Publications (14)
-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…
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…
Heavy neutron stars from light scalars
Reuven Balkin, Javi Serra, Konstantin Springmann +2
We study how light scalar fields can change the stellar landscape by triggering a new phase of nuclear matter. Scalars coupled to nucleons can develop a non-trivial expectation val…
Momentum and Matter Matter for Axion Dark Matter Matters on Earth
Abhishek Banerjee, Itay M. Bloch, Quentin Bonnefoy +5
We investigate the implications of matter effects to searches for axion Dark Matter on Earth. The finite momentum of axion Dark Matter is crucial to elucidating the effects of Eart…
White dwarfs as a probe of exceptionally light QCD axions
Reuven Balkin, Javi Serra, Konstantin Springmann +2
We study the effects of exceptionally light QCD axions on the stellar configuration of white dwarfs. At finite baryon density, the non-derivative coupling of the axion to nucleons…
Natural Ultralight Dark Matter: The Quadratic Twin
Cédric Delaunay, Michael Geller, Zamir Heller-Algazi +2
Scalar ultralight dark matter (ULDM) is uniquely accessible to tabletop experiments such as clocks and interferometers, and its search has been the focus of a vast experimental eff…
The QCD Axion at Finite Density
Reuven Balkin, Javi Serra, Konstantin Springmann +1
We show how the properties of the QCD axion change in systems at finite baryonic density, such as neutron stars. At nuclear saturation densities, where corrections can be reliably…
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…
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…
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…
On the sensitivity of nuclear clocks to new physics
Andrea Caputo, Doron Gazit, Hans-Werner Hammer +4
The recent demonstration of laser excitation of the eV isomeric state of Thorium-229 is a significant step towards a nuclear clock. The low excitation energy likely res…
Runaway Relaxion from Finite Density
Reuven Balkin, Javi Serra, Konstantin Springmann +2
Finite density effects can destabilize the metastable vacua in relaxion models. Focusing on stars as nucleation seeds, we derive the conditions that lead to the formation and runaw…
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…
Density Induced Vacuum Instability
Reuven Balkin, Javi Serra, Konstantin Springmann +2
We consider matter density effects in theories with a false ground state. Large and dense systems, such as stars, can destabilize a metastable minimum and allow for the formation o…