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Creators/Authors contains: "McGehee, Robert"

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  1. ; ; ; (, Physical Review D)
    WIMP-type dark matter may have additional interactions that break baryon number, leading to induced nucleon decays which are subject to direct experimental constraints from proton decay experiments. In this work, we analyze the possibility of continuous baryon destruction, deriving strong limits from the dark matter accumulating inside old neutron stars, as such a process leads to excess heat generation. We construct the simplest particle dark matter model that breaks the baryon and lepton numbers separately but conserves B − L . Virtual exchange by DM particles in this model results in dinucleon decay via n n → n ν ¯ and n p → n e + processes. Published by the American Physical Society2025 
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    Free, publicly-accessible full text available January 1, 2026
  2. ; ; ; ; (, Physical Review Letters)
    We consider first order cosmological phase transitions (PTs) happening at late times below standard model temperatures T PT ≲ 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     eV ≲ T PT ≲ keV this constraint is stronger than both the current bound from additional neutrino species Δ N 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 keV ≲ T PT ≲ GeV . Published by the American Physical Society2024 
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    Free, publicly-accessible full text available November 1, 2025
  3. ; ; ; (, Physical Review D)
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  4. ; ; ; (, Physical Review D)
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  5. ; ; ; (, Journal of High Energy Physics)
    A bstract We present a model of self-interacting dark matter based on QCD-like theories and inspired by the proximity of a 0 (980 ± 20) to the $$ K\overline{K} $$ K K ¯ (990) threshold. Dark matter is comprised of dark pions which self-scatter via the σ resonance close to the ππ threshold. While the linear sigma model serves as a qualitative guide, a fully unitary description of the scattering in the strongly coupled regime is given by effective range theory. The introduction of a kinetically mixed dark photon allows the dark pion to either freeze-out or -in. We study the viable parameter space which explains the observed relic abundance while evading all current constraints. Searches for dark matter self interactions at different scales, (in)direct detection signals, and (in)visibly-decaying dark photons will test this model in the near future. 
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  6. ; ; (, Physical Review Letters)
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  7. ; ; ; (, Physical Review D)
    null (Ed.)
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  8. ; ; ; (, Journal of High Energy Physics)
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  9. ; ; ; ; (, Journal of High Energy Physics)
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  10. ; ; (, Physical Review D)
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