Abstract
The Gamma Factory is a proposal to back-scatter laser photons off a beam of partially-stripped ions at the LHC, producing a beam of $\sim 10$ MeV to $1$ GeV photons with intensities of $10^{16}$ to $10^{18}~\text{s}^{-1}$. This implies $\sim 10^{23}$ to $10^{25}$ photons on target per year, many orders of magnitude greater than existing accelerator light sources and also far greater than all current and planned electron and proton fixed target experiments. We determine the Gamma Factory's discovery potential through "dark Compton scattering," $\gamma e \to e X$, where $X$ is a new, weakly-interacting particle. For dark photons and other new gauge bosons with masses in the 1~to~100 MeV range, the Gamma Factory has the potential to discover extremely weakly-interacting particles with just a few hours of data and will probe couplings as low as $\sim 10^{-9}$ with a year of running. The Gamma Factory therefore may probe couplings lower than all other terrestrial experiments and is highly complementary to astrophysical probes. We outline the requirements of an experiment to realize this potential and determine the sensitivity reach for various experimental configurations.
Highlights
The search for new light and weakly interacting particles is currently an area of great interest [1,2]
By exploiting the Large Hadron Collider (LHC)’s ability to accelerate partially stripped ions to Lorentz factors of γ ∼ 200–3000, ∼10 eV photons can be back-scattered to 10 MeV to GeV energies, sufficient to search for new particles with masses in the 1–100 MeV mass range
We have investigated for the first time the potential of the gamma factory (GF) to discover new particles through dark Compton scattering, γe → eX, where X is a dark photon, anomaly-free gauge boson, dark Higgs boson, or dark pseudoscalar
Summary
The search for new light and weakly interacting particles is currently an area of great interest [1,2]. Using the same principle that governs radar guns, the laser light is Doppler shifted twice to energies These energies are well-matched to the MeV to GeV mass range for new, weakly interacting particles. In all of the gauge boson cases, we find that dark Compton scattering at the GF has significant discovery prospects, probing regions of parameter space with masses mX ∼ 1 to 100 MeV and couplings ε ∼ 10−9 to 10−4, where the low-ε part of the range extends to values far lower than all other terrestrial experiments. The GF is complementary to other ongoing and proposed experiments that make use of the LHC to search for weakly interacting particles [13,14,15,16,17,18,19,20], and our results provide a significant new physics case for the GF, supplementing existing SM and beyond the SM motivations [10,21,22,23]
Sign-in/Register to view highlights & summary Sign-in/Register to access full text options 
Free) 
Talk to us
Join us for a 30 min session where you can share your feedback and ask us any queries you have
Schedule a call
