Search for: All records

Is the standard model charge-parity ( $CP$) violation ever enough to generate the observed baryon asymmetry? Yes! We introduce a mechanism of baryogenesis (and dark matter production) that can generate the entire observed baryon asymmetry of the Universe using the $CP$violation within standard model systems—a feat which no other mechanism currently proposed can achieve. Baryogenesis proceeds through a mesogenesis scenario but with well motivated additional dark sector dynamics: a field generates present day mass contributions for the particle mediating the decay responsible for baryogenesis. The effect is an enhancement of baryon production while evading present day collider constraints. The $CP$violation comes entirely from standard model contributions to neutral meson systems. Meanwhile, the dark dynamics generate gravitational waves that may be searched for with current and upcoming pulsar timing arrays, as we demonstrate with an example potential that is tuned to generate domain walls that annihilate later. This mechanism, , motivates probing a new parameter space as well as improving the sensitivity of existing mesogenesis searches at hadron and electron colliders. Published by the American Physical Society2025 

Leptophilic sub-MeV spin-zero dark matter (DM) decays into photons via one-loop processes, a scenario that has been in part overlooked in current literature. In this work, we provide updated and comprehensive upper limits on scalar, pseudoscalar, and axionlike DM-electron couplings based on the latest cosmic microwave background data from . Our bounds on the couplings are not only competitive with astrophysical and terrestrial experiments, but outperform them in certain regions of parameter space. Notably, we present the most stringent limits to date on scalar DM with masses around a few keV and pseudoscalar DM with masses between 100 eV and a few keV. Additionally, we explore, for the first time, the impact of implementing a cosmology-consistent treatment of energy deposition into the cosmic medium. Published by the American Physical Society2025 

We consider first order cosmological phase transitions (PTs) happening at late times below standard model temperatures $T_{\mathrm{PT}}\lesssim \mathrm{GeV}$. The inherently stochastic nature of bubble nucleation and the finite number of bubbles associated with a late-time PT lead to superhorizon fluctuations in the PT completion time. We compute how such fluctuations eventually source curvature fluctuations with universal properties, independent of the microphysics of the PT dynamics. Using cosmic microwave background (CMB) and large scale structure measurements, we constrain the energy released in a dark-sector PT. For $0.1\mathrm{eV}\lesssim T_{\mathrm{PT}}\lesssim \mathrm{keV}$this constraint is stronger than both the current bound from additional neutrino species $\mathrm{\Delta }{N}_{\mathrm{eff}}$, and in some cases, even CMB-S4 projections. Future measurements of CMB spectral distortions and pulsar timing arrays will also provide competitive sensitivity for $\mathrm{keV}\lesssim T_{\mathrm{PT}}\lesssim \mathrm{GeV}$. Published by the American Physical Society2024 

We introduce and study the first class of signals that can probe the dark matter in mesogenesis, which will be observable at current and upcoming large volume neutrino experiments. The well-motivated mesogenesis scenario for generating the observed matter-antimatter asymmetry necessarily has dark matter charged under the baryon number. Interactions of these particles with nuclei can induce nucleon decay with kinematics differing from spontaneous nucleon decay. We calculate the rate for this process and develop a simulation of the signal that includes important distortions due to nuclear effects. We estimate the sensitivity of DUNE, Super-Kamiokande, Hyper-Kamiokande, and JUNO to this striking signal. Published by the American Physical Society2024