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#axions

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MPI für Radioastronomie

✨During the #Christmas season, we often think of #wonders and the invisible🪄 that connects our world. Did you know that scientists are searching for an invisible wonder - but in the #universe? 🌌 #Axions, the promising candidates for Dark Matter (DM)🖤, are ultra-light particles with masses around 10⁻²² eV and wavelengths of about one kiloparsec (~ 3x10¹⁶ km).

Particles with similar properties to axions are called "axion-like particles" (ALPs). 💡ALPs, which include ultra-light axions, can alter #light polarization – meaning the alignment of #lightwaves. During an internship with us, Sarah searched for such phenomena in low-frequency #LOFAR data 📡 from the pulsar PSR J0332+5434. Low frequencies📉 are ideal, as the ionosphere – an electron layer in the Earth's atmosphere 🌍, caused by solar radiation – creates interference that can be removed from low-frequency LOFAR data through calibration.

According to theories, axions apperars in strong magnetic fields, such as in #stellar cores, where they can escape because they interact very weakly with normal matter. Just like DM 🖤.

Similarly, pulsars have extremely strong static magnetic fields. When cosmic ALPs enter a strong #magneticfield, they can be converted into photons – that is, light 🌟 – and thus become detectable, if ultra-light axions exist.

Currently, there are three methods for searching for ALPs:
1️⃣ Helioscopes for solar ALPs (e.g. IAXO, 🖥️ 1) ☀️,
2️⃣ Haloscope searches in the galactic halo 🌌 (e.g. observing radiopulsars, 🖥️ 2), and
3️⃣ Generating ALPs in the lab 🔬 (e.g. ALPS II, @DESY , 🖥️ 3).
© S.Pappert, E.Moerova | MPIfR

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Ed Wiebe

The popular summary: "Axions, hypothetical particles posited as a source of dark matter, have eluded detection for decades due to their extremely weak interaction with light."

The actual summary: "#Axions, hypothetical particles posited as a source of #DarkMatter, have eluded detection for decades because they may not exist, but if they do the model has them interacting weakly with light."

journals.aps.org/prx/abstract/

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Scientific Frontline

#Axions are hypothetical elementary #particles that were initially postulated to solve a theoretical shortcoming of the strong interaction, the so-called strong CP problem. For many years, axions or axion-like particles (ALPs) have also been considered promising candidates for dark matter.
#Physics #sflorg
sflorg.com/2023/12/phy12112301

www.sflorg.comSearching for axions with the ATLAS detectorLatest measurements provide valuable information on novel particles that could explain the anomalous magnetic moment of the muon
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Daniel Fischer

Anomalies in Gravitational-Lensed Images Revealing Einstein Rings Modulated by Wavelike #DarkMatter: arxiv.org/abs/2304.09895 -> No WIMPS! Heavy particles don’t explain #GravitationalLensing oddities - detailed look at a lensed galaxy favors lighter particles called #axions: theconversation.com/new-look-a and arstechnica.com/science/2023/0

arXiv.orgAnomalies in Gravitational-Lensed Images Revealing Einstein Rings Modulated by Wavelike Dark MatterElucidating the nature of Dark Matter (DM), which does not interact with light and which interacts with known matter primarily or only through gravity, is one of the principal quests in physics. Leading candidates for DM are weakly interacting massive particles (WIMPs) or ultralight bosons (axions), at opposite extremes in mass scales, that have been postulated by competing theories to solve deficiencies in the Standard Model of particle physics. Whereas DM WIMPs behave like discrete particles ($\varrho$DM), quantum interference between DM axions is manifested as waves ($ψ$DM). Here, we show that gravitational lensing leaves signatures in multiply-lensed images of background galaxies that reveal whether the foreground lensing galaxy inhabits a $\varrho$DM or $ψ$DM halo. Whereas $\varrho$DM lens models leave well documented anomalies between the predicted and observed brightnesses and positions of multiply-lensed images, $ψ$DM lens models correctly predict the level of anomalies left over by $\varrho$DM lens models. More challengingly, when subjected to a battery of tests for reproducing the quadruply-lensed triplet images in the system HS 0810+2554, $ψ$DM is able to reproduce all aspects of this system whereas $\varrho$DM often fails. The growing success of $ψ$DM in reproducing astrophysical observations tilt the balance toward new physics invoking axions.
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