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1. Design of the ALPS II optical system

   https://doi.org/10.1016/j.dark.2022.100968  

   Diaz Ortiz, M.; Gleason, J.; Grote, H.; Hallal, A.; Hartman, M.T.; Hollis, H.; Isleif, K.-S.; James, A.; Karan, K.; Kozlowski, T.; et al (March 2022, Physics of the Dark Universe)
2. Design and performance of the ALPS II regeneration cavity

   https://doi.org/10.1364/OE.540297  

   Kozlowski, Todd; Wei, Li-Wei; Spector, Aaron_D; Hallal, Ayman; Frädrich, Henry; Brotherton, Daniel_C; Oceano, Isabella; Ejlli, Aldo; Grote, Hartmut; Hollis, Harold; et al (March 2025, Optics Express)

   The regeneration cavity (RC) is a critical component of the Any Light Particle Search II (ALPS II) experiment. It increases the signal from possible axions and axion-like particles in the experiment by nearly four orders of magnitude. The total round-trip optical losses of the power circulating in the cavity must be minimized in order to maximize the resonant enhancement of the cavity, which is an important figure of merit for ALPS II. Lower optical losses also increase the cavity storage time, and with the 123 meter long ALPS II RC we have demonstrated the longest storage time of a two-mirror optical cavity. We measured a storage time of 7.17±0.01ms, equivalent to a linewidth of 44.4 Hz and a finesse of 27,500 at a wavelength of 1064 nm. 

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3. The heterodyne sensing system for the ALPS II search for sub-eV weakly interacting particles

   https://doi.org/10.1016/j.dark.2021.100914  

   Hallal, Ayman; Messineo, Giuseppe; Ortiz, Mauricio Diaz; Gleason, Joseph; Hollis, Harold; Tanner, D.B.; Mueller, Guido; Spector, Aaron (March 2022, Physics of the Dark Universe)
4. Adiabatic conversion of ALPs into dark photon dark matter

   https://doi.org/10.1007/JHEP03(2025)215  

   Broadberry, Edward; Das, Saurav; Hook, Anson; Marques-Tavares, Gustavo (March 2025, Journal of High Energy Physics)

   A<sc>bstract</sc> We introduce a mechanism by which a misaligned ALP can be dynamically converted into a dark photon in the presence of a background magnetic field. An abundance of non-relativistic ALPs will convert to dark photons with momentum of order the inhomogeneities in the background field; therefore a highly homogeneous field will produce non-relativistic dark photons without relying on any redshifting of their momenta. Taking hidden sector magnetic fields produced by a first order phase transition, the mechanism can reproduce the relic abundance of dark matter for a wide range of dark photon masses down to 10⁻¹³eV. 

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5. Precise timing of MIS 7 substages from the Austrian Alps

   https://doi.org/10.5194/cp-17-1443-2021  

   Wendt, Kathleen A.; Li, Xianglei; Edwards, R. Lawrence; Cheng, Hai; Spötl, Christoph (January 2021, Climate of the Past)

   null (Ed.)

   Abstract. Investigating the precise timing of regional-scale climate changes during glacial terminations and the interglacial periods that follow is key tounraveling the mechanisms behind these global climate shifts. Here, we present a high-precision time series of climate changes in the Austrian Alpsthat coincide with the later portion of Termination III (TIII), the entire penultimate interglacial (Marine Isotope Stage (MIS) 7), Termination IIIa(TIIIa), and the penultimate glacial inception (MIS 7–6 transition). Using state-of-the-art mass spectrometry techniques, we have constructed auranium-series chronology with relative age uncertainties averaging 1.7 ‰ (2σ) for our study period (247 to 191 thousand yearsbefore present, ka). Results reveal the onset of warming in the Austrian Alps associated with TIII at 242.5 ± 0.2 ka and theduration of MIS 7e warming between 241.8 and 236.7 (±0.6) ka. An abrupt shift towards higher δ18O values at216.8 ka marks the onset of regional warming associated with TIIIa. Two periods of high δ18O values (greater than−10 ‰ Vienna Pee Dee Belemnite (VPDB)) between 215.9–213.3 and 204.3–197.5 (±0.4) ka coincide with interglacial substages MIS 7c and 7a,respectively. Multiple fluorescent inclusions suggest a partial retreat of the local Alpine glacier during peak obliquity forcings at214.3 ± 0.4 ka. Two newly collected stalagmites from Spannagel Cave (SPA146 and 183) provide high-resolution replications of thelatter portion of the MIS 7a-to-6e transition. The resulting multi-stalagmite record reveals important chronological constraints on climate shifts inthe Austrian Alps associated with MIS 7 while offering new insight into the timing of millennial-scale changes in the North Atlantic realm leadingup to TIII and TIIIa. 

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