collaborators

7 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

Constraints on light QCD and CP-violating axions from the death line of rotation-powered pulsars

Samuel J. Witte, Andrea Caputo, Stefan Stelzl +3

For axions that couple to nucleons, the presence of dense nuclear matter can displace the axion from its vacuum minimum, sourcing large field gradients around neutron stars (and, m…

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

The Bearable Inhomogeneity of the Baryon Asymmetry

Hengameh Bagherian, Majid Ekhterachian, Stefan Stelzl

We study the implications of precision measurements of light-element abundances, in combination with the Cosmic Microwave Background, for scenarios of physics beyond the Standard M…