Searches for BSM physics at a gamma-gamma collider with Energy < $12$ GeV based on European XFEL

TL;DR

This paper explores the potential of a gamma-gamma collider extension of the European XFEL to detect BSM physics, specifically axion-like particles, in the 5-12 GeV energy range, using simplified and detailed beam dynamics models.

Contribution

It introduces the concept of using the XFEL beam dump as a photon-photon collider to search for BSM particles like ALPs in the 5-12 GeV range, combining simplified and comprehensive modeling approaches.

Findings

Potential to observe BSM processes such as ALPs in the 5-12 GeV range.

Feasibility of using the XFEL beam dump as a photon-photon collider.

Cross section estimates for ALP production at the proposed collider.

Abstract

The possibility of a Photon-Photon collider extension to the Beam dump of the $17.5$ GeV European XFEL has been discussed before as the first high energy collider of its sort. It would not just be to study the concept of photon colliders but would also be a collider without competition in the region of $5 - 12$ GeV for photon-photon collision. In this range, $b\overline{b}$ and $c\overline{c}$ resonances, tetraquarks as well as mesonic molecules can be observed. Furthermore, some BSM processes can also be reached in this range. In this paper we want to discuss the possibility of observing ALPs at such a collider. We will use a simplified description of the compton backscattering process to get a first look at cross sections and extend this to the full beam dynamics included prediction.