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1. First Observation of Cyclotron Radiation from MeV-Scale $e^{\pm }$ following Nuclear $\beta$ Decay

   https://doi.org/10.1103/PhysRevLett.131.082502  

   Byron, W; Harrington, H; Taylor, R J; DeGraw, W; Buzinsky, N; Dodson, B; Fertl, M; García, A; Garvey, G; Graner, B; et al (August 2023, Physical Review Letters)

   We present an apparatus for detection of cyclotron radiation yielding a frequency-based β  kinetic energy determination in the 5 keV to 2.1 MeV range, characteristic of nuclear β decays. The cyclotron frequency of the radiating β particles in a magnetic field is used to determine the β energy precisely. Our work establishes the foundation to apply the cyclotron radiation emission spectroscopy (CRES) technique, developed by the Project 8 Collaboration, far beyond the 18-keV tritium endpoint region. We report initial measurements of β−’s from 6He and βþ’s from 19Ne decays to demonstrate the broadband response of our detection system and assess potential systematic uncertainties for β spectroscopy over the full (MeV) energy range. To our knowledge, this is the first direct observation of cyclotron radiation from individual highly relativistic β’s in a waveguide. This work establishes the application of CRES to a variety of nuclei, opening its reach to searches for new physics beyond the TeV scale via precision β-decay measurements. 

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2. Radiative energy and mass shifts of quantum cyclotron states

   https://doi.org/10.1140/epjd/s10053-025-00982-3  

   Jentschura, U_D (April 2025, The European Physical Journal D)

   AbstractWe discuss relativistic and radiative corrections to the energies of quantum cyclotron states. In particular, it is shown analytically that the leading logarithmic radiative (self-energy) correction to the bound-state energy levels of quantum cyclotron states is state independent and must be interpreted as a magnetic field-dependent correction to the electron’s mass in a Penning trap. Graphical abstract 

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3. Measurement of the hyperfine coupling constants and absolute energies of the $12s {}^2{S}_{1/2}, 13s {}^2{S}_{1/2}$ , and $11d {}^2{D}_J$ levels in atomic cesium

   https://doi.org/10.1103/PhysRevA.105.022819  

   Quirk, Jonah A; Damitz, Amy; Tanner, Carol E; Elliott, D S (February 2022, Physical Review A)

   We report measurements of the absolute energies of the hyperfine components of the $$12s \ ^2S_{1/2}$$ and $$13s \ ^2S_{1/2}$$ levels of atomic cesium, $$^{133}$$Cs. Using the frequency difference between these components, we determine the hyperfine coupling constants for these states, and report these values with a relative uncertainty of $$\sim$$0.06\%. We also examine the hyperfine structure of the $$11d \ ^2D_{J}$$ ($J=3/2, 5/2$) states, and resolve the sign ambiguity of the hyperfine coupling constants from previous measurements of these states. We also derive new, high precision values for the state energies of the $$12s \ ^2S_{1/2}$$, $$13s \ ^2S_{1/2}$$ and $$11d \ ^2D_{J}$$ states of cesium. 

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4. One-jettiness DIS event shape at ${\mathrm{N}}^3\mathrm{LL}+\mathcal{O}\left({\alpha }_s^2\right)$

   https://doi.org/10.1103/PhysRevD.110.014045  

   Cao, Haotian; Kang, Zhong-Bo; Liu, Xiaohui; Mantry, Sonny (July 2024, Physical Review D)

   We present results for the ${\tau }_1$and ${\tau }_{1a}$1-jettiness global event shape distributions, for deep inelastic scattering (DIS), at the ${\mathrm{N}}^3\mathrm{LL}+\mathcal{O}\left({\alpha }_s^2\right)$level of accuracy. These event-shape distributions quantify and characterize the pattern of final state radiation in electron-nucleus collisions. They can be used as a probe of nuclear structure functions, as nuclear medium effects in jet production, and for a precision extraction of the QCD strong coupling. The results presented here, along with the corresponding numerical codes, can be used for analyses with HERA data, in Electron-Ion Collider (EIC) simulation studies, and for eventual comparison with real EIC data. Published by the American Physical Society2024 

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5. Optimizing fictitious states for Bell inequality violation in bipartite qubit systems with applications to the $t\overline{t}$ system

   https://doi.org/10.1103/PhysRevD.109.116005  

   Cheng, Kun; Han, Tao; Low, Matthew (June 2024, Physical Review D)

   There is a significant interest in testing quantum entanglement and Bell inequality violation in high-energy experiments. Since the analyses in high-energy experiments are performed with events statistically averaged over phase space, the states used to determine observables depend on the choice of coordinates through an event-dependent basis and are thus not genuine quantum states, but rather “fictitious states.” We find that the basis which diagonalizes the spin-spin correlations is optimal for constructing fictitious states to test the violation of Bell’s inequality. This result is applied directly to the bipartite qubit system of a top and antitop produced at a hadron collider. We show that the beam axis is the optimal basis choice near the $t\overline{t}$threshold production for measuring Bell inequality violation, while at high transverse momentum the basis that aligns along the momentum direction of the top is optimal. Published by the American Physical Society2024 

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