Quark-gluon plasma acceleration hits 500 MeV at fireball edge

Scientists have mapped the acceleration inside quark-gluon plasma, an ultra-hot state of matter created in particle collisions, revealing that it reaches extreme levels at the fireball’s edge. The findings, reported on August 3, 2026, suggest acceleration could act as a new control parameter for matter governed by the strong force.

The research, led by Fudan University physicists Yu-Gang Ma and Xu-Guang Huang, combined the AMPT and UrQMD particle transport models with a Gaussian smearing method to transform particle distributions into continuous fluid fields. This allowed the team to track acceleration across collision energies from 3.5 GeV to 2.76 TeV.

According to the study, peak proper acceleration reaches several hundred MeV at both low and high energies, with the strongest transverse acceleration pointing outward near the fireball’s boundary. The edge becomes an acceleration hotspot because pressure drops rapidly while enthalpy density remains low, reinforcing the effect via the relativistic Euler equation.

At lower collision energies, nuclear stopping causes deceleration of up to about 500 MeV, while at ultrarelativistic energies, the nuclei pass through each other so quickly that they generate brief, intense acceleration pulses. Because the most powerful acceleration is concentrated along the boundary, the overall effect changes only slightly between head-on and angled collisions.

Professor Huang stated that acceleration is not merely a kinematic detail but may act as a thermodynamic control parameter of QCD matter. Through the Unruh effect, an acceleration of several hundred MeV could resemble temperatures near the QCD transition temperature, potentially adding an “acceleration axis” to the phase structure of QCD matter and influencing the chiral and confinement transitions.

The researchers plan to incorporate more realistic hydrodynamic evolution into their calculations and seek experimental signals, such as patterns in hyperon spin polarization, that could reveal acceleration’s influence. The work, published in Nuclear Science and Techniques, aims to turn non-inertial quantum effects into measurable signatures at colliders like RHIC and the LHC.