BEGIN:VCALENDAR VERSION:2.0 PRODID:-//CERN//INDICO//EN BEGIN:VEVENT SUMMARY:Newsletter March 2026 DTSTART:20260325T090000Z DTEND:20260325T110000Z DTSTAMP:20260503T013300Z UID:indico-event-51559@agenda.infn.it DESCRIPTION:This is March’s edition of the newsletter of the COST action . The aim is to keep you updated on recent and upcoming conferences and po stdoc positions on subjects related to WISPs.\n \nCosmic Wispers preprint s\n \nBlack hole scalar sirens in the Milky Way\nDaniel Gavilan-Martin\, Olivier Simon\, Dhashin Krishna\, Derek F. Jackson Kimball\, Dmitry Budker \, Arne Wickenbrock\nhttps://arxiv.org/abs/2602.23415\nLight scalar partic les trigger the superradiant instability around spinning black holes (BHs) \, causing clouds of scalars to grow around the BH. In the presence of suf ficiently strong particle self-interactions\, scalars are ejected from BH orbits\, resulting in coherent\, non-relativistic emissions that continuou sly carry away the BH's angular momentum. Parameters exist for which cloud growth is much faster\, and scalar depletion is much slower\, than the ag e of the Galaxy. This defines a distinct class of astrophysical sources of scalars\, which we call BH scalar sirens -- BHs that persistently emit sc alars effectively forever. We compute the scalar background from the expec ted population of isolated stellar-mass BHs in the Milky Way. This provide s a detection target independent of early-universe scalar production or co smological initial conditions. The generated observable signals are up to two orders-of-magnitude larger than those expected from a misaligned cosmi c scalar.  While stellar-mass Milky Way BHs are our primary target\, our framework extends to supermassive\, intermediate-mass and light BHs. Given the difficulty of directly observing populations of isolated BHs\, scalar emissions offer a novel probe of these otherwise invisible objects\, high lighting the potential for joint discovery between scalars and BHs\, and b roadly motivating searches for scalars over many orders-of-magnitude in ma ss.\n\nAxions at the meV Crossroads: Theory\, Cosmology\, Astrophysics\, a nd Experiments\nMichele Cicoli\, Francesco D'Eramo\, Luca Di Luzio\, Damia no F. G. Fiorillo\, Maurizio Giannotti\, Alicia Gomez\, Diego Guadagnoli\, Mathieu Kaltschmidt\, Bradley J. Kavanagh\, Alessandro Lella\, Giuseppe L ucente\, David J. E. Marsh\, Federico Mescia\, Alessandro Mirizzi\, Javier Redondo\, Nicole Righi\, Jaime Ruz\, Ken'ichi Saikawa\, Elisa Todarello\, Edoardo Vitagliano\, Su-Yang Xu\nhttps://arxiv.org/abs/2603.18167\nThe me V mass range has emerged as a focal point in axion physics\, where advance s in theory\, cosmology\, astrophysics\, and experimental techniques conve rge. Axions in this mass range are theoretically well motivated\, can aris e in ultraviolet-complete models\, and can have significant cosmological i mpacts as dark matter or dark radiation. In parallel\, their efficient pro duction in stellar and supernova environments provides powerful astrophysi cal probes. Here\, we provide a comprehensive overview of meV axions acros s these domains\, highlighting both established results and open questions . We discuss the theoretical underpinnings of meV axions\, their cosmologi cal and astrophysical signatures\, and the diverse experimental strategies -- ranging from helioscopes and haloscopes to quasiparticle systems and l arge-volume Cherenkov detectors -- that aim to explore this regime. The co nvergence of these approaches emphasizes the pivotal role of the meV mass range for axion discovery in the coming years\, identifying meV axions as a key probe for testing beyond-Standard-Model physics. This review documen t is the direct outcome of the discussions at the dedicated workshop "The meV Mass Axion Frontier: Challenges and Opportunities"\, held at Laborator i Nazionali di Frascati (IT) on 27--28 October 2025\, and organized by the EU funded COST Action "Cosmic WISPers in the Dark Universe: Theory\, astr ophysics\, and experiments" (CA21106). Its aim is to provide an overview o f current efforts in meV axion research\, their motivations\, and the rese arch goals that animate the community involved in this search.\n\nThe COSM IC WISPers White Paper: The physics case for Weakly Interacting Slim Parti cles\nAriel Arza et al.\nhttps://arxiv.org/abs/2603.03433\nAxions and othe r very weakly interacting slim particles (WISPs)\, with masses below 1 GeV \, arise naturally in many extensions of the Standard Model of particle ph ysics. In particular\, they could offer a new framework to explain the nat ure of dark matter and may help address a range of puzzling observations i n astrophysics and particle physics. This review provides an overview of o ngoing WISP searches and outlines the prospects for the next decade\, span ning their theoretical motivation\, indirect signatures in astrophysical o bservations\, and dedicated laboratory experiments. It is based on the wor k carried on by the EU-funded COST Action ``Cosmic WISPers in the Dark Uni verse: Theory\, astrophysics\, and experiments'' (CA21106). This network p lays a key role in coordinating and supporting WISP searches across Europe \, while also contributing to the development of a roadmap aimed at securi ng European leadership in this research area. It is emphasized that Europe is currently pursuing a rich\, diverse\, and cost-effective experimental program\, with the potential to deliver one or more transformative discove ries.\n \nWe encourage participants in the COST action to send us a small summary\, typically smaller than the abstract\, of their own articles tha t will appear in the arXiv (after they appear\, with their arXiv numbers). The summary will be disseminated in the newsletter.\nSend email to \nAle ssandro Lella alessandro.lella@unipd.it\nDamiano Fiorillo damianofg@gmail. com\nwith subject: preprint summary for Cosmic WISPers newsletter.\n\nPhD/ Postdoc/Junior Positions\n\n\nMarch\n\n\n\nPostdoctoral positions\, Univer sity of Minnesota\, Minneapolis link\n\n\n\nApril\n\n\n\nPostdoctoral posi tions in supernova neutrino physics\, Beijing link\n\n\nPostdoctoral posit ions for cosmic exotic particle search\, USTC\, Hefei link\n\n\n\nMay\n\n\ n\nPhD positions in Astrophysics\, Cosmology and Gravitation\, Espirito Sa nto University\, South America. link\n\n\n\nAugust\n\n\n\nPostdoctoral res earcher positions in theoretical astroparticle physics and axion phenomeno logy\, Annecy LAPTH link\n\n\n\n\nConferences\n\n\nMarch\n\n\n\nGGI PhD Sc hool on "Theoretical Aspects of Astroparticle Physics\, Cosmology and Grav itation" link\n\n\n60th Rencontres de Moriond on Very High Energy Phenomen a in the Universe: Moriond VHEPU 2026 link\n\n\n2nd UNDARK School link\n\n \n\nApril\n\n\n\n7th Edition of the international conference Progress on O ld and New Themes in cosmology (PONT 2026) link\n\n\nDark Energy from Home 2026 (DEfH26) link\n\n\n\nMay\n\n\n\nUniVersum VII -- Naples 2026 link\n\ n\nSCALE 2026: Strings & Cosmology – All Lengths Explored (SCALE) link\n \n\nPlanck2026 & 6th EuCAPT Symposium link\n\n\n6th New Physics Opportunit ies at Neutrino Facilities Workshop (NPN 2026) link\n\n\n\nJune\n\n\n\n16t h International Workshop on the Identification of Dark Matter 2026 (IDM 20 26) link\n\n\n32nd International Conference on Neutrino Physics and Astrop hysics (Neutrino 2026) link\n\n\nPASCOS 2026: The 31st International Sympo sium on Particles\, Strings\, and Cosmology (PASCOS2026) link\n\n\nBlack H oles & Cosmology 2026 (BHCos26) link\n\n\n4th Training School of the COST Action CA21106: Cosmic WISPers link\n\n\n4th General Meeting of the COST A ction: Cosmic WISPers (CA21106) link\n\n\nPrimordial Cosmology: Novel Pers pectives from Scattering Amplitudes\, Holography and the Bootstrap link\n\ n\n\nJuly\n\n\n\nExploring New Frontiers in Cosmology: GGI Workshop link\n \n\nDark Matter and Stars: Multi-Messenger Probes of Dark Matter and Modif ied Gravity (icdms2026) link\n\n\nAxions in Seoul 2026: Frontiers in Theor y\, Cosmology\, and Experiment (AiS 2026) link\n\n\nNew Frontiers in Stron g gravity link\n\n\n\nAugust\n\n\n\nXVI International Conference on Gravit ation\, Astrophysics and Cosmology (ICGAC16) link\n\n\nInvisibles 26 link\ n\n\nListening to the Cosmos: New Frontiers in Gravitational Wave Physics link\n\n\nCOSMO-26: 29th International Conference on Particle Physics & Co smology link\n\n\nNeutrino Oscillation Workshop 2026 (NOW 2026) link\n\n\n \nSeptember\n\n\n\nErice International School/Workshop of Nuclear Physics\ , 47th course on 'Neutrinos in Cosmology\, in Astro-\, Particle- and Nucle ar Physics' link\n\n\n\nNovember\n\n\n\n21st Patras Workshop on Axions\, W IMPs and WISPs link\n\n\n\nDecember\n\n\n\n4th International Conference on Neutrinos and Dark Matter (NuDM- 2026) link\n\n\n\n\n\nhttps://agenda.inf n.it/event/51559/ URL:https://agenda.infn.it/event/51559/ END:VEVENT END:VCALENDAR