XENON Collaboration2021-10-192021-10-192019XENON Collaboration. "First Results on the Scalar WIMP-Pion Coupling, Using the XENON1T Experiment." <i>Physical Review Letters,</i> 122, no. 7 (2019) American Physical Society: https://doi.org/10.1103/PhysRevLett.122.071301.https://hdl.handle.net/1911/111562We present first results on the scalar coupling of weakly interacting massive particles (WIMPs) to pions from 1 t yr of exposure with the XENON1T experiment. This interaction is generated when the WIMP couples to a virtual pion exchanged between the nucleons in a nucleus. In contrast to most nonrelativistic operators, these pion-exchange currents can be coherently enhanced by the total number of nucleons and therefore may dominate in scenarios where spin-independent WIMP-nucleon interactions are suppressed. Moreover, for natural values of the couplings, they dominate over the spin-dependent channel due to their coherence in the nucleus. Using the signal model of this new WIMP-pion channel, no significant excess is found, leading to an upper limit cross section of 6.4×10−46 cm2 (90% confidence level) at 30 GeV/c2 WIMP mass.engPublished by the American Physical Society under the terms of the Creative Commons Attribution 4.0 International license. Further distribution of this work must maintain attribution to the author(s) and the published article’s title, journal citation, and DOI.Journal articlePhysRevLett-122-071301https://doi.org/10.1103/PhysRevLett.122.071301