Limits on the spin-dependent WIMP-nucleon cross-sections from the first science run of the ZEPLIN-III experiment
V. N. Lebedenko, H. M. Araujo, E. J. Barnes, A. Bewick, R. Cashmore, V. Chepel, D. Davidge, J. Dawson, T. Durkin, B. Edwards, C. Ghag, V. Graffagnino, M. Horn, A. S. Howard, A. J. Hughes, W. G. Jones, M. Joshi, G. E. Kalmus, A. G. Kovalenko, A. Lindote, I. Liubarsky, M. I. Lopes, R. Luscher, K. Lyons, P. Majewski, A. StJ. Murphy, F. Neves, J. Pinto da Cunha, R. Preece, J. J. Quenby, P. R. Scovell, C. Silva, V. N. Solovov, N. J. T. Smith, P. F. Smith, V. N. Stekhanov, T. J. Sumner, C. Thorne, R. J. Walker
TL;DR
Analysis of data from the first science run of ZEPLIN-III, a two-phase xenon experiment searching for galactic dark matter weakly interacting massive particles based at the Boulby mine, indicates that the sensitivity of xenon targets to the spin-dependent WIMP-proton interaction could be much lower than implied by previous calculations.
Abstract
We present new experimental constraints on the WIMP-nucleon spin-dependent elastic cross-sections using data from the first science run of ZEPLIN-III, a two-phase xenon experiment searching for galactic dark matter WIMPs based at the Boulby mine. Analysis of $\sim$450 kg$\cdot$days fiducial exposure revealed a most likely signal of zero events, leading to a 90%-confidence upper limit on the pure WIMP-neutron cross-section of $σ_n=1.8\times 10^{-2}$ pb at 55 GeV/$c^2$ WIMP mass. Recent calculations of the nuclear spin structure based on the Bonn CD nucleon-nucleon potential were used for the odd-neutron isotopes $^{129}$Xe and $^{131}$Xe. These indicate that the sensitivity of xenon targets to the spin-dependent WIMP-proton interaction is much lower than implied by previous calculations, whereas the WIMP-neutron sensitivity is impaired only by a factor of $\sim$2.