Abstract: 

 

We presents first measurements of $e^+e^-$ pair production from light-light scattering 

in non-central high-energy heavy ion collisions. 

The yields peak distinctly at low transverse momentum between 40 to 60 MeV/c and 

show smooth mass distribution absent from any vector-meson contamination. 

The production can be explained quantitatively with exclusive Breit-Wheeler process. 

The measured pT distributions are significantly broader than model calculation for baseline 

UPC collisions and are different between Au+Au and U+U collisions. 

Our experimental measurements with quantitative model calculations provide a possible tool to systematically 

study strong magnetic field at peta-Tesla scale with controllable impact-parameter sensitive observables.