Graphene-based super-light invisible matter particle search

We propose a new dark-matter detection strategy that will potentially enable the search for super-light dark matter <a:math xmlns:a="http://www.w3.org/1998/Math/MathML" display="inline"><a:mrow><a:msub><a:mrow><a:mi>m</a:mi></a:mrow><a:mrow><a:mi>χ</a:mi></a:mrow></a:msub><a:mo>≃</a:mo><a:mn>0.1</a:mn><a:mtext> </a:mtext><a:mtext> </a:mtext><a:mi>keV</a:mi></a:mrow></a:math>, improving the minimum detectable mass by more than 3 orders of magnitude compared to ongoing experiments. This can be achieved by intimately integrating the target material, specifically the <c:math xmlns:c="http://www.w3.org/1998/Math/MathML" display="inline"><c:mi>π</c:mi></c:math>-bond electrons in graphene, into a Josephson junction to create a highly sensitive detector capable of detecting energy deposits from dark matter as small as <e:math xmlns:e="http://www.w3.org/1998/Math/MathML" display="inline"><e:mrow><e:mo>∼</e:mo><e:mn>0.1</e:mn><e:mtext> </e:mtext><e:mtext> </e:mtext><e:mi>meV</e:mi></e:mrow></e:math>. We investigate detection prospects of pg-, ng-, and <g:math xmlns:g="http://www.w3.org/1998/Math/MathML" display="inline"><g:mrow><g:mi mathvariant="normal">μ</g:mi><g:mi mathvariant="normal">g</g:mi><g:mtext>−</g:mtext><g:mi>scale</g:mi></g:mrow></g:math> detectors by calculating the scattering rate between dark matter and free electrons confined in two-dimensional graphene, including Pauli-blocking factors and in-medium screening effects. We find that the proposed detector is expected to not only serve as a complementary probe of superlight dark matter but also achieve higher experimental sensitivities than other proposed experiments, assuming zero readout noise, thanks to the extremely low threshold energy of our graphene Josephson junction sensor.