Search for an invisibly decaying Higgs boson or dark matter candidates produced in association with a <math xmlns="http://www.w3.org/1998/Math/MathML">
  <mi>Z</mi>
</math> boson in <math xmlns="http://www.w3.org/1998/Math/MathML">
  <mi>p</mi>
  <mi>p</mi>
</math> collisions at <math xmlns="http://www.w3.org/1998/Math/MathML">
  <msqrt>
    <mi>s</mi>
  </msqrt>
  <mo>=</mo>
</math> 13 TeV with the ATLAS detector
OSTI OAI (U.S. Department of Energy Office of Scientific and Technical Information)