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1. Resonant conversion of axion dark radiation into terahertz electromagnetic radiation in a neutron star magnetosphere

   https://doi.org/10.1103/PhysRevD.110.103020  

   Long, Andrew J; Schiappacasse, Enrico D (November 2024, Physical Review D)

   In the strong magnetic field of a neutron star’s magnetosphere, axions coupled to electromagnetism develop a nonzero probability to convert into photons. Past studies have revealed that the axion-photon conversion can be resonantly enhanced. We recognize that the axion-photon resonance admits two parametrically distinct resonant solutions, which we call the mass-matched resonance and the Euler-Heisenberg assisted resonance. The mass-matched resonance occurs at a point in the magnetosphere where the radially-varying plasma frequency crosses the axion mass ${\omega }_{\mathrm{pl}}\approx m_a$. The Euler-Heisenberg assisted resonance occurs where the axion energy satisfies $\omega \approx (2{\omega }_{\mathrm{pl}}^2/7g_{\gamma \gamma \gamma \gamma }{\overline{B}}^2{)}^{1/2}$. This second resonance is made possible though the strong background magnetic field $\overline{B}$, as well as the nonzero Euler-Heisenberg four-photon self-interaction, which has the coupling $g_{\gamma \gamma \gamma \gamma }=8{\alpha }^2/45m_e^4$. We study the resonant conversion of relativistic axion dark radiation into photons via the Euler-Heisenberg assisted resonance, and we calculate the expected electromagnetic radiation assuming different values for the axion-photon coupling $g_{a\gamma \gamma }$and different amplitudes for the axion flux onto the neutron star ${\mathrm{\Phi }}_a$. We briefly discuss several possible sources of axion dark radiation. Achieving a sufficiently strong axion flux to induce a detectable electromagnetic signal seems unlikely. Published by the American Physical Society2024 

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2. Electromagnetic modeling and science reach of $\text{DMRadio-}{\mathrm{m}}^3$

   https://doi.org/10.1103/bwgd-kxsb  

   AlShirawi, A; Ankel, V; Bartram, C; Begin, J; Bell, C; Benabou, J N; Brouwer, L; Chaudhuri, S; Cho, H-M; Corbin, J; et al (September 2025, Physical review D)

   $\text{DMRadio-}{\mathrm{m}}^3$is an experimental search for dark matter axions. It uses a solenoidal dc magnetic field to convert an axion dark-matter signal to an ac electromagnetic response in a coaxial copper pickup. The current induced by this axion signal is measured by dc SQUIDs. $\text{DMRadio-}{\mathrm{m}}^3$is designed to be sensitive to Kim-Shifman-Vainshtein-Zakharov (KSVZ) and Dine-Fischler-Srednicki-Zhitnisky (DFSZ) QCD axion models in the 10–200 MHz ( $41\mathrm{neV}/c^2–0.83\mathrm{\mu }\mathrm{eV}/c^2$) range, and to axions with $g_{a\gamma \gamma }=g_{a\gamma \gamma ,\mathrm{DFSZ}}\left(30\mathrm{MHz}\right)=1.87\times {10}^{-17}{\mathrm{GeV}}^{-1}$over 5–30 MHz as an extended goal. In this work, we present the electromagnetic modeling of the response of the experiment to an axion signal over the full frequency range of $\text{DMRadio-}{\mathrm{m}}^3$, which extends from the low-frequency, lumped-element limit to a regime where the axion Compton wavelength is only a factor of 2 larger than the detector size. With these results, we determine the live time and sensitivity of the experiment. The primary science goal of sensitivity to DFSZ axions across 30–200 MHz can be achieved with a $3\sigma$live scan time of 2.9 years. 

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3. Measurements of the Branching Fraction, Polarization, and $CP$ Asymmetry for the Decay $B^0\to \omega \omega$

   https://doi.org/10.1103/PhysRevLett.133.081801  

   Guan, Y; Schwartz, A J; Kinoshita, K; Adachi, I; Aihara, H; Al_Said, S; Asner, D M; Atmacan, H; Ayad, R; Bahinipati, S; et al (August 2024, Physical Review Letters)

   We present a comprehensive study of $B^0\to \omega \omega$decays using $772\times {10}^{6}B\overline{B}$pairs collected with the Belle detector at the KEKB $e^{+}{e}^{-}$collider. This process is a suppressed charmless decay into two vector mesons and can exhibit interesting polarization and $CP$violation. The decay is observed for the first time with a significance of 7.9 standard deviations. We measure a branching fraction $\mathcal{B}=(1.53\pm 0.29\pm 0.17)\times {10}^{-6}$, a fraction of longitudinal polarization $f_L=0.87\pm 0.13\pm 0.13$, and a time-integrated $CP$asymmetry $A_{CP}=-0.44\pm 0.43\pm 0.11$, where the first uncertainties listed are statistical and the second are systematic. This is the first observation of $B^0\to \omega \omega$and the first measurements of $f_L$and $A_{CP}$for this decay. Published by the American Physical Society2024 

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4. $\omega$ Meson from Lattice QCD

   https://doi.org/10.1103/PhysRevLett.133.211906  

   Yan, Haobo; Mai, Maxim; Garofalo, Marco; Meißner, Ulf-G; Liu, Chuan; Liu, Liuming; Urbach, Carsten (November 2024, Physical Review Letters)

   Many excited states in the hadron spectrum have large branching ratios to three-hadron final states. Understanding such particles from first principles QCD requires input from lattice QCD with one-, two-, and three-meson interpolators as well as a reliable three-body formalism relating finite-volume spectra at unphysical pion mass values to the scattering amplitudes at the physical point. In this work, we provide the first-ever calculation of the resonance parameters of the $\omega$meson from lattice QCD, including an update of the formalism through matching to effective field theories. The main result of this pioneering study, the pole position of the $\omega$meson at $\sqrt{s_{\omega }}=\left(778.0\right(11.2)-i3.0(5\left)\right)\mathrm{MeV}$, agrees reasonably well with experiment. In addition we provide an estimate of the $\omega -\rho$mass difference as 29(15) MeV. Published by the American Physical Society2024 

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5. First Search for Ultralight Dark Matter Using a Magnetically Levitated Particle

   https://doi.org/10.1103/PhysRevLett.134.251001  

   Amaral, Dorian_W P; Uitenbroek, Dennis G; Oosterkamp, Tjerk H; Tunnell, Christopher D (June 2025, Physical Review Letters)

   We perform the first search for ultralight dark matter using a magnetically levitated particle. A submillimeter permanent magnet is levitated in a superconducting trap with a measured force sensitivity of $0.2\mathrm{fN}/\sqrt{\mathrm{Hz}}$. We find no evidence of a signal and derive limits on dark matter coupled to the difference between baryon and lepton number, $B-L$, in the mass range $(1.10360-1.10485)\times {10}^{-13}\mathrm{eV}/c^2$. Our most stringent limit on the coupling strength is $g_{B-L}\lesssim 2.98\times {10}^{-21}$. We propose the POLONAISE (Probing Oscillations using Levitated Objects for Novel Accelerometry In Searches of Exotic physics) experiment, which features short-, medium-, and long-term upgrades that will give us leading sensitivity in a wide mass range, demonstrating the promise of this novel quantum sensing technology in the hunt for dark matter. Published by the American Physical Society2025 

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