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Updated: Jan 6, 2026

Development of an Experimental Setup for the Measurement of the Coefficient of Restitution under Vacuum Conditions
Published on: March 29, 2016
How to Observe the Vacuum Decay in Low-Energy Heavy-Ion Collisions
I A Maltsev1, V M Shabaev1, R V Popov1
1Department of Physics, St. Petersburg State University, Universitetskaya naberezhnaya 7/9, 199034 St. Petersburg, Russia.
Abstract:
In slow collisions of two bare nuclei with the total charge larger than the critical value Z_{cr}≈173, the initially neutral vacuum can spontaneously decay into the charged vacuum and two positrons. The detection of the spontaneous emission of positrons would be direct evidence of this fundamental phenomenon. However, the spontaneously produced particles are indistinguishable from the dynamical background in the positron spectra. We show that the vacuum decay can nevertheless be observed via impact-sensitive measurements of pair-production probabilities. The possibility of such an observation is demonstrated using numerical calculations of pair production in low-energy collisions of heavy nuclei.
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