The nature of the narrow peaks in the $e^+e^-$ pair production in heavy ion collisions

TL;DR

The paper investigates narrow peaks in $e^+e^-$ pair production during heavy ion collisions, attributing them to pair coupling with intense magnetic fields generated by fast nuclei, revealing magnetic trapping effects.

Contribution

It proposes a novel explanation for narrow peaks in $e^+e^-$ spectra based on magnetic trapping of pairs in strong magnetic fields during heavy ion collisions.

Findings

Identification of narrow peaks in $e^+e^-$ energy distribution.

Attribution of peaks to pair coupling with magnetic fields.

Estimation of magnetic trap parameters and effects.

Abstract

Experiments on heavy ion collisions performed at GSI (Darmstadt, Germany) revealed series of narrow quasi-equidistant peaks in the energy distribution of the produced $e^+e^-$ pairs in the range from 1.5 to 2.0 MeV which are ascribed to the pair coupling with a strong magnetic field generated by fast nuclei with $Z\sim90$. The pair is captured in the magnetic trap with dimensions of $10^{-10}$ cm and average field $\sim 5 \cdot 10^{12}$ Gs and, in turn, confines this magnetic field in the trap during $\sim 10^{-19}$ s due to the Alfven effect of magnetic field "freezing-in" into the conducting medium.