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astro-ph.HE2025
New ultralight scalar particles and the mass-radius relation of white dwarfs -- the important role of Sirius B
Kai Bartnick, Detlev Koester, Rolf-Peter Kudritzki +3
We present the equation of state for two classes of new ultralight particles, a scalar field coupling to electrons and a light QCD axion field coupling to…
hep-ph2025
-Dwarfs: White Dwarfs probe Quadratically Coupled Scalars
Kai Bartnick, Konstantin Springmann, Stefan Stelzl +1
We study ultralight scalar fields with quadratic couplings to Standard-Model fermions and derive strong constraints from white-dwarf mass-radius data. Such couplings source scalar…