Published in Journal of Cosmology and Astroparticle Physics
Low energy imprints of modifications to general relativity are often found in pressure balance equations inside stars. These modifications are then amenable to tests via astrophysical phenomena, using observational effects in stellar astrophysics that crucially depend on such equations. One such effect is tidal disruption of stars in the vicinity o...
Published in Journal of Cosmology and Astroparticle Physics
We revisit stellar energy-loss bounds on the Yukawa couplings g B,L of baryophilic and leptophilic scalars ϕ. The white-dwarf luminosity function yields g B ≲ 7 × 10-13 and g L ≲ 4 × 10-16, based on bremsstrahlung from 12C and 16O collisions with electrons. In models with a Higgs portal, this also implies a bound on the scalar-Higgs mixing angle si...
Published in Journal of Cosmology and Astroparticle Physics
We explore the internal structures of the white dwarfs in two different modified theories of gravity: (i) scalar-tensor-vector gravity and (ii) beyond Horndeski theories of G 3 type. The modification of the gravitational force inside the white dwarf results in the modification of the mass and radius of the white dwarf. We use observational data fro...
Published in Journal of Cosmology and Astroparticle Physics
The dark matter content of globular clusters, highly compact gravity-bound stellar systems, is unknown. It is also generally unknowable, due to their mass-to-light ratios typically ranging between 1-3 in solar units, accommodating a dynamical mass of dark matter at best comparable to the stellar mass. That said, recent claims in the literature assu...
Published in Journal of Cosmology and Astroparticle Physics
First order phase transitions in the early universe could produce a gravitational-wave background that might be detectable by the Laser Interferometer Space Antenna (LISA). Such an observation would provide evidence for physics beyond the Standard Model. We study the ability of LISA to observe a gravitational-wave background from phase transitions ...
Published in Journal of Cosmology and Astroparticle Physics
We derive improved stellar luminosity limits on a generic light CP-even scalar field S mixing with the Standard Model (SM) Higgs boson from the supernova SN1987A, the Sun, red giants (RGs) and white dwarfs (WDs). For the first time, we include the geometric effects for the decay and absorption of S particles in the stellar interior. For SN1987A and...
Published in Journal of Cosmology and Astroparticle Physics
In this paper, we study how a Yukawa coupling of the Standard Model fermions to a light scalar field affects the stellar structure of cold stellar remnants such as neutron stars. We elucidate the stellar structure phenomenology using a simple model of a massive scalar coupled to a single dominant fermion with no other interactions. For a broad scal...
