activity
20242026
collaborators

6 papers

hep-ph2026

-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…

hep-ph2026

The COSMIC WISPers White Paper: The physics case for Weakly Interacting Slim Particles

Ariel Arza, Deniz Aybas, Shyam Balaji +124

Axions and other very weakly interacting slim particles (WISPs), with masses below 1 GeV, arise naturally in many extensions of the Standard Model of particle physics. In particula…

astro-ph.HE2026

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

A Universal Bound on QCD Axions from Supernovae

Konstantin Springmann, Michael Stadlbauer, Stefan Stelzl +1

We identify a new production channel for QCD axions in supernova environments that contributes to axion emissivity for all models solving the strong CP problem. This channel arises…

hep-ph2025

From Supernovae to Neutron Stars: A Systematic Approach to Axion Production at Finite Density

Konstantin Springmann, Michael Stadlbauer, Stefan Stelzl +1

We present a systematic study of QCD axion production in environments with finite baryon density and temperature, implying significant changes to axion phenomenology. Within heavy…

hep-ph2024

Constraining Light QCD Axions with Isolated Neutron Star Cooling

Antonio Gómez-Bañón, Kai Bartnick, Konstantin Springmann +1

The existence of light QCD axions, whose mass depends on an additional free parameter, can lead to a new ground state of matter, where the sourced axion field reduces the nucleon e…