212 citations · 1.6k across the 40 of their papers we have counts for
34 papers · 1 filter
Cosmic Birefringence and Axiogenesis
Raymond T. Co, Lawrence J. Hall, Keisuke Harigaya +1
Recent analyses of Planck and ACT CMB data report a hint of isotropic cosmic birefringence (), corresponding to a parity-violating rotation of pol…
Dark Matter and Baryon Asymmetry from Monopole-Axion Interactions
Raymond T. Co, Keisuke Harigaya, Isaac R. Wang +1
We introduce a novel mechanism where the kinetic energy of a rotating axion can be dissipated by the interactions with dark magnetic monopoles. This mechanism leads to a framework…
Enhanced Matter Power Spectrum from Axion Kination after Big Bang Nucleosynthesis
Raymond T. Co, Nicolas Fernandez, Akshay Ghalsasi +2
Despite stringent constraints from Big Bang Nucleosynthesis (BBN) and cosmic microwave background (CMB) observations, it is still possible for well-motivated particle physics model…
Acoustic Misalignment Mechanism for Axion Dark Matter
Arushi Bodas, Raymond T. Co, Akshay Ghalsasi +2
A rotation in the field space of a complex scalar field corresponds to a Bose-Einstein condensation of charges. We point out that fluctuations in this rotating condensate ex…
Axion baryogenesis puts a new spin on the Hubble tension
Raymond T. Co, Nicolas Fernandez, Akshay Ghalsasi +2
We show that a rotating axion field that makes a transition from a matter-like equation of state to a kination-like equation of state around the epoch of recombination can signific…
Lepto-axiogenesis with light right-handed neutrinos
Patrick Barnes, Raymond T. Co, Keisuke Harigaya +1
We study lepto-axiogenesis in theories where the right-handed neutrino is light enough that its dynamics affect the determination of the baryon asymmetry. When compared with theori…
Axion cogenesis without isocurvature perturbations
Raymond T. Co, Masaki Yamada
Axion rotations can simultaneously explain the dark matter abundance and the baryon asymmetry of the Universe by kinetic misalignment and axiogenesis. We consider a scenario in whi…
Gravity as a Portal to Reheating, Leptogenesis and Dark Matter
Basabendu Barman, Simon Cléry, Raymond T. Co +2
We show that a minimal scenario, utilizing only the graviton as an intermediate messenger between the inflaton, the dark sector and the Standard Model (SM), is able to generate $si…
Baryogenesis from Decaying Magnetic Helicity in Axiogenesis
Raymond T. Co, Valerie Domcke, Keisuke Harigaya
Generating axion dark matter through the kinetic misalignment mechanism implies the generation of large asymmetries for Standard Model fermions in the early universe. Even if these…
Enhancing Searches for Heavy QCD Axions via Dimuon Final States
Raymond T. Co, Soubhik Kumar, Zhen Liu
Heavy QCD axions are well-motivated extensions of the QCD axion that address the quality problem while still solving the strong CP problem. Owing to the gluon coupling, critical fo…
Lepto-axiogenesis and the scale of supersymmetry
Patrick Barnes, Raymond T. Co, Keisuke Harigaya +1
If the Peccei-Quinn field containing the QCD axion undergoes rotations in the early universe, the dimension-five operator responsible for neutrino masses can generate a lepton asym…
Discovery potential for split supersymmetry with thermal dark matter
Raymond T. Co, Aaron Pierce, Benjamin Sheff +1
Supersymmetric extensions of the Standard Model with scalar superpartners above 10 TeV are well motivated since the Higgs boson mass can be explained by quantum corrections while m…
Axiogenesis with a Heavy QCD Axion
Raymond T. Co, Tony Gherghetta, Keisuke Harigaya
We demonstrate that the observed cosmological excess of matter over antimatter may originate from a heavy QCD axion that solves the strong CP problem but has a mass much larger tha…
Inflationary Gravitational Leptogenesis
Raymond T. Co, Yann Mambrini, Keith A. Olive
We consider the generation of the baryon asymmetry in models with right-handed neutrinos produced through gravitational scattering of the inflaton during reheating. The right-hande…
New Ideas in Baryogenesis: A Snowmass White Paper
Gilly Elor, Julia Harz, Seyda Ipek +21
The Standard Model of Particle Physics cannot explain the observed baryon asymmetry of the Universe. This observation is a clear sign of new physics beyond the Standard Model. Ther…
Early-Universe Model Building
Pouya Asadi, Saurabh Bansal, Asher Berlin +37
Theoretical investigations into the evolution of the early universe are an essential part of particle physics that allow us to identify viable extensions to the Standard Model as w…
Cosmic Perturbations from a Rotating Field
Raymond T. Co, Keisuke Harigaya, Aaron Pierce
Complex scalar fields charged under approximate symmetries appear in well-motivated extensions of the Standard Model. One example is the field that contains the QCD axion fi…
R-Parity Violation Axiogenesis
Raymond T. Co, Keisuke Harigaya, Zachary Johnson +1
We show that the rotation of the QCD axion field, aided by violation from supersymmetric -parity violating couplings, can yield the observed baryon abundance. Strong sphal…
Gravitational Wave and CMB Probes of Axion Kination
Raymond T. Co, David Dunsky, Nicolas Fernandez +4
Rotations of an axion field in field space provide a natural origin for an era of kination domination, where the energy density is dominated by the kinetic term of the axion field,…
The Race to Find Split Higgsino Dark Matter
Raymond T. Co, Benjamin Sheff, James D. Wells
Split higgsinos are a compelling class of models to explain dark matter and may be on the verge of detection by multiple current experimental avenues. The idea is based on a large…
Gravitational Waves and Dark Photon Dark Matter from Axion Rotations
Raymond T. Co, Keisuke Harigaya, Aaron Pierce
An axion rotating in field space can produce dark photons in the early universe via tachyonic instability. This explosive particle production creates a background of stochastic gra…
Predictions for Axion Couplings from ALP Cogenesis
Raymond T. Co, Lawrence J. Hall, Keisuke Harigaya
Adding an axion-like particle (ALP) to the Standard Model, with a field velocity in the early universe, simultaneously explains the observed baryon and dark matter densities. This…
Lepto-Axiogenesis
Raymond T. Co, Nicolas Fernandez, Akshay Ghalsasi +2
We propose a baryogenenesis mechanism that uses a rotating condensate of a Peccei-Quinn (PQ) symmetry breaking field and the dimension-five operator that gives Majorana neutrino ma…
Axion Emission Can Explain a New Hard -ray Excess from Nearby Isolated Neutron Stars
Malte Buschmann, Raymond T. Co, Christopher Dessert +1
Axions may be produced thermally inside the cores of neutron stars (NSs), escape the stars due to their feeble interactions with matter, and subsequently convert into X-rays in the…