Year: 2025
Type: article
Abstract: The link between Standard Model (SM) particles and dark matter (DM) can be introduced via spin-2 massive mediator, $$ {\text {G}}$$ G , that couples to photon and charged leptons. Moreover, in a mediator mass range from sub-MeV to sub-GeV, fixed-target facilities such as NA64e, LDMX, NA64 $$\mu $$ μ , $$\hbox {M}^3$$ M 3 , and E137, can potentially probe such particle of the hidden sector via the signatures that are described by the bremsstrahlung-like process involving tensor mediator. We compare numerically the Weizsaker–Williams (WW) approximation and the exact tree-level (ETL) method for the bremsstrahlung-like mediator production cross section by choosing various parameters of the fixed-target experiments. To be more specific, the determination of WW validity region (in the parameter space of spin-2 DM mediator scenario, that can be examined in the laboratory facilities) is of particular interest of the present manuscript. In addition, we derive novel constraints on spin-2 DM mediator parameter space from the data of the E137 fixed-target experiment. In particular, we demonstrate that the E137 experiment has been ruled out the couplings of the spin-2 mediator at the level of $$8~\times ~10^{-8}~\text{ GeV}^{-1}~\lesssim ~c^{\text {G}}_{ee}~\lesssim ~10^{-5}~\text{ GeV}^{-1}$$ 8 × 10 - 8 GeV - 1 ≲ c ee G ≲ 10 - 5 GeV - 1 for the typical masses in the range $$100~\text{ MeV }~\lesssim ~m_{\text {G}}~\lesssim 800~\text{ MeV }$$ 100 MeV ≲ m G ≲ 800 MeV , that corresponds to the statistics of $$1.87~\times ~10^{20}$$ 1.87 × 10 20 electrons accumulated on target. The latter implies its universal coupling to photons and electrons, $$c^{\textrm{G}}_{\gamma \gamma }~=~c^{\textrm{G}}_{ee}$$ c γ γ G = c ee G .
Source: The European Physical Journal C
Authors: I. Voronchikhin, D. Kirpichnikov
Language: English
Subfield: Nuclear and High Energy Physics
Field: Physics and Astronomy
Domain: Physical Sciences
Open Access status: diamond
Funder: Russian Science Foundation
Award: G5394013039
OpenAlex ID: W4414926674