• Physics 15, s169
A superconducting nanowire detector locations new bounds on how a hypothetical light-weight darkish matter particle interacts with electrons.
Hunting for lightweight dark matter particles requires detectors with much lower signal thresholds than traditional experiments. This requirement has prompted novel detection techniques, including probing the faint interactions that occur between sub-MeV particles and electrons. In a 180-hour-long experiment, Yonit Hochberg of the Hebrew University of Jerusalem and her colleagues demonstrate a device that distinguishes hypothetical sub-MeV dark matter from background noise with record sensitivity . Their experiment locations the strongest constraints but on interactions between light-weight darkish matter and common matter.
Hochberg and her colleagues etched an array of nanowires in a 7-nm-thick tungsten-silicide movie to provide a superconducting nanowire single-photon detector, a sensor that’s delicate to extraordinarily small power inputs. When power above some threshold is deposited on a superconducting nanowire, the wire briefly turns into an everyday conductor, leading to a voltage pulse.
The staff circulated a hard and fast present by means of their gadget and sealed it in a light-tight field for 180 hours. They counted 4 voltage pulses, every similar to a deposited power of at the very least 0.73 eV. Absent every other detectable power supply, these darkish counts could possibly be attributed to cosmic-ray-generated muons or high-energy particles excited by radioactive decay.
To distinguish such background sources from interactions between sub-MeV darkish matter and electrons, the researchers used an strategy that relates the darkish matter interplay price to the gadget’s dielectric properties. Specifically, when power is deposited by darkish matter, electrons within the materials needs to be rearranged in a specific approach, affecting the wire’s electromagnetic subject. The staff’s calculations present higher bounds on electron scattering and absorption charges with sub-MeV and sub-eV particles. The researchers say that these constraints enhance on earlier limits by a number of orders of magnitude.
Rachel Berkowitz is a Corresponding Editor for Physics Magazine primarily based in Vancouver, Canada.
- Y. Hochberg et al., “New constraints on dark matter from superconducting nanowires,” Phys. Rev. D 106, 112005 (2022).