A Proposal for the Lohengrin Experiment to Search for Dark Sector Particles at the ELSA Accelerator

Philip Bechtle; Christian Bespin; Dominique Breton; Carlos Orero Canet; Klaus Desch; Herbi Dreiner; Oliver Freyermuth; Rhorry Gauld; Markus Gruber; César Blanch Gutiérrez; Hazem Hajjar; Matthias Hamer; Jan-Eric Heinrichs; Adrian Irles; Jochen Kaminski; Laney Klipphahn; Hans Krüger; Michael Lupberger; Jihane Maalmi; Dennis Proft; Roman Pöschl; Leonie Richarz; Tobias Schiffer; Patrick Schwäbig; Martin Schürmann; Dirk Zerwas

arXiv · 2410.10956

A Proposal for the Lohengrin Experiment to Search for Dark Sector Particles at the ELSA Accelerator

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Abstract

We present a proposal for a future light dark matter search experiment at the Electron Stretcher Accelerator ELSA in Bonn: Lohengrin. It employs the fixed-target missing momentum based technique for searching for dark-sector particles. The Lohengrin experiment uses a high intensity electron beam that is shot onto a thin target to produce mainly SM bremsstrahlung and - in rare occasions - possibly new particles coupling feebly to the electron. A well motivated candidate for such a new particle is the dark photon, a new massive gauge boson arising from a new gauge interaction in a dark sector and mixing kinetically with the standard model photon. The Lohengrin experiment is estimated to reach sensitivity to couplings small enough to explain the relic abundance of dark matter in various models for dark photon masses between approximately 1 MeV and approximately 100 MeV.

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Philip Bechtle, Christian Bespin, Dominique Breton, Carlos Orero Canet, Klaus Desch, Herbi Dreiner, Oliver Freyermuth, Rhorry Gauld, Markus Gruber, César Blanch Gutiérrez, Hazem Hajjar, Matthias Hamer, Jan-Eric Heinrichs, Adrian Irles, Jochen Kaminski, Laney Klipphahn, Hans Krüger, Michael Lupberger, Jihane Maalmi, Dennis Proft, Roman Pöschl, Leonie Richarz, Tobias Schiffer, Patrick Schwäbig, Martin Schürmann, Dirk Zerwas. 2025-04-28. A Proposal for the Lohengrin Experiment to Search for Dark Sector Particles at the ELSA Accelerator. https://arxiv.org/abs/2410.10956

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