Dark sector-photon interactions in proton-beam experiments

Abstract

We consider electromagnetically neutral dark states that couple to the photon through higher dimensional effective operators, such as electric and magnetic dipole moment, anapole moment and charge radius operators. We investigate the possibility of probing the existence of such dark states, taking a Dirac fermion χ as an example, at several representative proton-beam experiments. As no positive signal has been reported, we obtain upper limits (or projected sensitivities) on the corresponding electromagnetic form factors for dark states lighter than several GeV. We demonstrate that while the current limits from proton-beam experiments are at most comparable with those from high-energy electron colliders, future experiments, such as DUNE and SHiP, will be able to improve the sensitivities to electric and magnetic dipole moment interactions, owing to their high intensity.

The Forward Physics Facility: Sites, Experiments, and Physics Potential

“…In addition to mCPs, there are a variety of other models that could lead to an anomalous energy deposition signature that could be probed at FPF experiments, such as models of DM with electromagnetic form factors [148,149].…”

Light and darkness: consistently coupling dark matter to photons via effective operators

“…Furthermore, the dark matter mass itself is a free parameter and determines the relevant scale for thermal freeze-out and indirect detection constraints. Electromagnetic form factors for dark matter have been considered in direct and indirect detection as well as at colliders over several decades of dark matter mass, extending into the TeV range [8][9][10][25][26][27][28][29][30][31][32][33][34][35][36][37][38]. However, it is clear that the hypercharge form factors should be the appropriate EFT here, given that relevant energies can far exceed the electroweak scale.…”

Dark matter electromagnetic dipoles: the WIMP expectation

“…An interesting possibility to improve the direct detection sensitivity in such cases stems fom the fact that WIMPs might have electromagnetic dipole moments. In fact, various electromagnetic form factors (electric/magnetic dipoles, anapole, charged radius) of WIMPs have been considered in the literature [13][14][15][16][17][18][19][20][21][22][23][24][25][26][27][28][29][30][31][32]. Early studies [17][18][19][20]24] considered them as a solution to resolve the discrepancy between DAMA/CoGeNT signals and null results of other DM searches, though this has been since then well excluded.…”

“…Beyond the WIMP regime, there has been growing interest in electromagnetic dipoles of sub-GeV DM due to potential connections with CMB/LSS observations, stellar physics, and the intensity frontier searches-see, e.g.,[29][30][31][32].…”