Researchers at the National Institute of Standards and Technology (NIST), the Massachusetts Institute of Technology (MIT), and the Perimeter Institute recently established new constraints on dark photons, which are hypothetical particles and well-established dark matter candidates. Their findings, presented in an article published in Physical Verification Letterswere achieved with a new superconducting nanowire single photon detector (SNSPD) they developed.
“There is close collaboration between our research groups at NIST and MIT, led by Dr. Sae Woo Nam and Prof. Karl Berggren, respectively,” Jeff Chiles, one of the researchers who conducted the study, told Phys.org. “We are working together to advance technology and applications for ultra-sensitive devices called superconducting nanowire single-photon detectors, or SNSPDs.”
In recent years, Chiles and his colleagues have been considering potential applications that would benefit from the SNSPD detectors they have been working on, which have virtually no background noise, among other beneficial properties. They were eventually presented to a group of theoretical physicists from the Perimeter Institute for Theoretical Physics in Canada.
This team of theorists had an interesting idea for a dark matter detector that could operate in a completely different domain than those currently used to search for dark matter. This detector, a multilayer dielectric optical haloscope, was a promising concept, but it would require an optical detector far more powerful than those on the market today.
“This turned out to be a perfect match, as the MIT and NIST groups were able to build and test the detector and apparatus,” explained Chiles. “So we got together and called our project LAMPOST (Light A’ Multilayer Periodic Optical SNSPD Target). Our goal was to achieve the first experimental proof-of-concept for this idea and to prove that it can be used to search for dark matter with better sensitivity than the already established limits.”
The optical detector developed by Chiles and his colleagues is based on a structure known as a dielectric stack or target. This structure can generate signal photons of interest by converting a non-relativistic dark photon into a relativistic photon with the same frequency.
“First, we performed an analysis of the setup of the apparatus, optical simulations to determine the optical collection efficiency, a simulation of the detection efficiency, a calculation of the influence of polarization on the dark matter signal and the minimum signal power consistent with the possible series of target properties,” Ilya Charaev, another researcher involved in the study, told Phys.org. “Using the SNSPD technique, all incoming signals were registered over 180 hours of exposure.”
To limit dark matter coupling, the researchers estimated the dark count rate, also known as “noise,” for the SNSPD detector they developed. Interestingly, their estimated noise value is the lowest among all values reported in the physics literature.
“Remarkably, we achieved our goal because we were able to scan for one type of dark matter, specifically ‘dark photons’, twice as sensitively as anything else in the energy range we were looking for,” said Chiles. “By and large, this is still a small notch out of a huge range of dark matter possibilities. But for our first run, pushing existing boundaries is an important first step, and to me it speaks to the power and simplicity of the multilayer dielectric optical haloscope approach.”
In their experiments, this team of researchers gathered valuable insights that could inform future searches for dark photons and potentially also fuel the use of SNSPDs. Chiles and his colleagues have not only set new constraints on dark photons, but also learned more about their detector’s capabilities.
Most importantly, they found that the noise in their detector was incredibly low. More specifically, the team observed just 5 “false events” for one of their single photon detectors over 180 hours of data collection, suggesting their technology is very sensitive to weak signals.
“It’s exciting to imagine what other physics experiments involving rare events this technology could be applied to in the near future,” added Chiles. “In the meantime, we plan to scale up the experiment from here. The first pass was a proof-of-concept, but the next one will be sensitive enough to cover a large dark matter parameter space that will include both axions and dark photons.”
Gravitational wave detectors to search for dark matter
Jeff Chiles et al, New Constraints on Dark Photon-Dark Matter Using Superconducting Nanowire Detectors in an Optical Haloscope, Physical Verification Letters (2022). DOI: 10.1103/PhysRevLett.128.231802
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Citation: Study places new constraints on dark photons using a new dielectric optical haloscope (2022 July 6) retrieved July 8, 2022 from https://phys.org/news/2022-07-constraints-dark-photons- dielectric-optical.html
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