365 citations · 2k across the 48 of their papers we have counts for
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Heavy Higgsino Dark Matter at the Scale of the Vanishing Higgs Quartic
James Unwin
The Standard Model Higgs quartic coupling runs to zero around GeV at , suggestive of an ultraviolet boundary condition at this scale. In a well-motiva…
Axion Portal Dark Matter and the LUX-ZEPLIN High-Recoil Event
James Unwin
LUX-ZEPLIN (LZ) has reported one event compatible with a nuclear recoil. While initial attention has focused on inelastic dark matter, that interpretation depend…
Constraining the Coexistence of Primordial Black Holes and Particle Dark Matter with Neutrino Observations
Prolay Chanda, Sagnik Mukherjee, James Unwin
Primordial black holes (PBH) with a uniform mass scale could contribute up to 1\% of the gravitationally inferred dark matter relic abundance and remain consistent with observation…
Next-to-Minimal Freeze-in Dark Matter
Nicolás Bernal, Sagnik Mukherjee, James Unwin
If the dark matter mass exceeds the highest temperature of the thermal bath, then dark matter production is Boltzmann suppressed. This opens new possibilities for dark matter model…
Minimal Freeze-in Dark Matter: Reviving electroweak doublet dark matter with Boltzmann suppressed freeze-in
Nicolás Bernal, Sagnik Mukherjee, James Unwin
Dark matter communicating with the Standard Model solely via electroweak interactions provides a compelling picture. However, thermal freeze-out of electroweak doublet dark matter…
Boltzmann Suppressed Ultraviolet Freeze-in
Nicolás Bernal, Sagnik Mukherjee, James Unwin
If the dark matter mass exceeds the maximum temperature of the Universe (), then its production rate will be Boltzmann suppressed. The important implications o…
Parametric Coincidence in the Baryon to Dark Matter Ratio from Affleck-Dine Baryogenesis and UV Freeze-in Dark Matter
Jae Hyeok Chang, Chang Sub Shin, James Unwin
We highlight that the observed concurrence between the baryon and dark matter relic densities can be explained via a parametric coincidence between two distinct production mechanis…
Constraining the Coexistence of Freeze-in Dark Matter and Primordial Black Holes
Prolay Chanda, Sagnik Mukherjee, James Unwin
Particle dark matter and primordial black holes (PBH) might coexist with appreciable cosmic abundances, with both contributing to the observed dark matter density . Lar…
Towards TeV-Scale Supersymmetric Electroweak Baryogenesis
Oleksii Matsedonskyi, James Unwin, Qingyun Wang
Electroweak baryogenesis (EWBG) offers a compelling narrative for the generation of the baryon asymmetry, however it cannot be realised in the Standard Model, and leads to severe e…
Improved Constraints on Dark Matter Annihilations Around Primordial Black Holes
Prolay Chanda, Jakub Scholtz, James Unwin
Cosmology may give rise to appreciable populations of both particle dark matter and primordial black holes (PBH) with the combined mass density providing the observationally inferr…
Electroweak Symmetry Non-Restoration from Dark Matter
Oleksii Matsedonskyi, James Unwin, Qingyun Wang
Restoration of the electroweak symmetry at temperatures around the Higgs mass is linked to tight phenomenological constraints on many baryogenesis scenarios. A potential remedy can…
Decoupling of Asymmetric Dark Matter During an Early Matter Dominated Era
Prolay Chanda, James Unwin
In models of Asymmetric Dark Matter (ADM) the relic density is set by a particle asymmetry in an analogous manner to the baryons. Here we explore the scenario in which ADM decouple…
Reviving and Higgs Mediated Dark Matter Models in Matter Dominated Freeze-out
Prolay Chanda, Saleh Hamdan, James Unwin
It is quite conceivable that dark matter freeze-out occurred during an early period of matter domination, in which case the evolution and relic abundance differ from standard freez…
What if Planet 9 is a Primordial Black Hole?
Jakub Scholtz, James Unwin
We highlight that the anomalous orbits of Trans-Neptunian Objects (TNOs) and an excess in microlensing events in the 5-year OGLE dataset can be simultaneously explained by a new po…
Ultraviolet Freeze-in and Non-Standard Cosmologies
Nicolás Bernal, Fatemeh Elahi, Carlos Maldonado +1
A notable feature of UV freeze-in is that the relic density is strongly dependent on the highest temperatures of the thermal bath, and a common assumption is that the relevant 'hig…
Establishing the Dark Matter Relic Density in an Era of Particle Decays
Carlos Maldonado, James Unwin
If the early universe is dominated by an energy density which evolves other than radiation-like the normal Hubble-temperature relation is broken and dark matter reli…
Protecting the Axion with Local Baryon Number
Michael Duerr, Kai Schmidt-Hoberg, James Unwin
The Peccei-Quinn (PQ) solution to the Strong CP Problem is expected to fail unless the global symmetry U(1) is protected from Planck-scale operators up to high mass di…
Dark Matter Freeze-out During Matter Domination
Saleh Hamdan, James Unwin
We highlight the general scenario of dark matter freeze-out whilst the energy density of the universe is dominated by a decoupled non-relativistic species. Decoupling during matter…
Symmetric and Asymmetric Reheating
Edward Hardy, James Unwin
We study models in which the inflaton is coupled to two otherwise decoupled sectors, and the effect of preheating and related processes on their energy densities during the evoluti…
Superheavy Thermal Dark Matter and Primordial Asymmetries
Joseph Bramante, James Unwin
The early universe could feature multiple reheating events, leading to jumps in the visible sector entropy density that dilute both particle asymmetries and the number density of f…
Axial Vector and Anomaly Cancellation
Ahmed Ismail, Wai-Yee Keung, Kuo-Hsing Tsao +1
Whilst the prospect of new gauge bosons with only axial couplings to the Standard Model (SM) fermions is widely discussed, examples of anomaly-free renormalisable models are l…
Flooded Dark Matter and S Level Rise
Lisa Randall, Jakub Scholtz, James Unwin
Most dark matter (DM) models set the DM relic density by some interaction with Standard Model particles. Such models generally assume the existence of Standard Model particles earl…
UltraViolet Freeze-in
Fatemeh Elahi, Christopher Kolda, James Unwin
If dark matter is thermally decoupled from the visible sector, the observed relic density can potentially be obtained via freeze-in production of dark matter. Typically in such mod…
Towards Cogenesis via Asymmetric Freeze-in: The Who Came-in from the Cold
James Unwin
In models of freeze-in the dark matter (DM) is decoupled from the visible sector and initially has a depleted number density. The hidden and visible sectors are connected only via…