Dark Photon Search

The standard model of particle physics as well as cosmology are very successful theories. In these days, we know that dark matter must exist. Its properties and how to fit it into the Standard Model are some of the most pressing questions in elementary particle physics.

We are developing an experimental strategy for finding a particle that could explain these questions - the dark photon. It serves as a portal between the currently known Standard Model and a "dark sector" that may contain a variety of dark matter particles. The discovery of a dark photon would have implications for the general understanding of elementary particle physics.

The goal of the strategy is to consider the properties of the institute's own electron accelerator ELSA and to even realize the experiment in Bonn.

© Jan-Eric Heinrichs

In order to develop an experimental strategy, it is important to have complete detector simulation. This allows the detector response to be simulated and evaluated for all processes of interest. Finally, it is possible to estimate the sensitivity of the experimental approach by simulations and to compare different approaches.

Before the construction, the goal is to estimate with which sensitivity the experiment can exclude a potential model for a dark sector with dark photons as portal intercation.

© Frank Frommberger

The Institute operates its own electron accelerator ELSA (see also ELSA website). There are several features that make ELSA interesting for a potential experiment to search for dark photons.

Among these are the low energy uncertainty of the electron beam and the energy range suitable for the experiment. In addition, electrons can be resonantly extracted from the beam in ELSA. It is thus possible to produce bunches of very few electrons. This is particularly advantageous for the demanding tracking of the experiment.

© Jan-Eric Heinrichs
© Jan-Eric Heinrichs
© Jan-Eric Heinrichs

The basic experimental strategy is based on a proposal of the LDMX Collaboration. A controlled electron beam is fired at a fixed target (fixed target experiment). Interactions with the target material lead to e.g. bremsstrahlung. In the case of potential dark photons also dark bremsstrahlung which is  characterized by the fact that a considerable  part of the radiation energy is carried out of the experiment by the mass of the dark photons. Re-interaction of a dark photon or a particle from the dark sector with the detector is very unlikely.

Thus, with the trackers and the calorimeter, the searches focus on  interactions with substantial transverse momentum and missing energy.

Further Information and Links

There are redirections to a quite detailed whitepaper of the LDMX Collaboration, as well as to an information page of Lund University and to the Bethe Center for Theoretical Particle Physics (BCTP).

  •  In the whitepaper, many concepts are explained in more detail than it is possible within the scope of this web page.
  • Lund University presents a conceptually similar experiment on their website as well as some complementary information.
  • Our efforts for the design of the experiment are supported on the theoretical side by the Bethe Center for Theoretical Physics.


Wird geladen