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Related papers: Photon-ALP conversions inside AGN

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Many theories beyond the Standard Model of particle physics predict the existence of axionlike particles (ALPs) that mix with photons in the presence of a magnetic field. Searching for the effects of ALP-photon mixing in gamma-ray…

High Energy Astrophysical Phenomena · Physics 2023-04-24 James Davies , Manuel Meyer , Garret Cotter

Axion-like particles (ALPs) provide a compelling avenue for exploring physics beyond the Standard Model. In astrophysical magnetized plasmas an ALP-photon coupling $g_{a\gamma}$ induces energy-dependent oscillations in the photon survival…

High Energy Astrophysical Phenomena · Physics 2025-07-30 Yu Zhou , Jiejia Liu , Volodymyr Takhistov , Kazuhisa Mitsuda

Background radiation fields pervade the Universe, and above a certain energy any $\gamma$-ray flux emitted by an extragalactic source should be attenuated due to $e^+e^-$ pair production. The opacity could be alleviated if photons…

High Energy Astrophysical Phenomena · Physics 2014-09-05 Manuel Meyer , Daniele Montanino , Jan Conrad

Axion-Like Particles (ALPs) are predicted by many extensions of the Standard Model and give rise to characteristic dimming and polarization effects in a light beam travelling in a magnetic field. In this Letter, we demonstrate that…

Astrophysics · Physics 2008-11-26 Alessandro De Angelis , Oriana Mansutti , Marco Roncadelli

Oscillations between photons and axion-like particles (ALP) travelling in intergalactic magnetic fields have been invoked to explain a number of astrophysical phenomena, or used to constrain ALP properties using observations. One example is…

High Energy Astrophysical Phenomena · Physics 2016-06-15 Chen Wang , Dong Lai

Many extensions of the Standard Model of particle physics and in particular superstring and superbrane theories predict the existence of axion-like particles (ALPs). ALPs are very elusive, extremely light and interact primarily with…

High Energy Astrophysical Phenomena · Physics 2023-05-18 Giorgio Galanti , Marco Roncadelli , Fabrizio Tavecchio , Enrico Costa

In this review, we present a self-contained introduction to axion-like particles (ALPs) with a particular focus on their effects on photon polarization: both theoretical and phenomenological aspects are discussed. We derive the photon…

High Energy Physics - Phenomenology · Physics 2024-08-01 Giorgio Galanti

Axion-like particles (ALPs) and photons can quantum mechanically interconvert when propagating through magnetic fields, and ALP-photon conversion may induce oscillatory features in the spectra of astrophysical sources. We use deep (370 ks),…

High Energy Physics - Phenomenology · Physics 2017-12-27 M. C. David Marsh , Helen R. Russell , Andrew C. Fabian , Brian R. McNamara , Paul Nulsen , Christopher S. Reynolds

Photons couple to Axion-Like Particles (ALPs) or more generally to any pseudo Nambu-Goldstone boson in the presence of an external electromagnetic field. Mixing between photons and ALPs in the strong magnetic field of a Gamma-Ray Burst…

High Energy Astrophysical Phenomena · Physics 2011-03-18 Olga Mena , Soebur Razzaque , F. Villaescusa-Navarro

Axion-like particles (ALPs) and photons inter-convert in the presence of a magnetic field. At keV energies in the environment of galaxy clusters, the conversion probability can become unsuppressed for light ALPs. Conversion of thermal X-ray…

High Energy Physics - Phenomenology · Physics 2016-07-06 Joseph P. Conlon , M. C. David Marsh , Andrew J. Powell

Axion like particles (ALPs) are fundamental pseudo scalar particles with properties similar to Axions which are a well-known extension of the standard model to solve the strong CP problem in Quantum Chromodynamics. ALPs can oscillate into…

High Energy Astrophysical Phenomena · Physics 2017-10-30 Jhilik Majumdar , Francesca Calore , Dieter Horns

Coupling of axions or axion-like particles (ALPs) with photons may lead to photons escaping optically opaque regions by oscillating into ALPs. This phenomenon may be viewed as the Light Shining through Wall (LSW) scenario. While this LSW…

High Energy Physics - Phenomenology · Physics 2023-11-27 Dibya S. Chattopadhyay , Basudeb Dasgupta , Amol Dighe , Mayank Narang

The extragalactic background light (EBL) plays a crucial role in the propagation of high-energy particles throughout the Universe. In this work, we explore the impact of the EBL absorption effect on photon to axionlike particle (ALP)…

High Energy Physics - Phenomenology · Physics 2025-02-19 Hai-Jun Li , Wei Chao , Xiu-Hui Tan , Yu-Feng Zhou

The Axion Like Particle (ALP) is a hypothetical pseudo-scalar particle beyond the Standard Model, with a compelling possible connection to dark matter and early universe physics. ALPs can be converted into photons via interactions with…

High Energy Astrophysical Phenomena · Physics 2020-03-04 Ryo Yamamoto , Noriko Y. Yamasaki , Kazuhisa Mitsuda , Masahiro Takada

Axion-Like-Particles (ALPs) are hypothetical pseudo-scalar particles actively searched as light dark matter candidates. The coupling of ALPs to photons can give rise to distinctive spectral features in the observed gamma-ray spectrum of…

High Energy Astrophysical Phenomena · Physics 2026-03-13 Cervane Grimaud , Denys Malyshev , Emmanuel Moulin

The growing interest in axion-like particles (ALPs) stems from the fact that they provide successful theoretical explanations of physics phenomena, from the anomaly of the CP-symmetry conservation in strong interactions to the observation…

High Energy Astrophysical Phenomena · Physics 2021-06-08 Ivana Batković , Alessandro De Angelis , Michele Doro , Marina Manganaro

Due to their high magnetic fields and plasma densities, pulsars provide excellent laboratories for tests of beyond Standard Model (BSM) physics. When axions or axion-like particles (ALPs) approach closely enough to pulsars, they can be…

Cosmology and Nongalactic Astrophysics · Physics 2020-10-29 Anirudh Prabhu , Nicholas M. Rapidis

Axion-like particles (ALPs) provide a feasible explanation for the observed lower TeV opacity of the Universe. If the anomaly TeV transparency is caused by ALPs, then the fluxes of distant extragalactic sources will be enhanced at photon…

High Energy Astrophysical Phenomena · Physics 2021-11-17 Yun-Feng Liang , Xing-Fu Zhang , Ji-Gui Cheng , Hou-Dun Zeng , Yi-Zhong Fan , En-Wei Liang

Well-motivated extensions of the standard model predict ultra-light and fundamental pseudo-scalar particles (e.g., axions or axion-like particles: ALPs). Similarly to the Primakoff-effect for axions, ALPs can mix with photons and…

High Energy Physics - Phenomenology · Physics 2018-05-02 Jhilik Majumdar , Francesca Calore , Dieter Horns

Hypothetical axion-like particles (ALPs) are of interest because of their potential to act as dark matter or to reveal information about yet undiscovered fundamental constituents of matter. Such particles can be created when photons…

High Energy Astrophysical Phenomena · Physics 2025-08-19 Denys Malyshev , Lidiia Zadorozhna , Yuriy Bidasyuk , Andrea Santangelo , Oleg Ruchayskiy