Understanding QCD under extreme conditions, such as those present in heavy ion collisions, is crucial.

Purpose of the Study:

• To investigate the behavior of χ_{11}^{BQ} and the ratio of chemical potentials (μ_{Q}/μ_{B}) in the presence of magnetic fields.
• To establish χ_{11}^{BQ} and μ_{Q}/μ_{B} as potential magnetometers for QCD and probes for magnetic field detection in relativistic heavy ion collisions.

Main Methods:

• Lattice QCD computations were performed using highly improved staggered quarks with physical pion mass (M_{π}=135 MeV).
• Simulations were conducted on N_{τ}=8 and N_{τ}=12 lattices to analyze the magnetic field dependence of χ_{11}^{BQ} and μ_{Q}/μ_{B}.

Main Results:

• χ_{11}^{BQ} increases rapidly with magnetic field strength (eB) starting from eB≳2M_{π}^{2}, doubling by eB≃8M_{π}^{2}.
• The ratio μ_{Q}/μ_{B} exhibits significant dependence on magnetic field strength, deviating from the charge-to-baryon number ratio in colliding nuclei.

Conclusions:

• The study demonstrates that χ_{11}^{BQ} and μ_{Q}/μ_{B} are sensitive to magnetic fields, serving as valuable probes.
• These findings provide essential baselines for effective theory and model studies, and support the use of these observables in detecting magnetic fields in heavy ion collisions.