https://doi.org/10.1140/epjc/s10052-025-14868-6
Regular Article - Theoretical Physics
The bremsstrahlung-like production of the massive spin-2 dark matter mediator
1
Tomsk Polytechnic University, 634050, Tomsk, Russia
2
Institute for Nuclear Research, 117312, Moscow, Russia
a
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Received:
13
August
2025
Accepted:
28
September
2025
Published online:
8
October
2025
Abstract
The link between Standard Model (SM) particles and dark matter (DM) can be introduced via spin-2 massive mediator, 
, 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
, 
, 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 
for the typical masses in the range 
, that corresponds to the statistics of 
electrons accumulated on target. The latter implies its universal coupling to photons and electrons, 
.
© The Author(s) 2025
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Funded by SCOAP3.
