EPJ Plus Highlight - Understanding explosive transitions in propagating flames

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Published on 19 May 2025

Mathematical analysis sheds new light on the mechanisms which unfold as propagating flames transition from one type of combustion to another

As a flame propagates through a mixture of air and flammable fuel, it can suddenly transition from one type of combustion to another. While it initially spreads at subsonic speeds through a process named ‘deflagration’, the flame will suddenly switch to a supersonic motion, driving a shockwave which compresses and ignites the fuel directly in front of it: a process named ‘detonation’. To date, however, some details of the mechanisms which unfold as this transition takes place are still being investigated.

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EPJ A Topical Collection: Radiative corrections: from medium to high energy experiments

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Published on 16 May 2025

Guest Editors: Andrei Afanasev, Jan C. Bernauer, Ethan W. Cline, Ronald Gilman, André Peshier, Hubert Spiesberger

Modern lepton-scattering experiments at medium to high energy achieve a precision that requires an accurate understanding of radiative corrections, including the re- sulting uncertainties of relevant observables in the given experimental setting. The development of associated tools is a subject of active research. It is a showcase for a fruitful interplay between theoretical and experimental efforts, and of particular importance with regard to the ongoing experimental program at Jefferson Lab and to the future Electron-Ion Collider at the Brookhaven National Lab.

This Topical Collection focuses on spin-polarized and unpolarized fixed target ex- periments with electrons, e⁺e⁻ collisions, meson decays, and elastic e^±p and μ^±p scattering, from both experimental and theoretical perspectives.

The articles included in the Topical Collection are available here and are freely accessible until 16 July 2025. For further information read the Editorial.

EPJ A Topical Collection: Heavy and Super-Heavy Nuclei and Elements: Production and Properties

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Published on 12 May 2025

Guest Editors: Nicolas Alamanos, Maria José Garcia Borge, Sigurd Hofmann, Peter Möller, Andrey G. Popeko

Interest in the possible existence of elements (SuperHeavy Elements, SHE) at the next doubly-magic numbers beyond ²⁰⁸₈₂Pb₁₂₆, sufficiently stable to allow experimental studies of their properties, has been around since at least the 1950ies. In analogy with the magic neutron number 126 it was assumed that the next magic proton number would be Z = 126. However in the mid sixties it was realized that already available, calculated single-particle diagrams showed that Z = 114 would be a more plausible next magic proton number. This realization, the advent of the Strutinsky method, and improving experimental facilities led to many theoretical studies of SHE properties and to experimental efforts to form those. However in the next 15 years or so only a very few new elements (up to Z = 106) were discovered, none near the postulated island of stability. In a Nature article in 1979 Hermann reviewed the status and presented a somewhat bleak view of future prospects. Others had even remarked that the earlier Nobel symposium 27 in 1974 seemed to be the funeral services for SHE.

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