Dark-field Search for Quantum Vacuum Signals in the Low-Energy Regime
We report on the experimental details of a dark-field search for light-by-light scattering signals performed at the High Energy Density (HED) instrument of the European XFEL (EuXFEL) in a pump-probe type experiment colliding the EuXFEL beam with the 300-TW-class near-infrared Relativistic Laser at XFEL (ReLaX) at a center-of-mass photon energy of $ω_\star = 116\,\mathrm{eV}$. Especially in combination with polarization filtering, the dark-field concept allows the signal-to-background ratio to be significantly enhanced and both polarization channels to be recorded. This work elaborates on the experimental setup and the diagnostics used, from the per-shot spatiotemporal-overlap diagnostics, via the polarizing beam splitter, to the characterization of the residual background. Moreover, it provides details on the start-to-end simulations of the setup used for analysis. Accumulating 2751 pump-probe collisions, no excess above background is observed, and an upper limit on the light-by-light scattering cross section of $7\times10^{4}$ times the QED prediction at a 95% confidence level is derived. This is the most stringent bound on low-energy light-by-light scattering achieved to date, representing an improvement by ten orders of magnitude upon previous experimental limits.
Authors
- Rafael Celestre (ORCID: https://orcid.org/0000-0001-9398-4114)
- Pooyan Khademi (ORCID: https://orcid.org/0000-0003-0818-4134)
- Vojtěch Vozda (ORCID: https://orcid.org/0000-0002-5426-1519)
- T. Toncian (ORCID: https://orcid.org/0000-0001-7986-3631)
- J. Chalupský (ORCID: https://orcid.org/0000-0001-6930-1774)
- Willi Hippler (ORCID: https://orcid.org/0009-0007-9144-6268)
- Hauke Höppner (ORCID: https://orcid.org/0009-0000-1929-5097)
- M. Nakatsutsumi (ORCID: https://orcid.org/0000-0003-0868-4745)
- F. C. Salgado (ORCID: https://orcid.org/0000-0002-9109-9370)
- Georgiy Shoulga (ORCID: https://orcid.org/0000-0001-6580-9327)
- V. Hájková (ORCID: https://orcid.org/0000-0002-0776-6012)
- Thomas R. Preston (ORCID: https://orcid.org/0000-0003-1228-2263)
- Roland A. Sauerbrey
- Jan Wild (ORCID: https://orcid.org/0000-0003-2216-2898)
- Aimé Matheron (ORCID: https://orcid.org/0000-0003-4621-260X)
- Carsten Baehtz (ORCID: https://orcid.org/0000-0003-1480-511X)
- J. Grenzer
- T. E. Cowan (ORCID: https://orcid.org/0000-0002-5845-000X)
- G. G. Paulus (ORCID: https://orcid.org/0000-0002-8343-8811)
- Frank Seiboth (ORCID: https://orcid.org/0000-0002-2795-1338)
- Felix Karbstein (ORCID: https://orcid.org/0000-0003-2239-1789)
- V. Bouffetier (ORCID: https://orcid.org/0000-0001-6079-1260)
- Šimon Jelínek (ORCID: https://orcid.org/0000-0002-1999-811X)
- E. Brambrink (ORCID: https://orcid.org/0009-0004-2404-9412)
- Michał Andrzejewski (ORCID: https://orcid.org/0000-0001-8997-8301)
- Travis Griffin
- U. Zastrau (ORCID: https://orcid.org/0000-0002-3575-4449)
- M. Toncian (ORCID: https://orcid.org/0009-0005-5863-1934)
- R. Lötzsch
- Hans-Peter Schlenvoigt (ORCID: https://orcid.org/0000-0003-4400-1315)
- M. Masruri (ORCID: https://orcid.org/0000-0002-2521-6241)
- Isabella Probst
- Sebastian Göde (ORCID: https://orcid.org/0009-0006-5266-9154)
- Matt Zepf
- Oliver Humphries
- Alexander Sävert (ORCID: https://orcid.org/0009-0004-1949-8969)
- Jakub Bulička (ORCID: https://orcid.org/0009-0009-1046-8014)
- Alzbeta Horynova (ORCID: https://orcid.org/0009-0008-4930-0844)
- Sripati V. Rahul
- Libor Juha
- Lingen Huang (ORCID: https://orcid.org/0000-0003-1184-2097)
- Thomas Roth (ORCID: https://orcid.org/0000-0003-4937-1067)
- Nikita Medvedev
- Sergey Antipov
- Abha Thazhathe Peedika
- Alejandro Laso-García
- Edgar Weckert
- Jan Patrick Schwinkendorf
- Peter Hilz
- Colin Wessel
- Samuele Di Dio Cafiso
- Minxue Tang
- Michal Šmíd
- Jens Hauser
- Jennifer Popp
Publication Details
- Journal
- arXiv (Cornell University)
- Published
- 2026-10-29
- DOI
- https://doi.org/10.48550/arxiv.2610.39867
- Primary Topic
- Quantum Electrodynamics and Casimir Effect
- Type
- preprint