From DOE’s Lawrence Livermore National Laboratory (US) : “Sterile neutrinos may be portal to the dark side”

From DOE’s Lawrence Livermore National Laboratory (US)

4.27.21 [Just now in social media.]

Anne M Stark
stark8@llnl.gov
925-422-9799

1
Schematic of the “BeEST” experiment. Radioactive beryllium-7 is implanted into the superconducting sensor. Precision measurements of the decay products could indicate the presence of hypothesized “sterile neutrinos”.

“Sterile neutrinos” are theoretically predicted new particles that offer an intriguing possibility in the quest for understanding the Dark Matter in our universe.

Unlike the known “active” neutrinos in the Standard Model (SM) of Particle Physics, these sterile neutrinos do not interact with normal matter as they move through space, making them very difficult to detect.

A team of interdisciplinary researchers, led by Lawrence Livermore National Laboratory (LLNL) and the Colorado School of Mines (US), has demonstrated the power of using nuclear decay in high-rate quantum sensors in the search for sterile neutrinos. The findings are the first measurements of their kind.

The research has been featured recently as a DOE Office of Science Highlight and will jump-start an extended project to look for one of the most promising candidates for dark matter, the strange unidentified material that permeates the universe and accounts for 85 percent of its total mass.

The experiment involves implanting radioactive beryllium-7 atoms into superconducting sensors developed at LLNL and has been nicknamed the “BeEST” for “Beryllium Electron-capture with Superconducting Tunnel junctions.” When the beryllium-7 decays by electron capture into lithium-7 and a neutrino, the neutrino escapes from the sensor, but the recoil energy of the lithium-7 provides a measure of the neutrino mass. If a heavy sterile neutrino with mass mc^2 were to be generated in a faction of the decays, the lithium-7 recoil energy would be reduced and produce a measurable signal, even though the elusive neutrino itself is not detected directly.

With a measurement time of just 28 days using a single sensor, the data excludes the existence of sterile neutrinos in the mass range of 100 to 850 kiloelectronvolts down to a 0.01 percent level of mixing with the active neutrinos — better than all previous decay experiments in this range. In addition, simulations on LLNL supercomputers have helped the team understand some of the materials effects in the detector that need to be accounted for to gain confidence in potential sterile neutrino detection events.

“This research effort lays the groundwork for even more powerful searches for these new particles using large arrays of sensors with new superconducting materials,” said LLNL scientist Stephan Friedrich, lead author of the research appearing in Physical Review Letters.

The Standard Model of Particle Physics is one of the crowning achievements in modern science and the cornerstone of current subatomic studies. Despite its success, the SM is known to be incomplete, and physics beyond the Standard Model (BSM) is required to develop a full description of the universe. The neutrino sector offers an intriguing avenue for BSM physics as the observation of nonzero neutrino masses currently provides the only confirmed violation of the SM as it was originally constructed.

“Sterile neutrinos are exciting because they are strong candidates for so-called ‘warm’ dark matter, and they also may help to address the origin of the matter-antimatter asymmetry of the universe,” Friedrich said.

Other LLNL authors include Geonbo Kim, Vincenzo Lordi and Amit Samanta.

This research is funded by the Laboratory Directed Research and Development program.

_____________________________________________________________________________________

Dark Matter Background
Fritz Zwicky discovered Dark Matter in the 1930s when observing the movement of the Coma Cluster., Vera Rubin a Woman in STEM denied the Nobel, some 30 years later, did most of the work on Dark Matter.

Fritz Zwicky from http:// palomarskies.blogspot.com.


Coma cluster via NASA/ESA Hubble.


In modern times, it was astronomer Fritz Zwicky, in the 1930s, who made the first observations of what we now call dark matter. His 1933 observations of the Coma Cluster of galaxies seemed to indicated it has a mass 500 times more than that previously calculated by Edwin Hubble. Furthermore, this extra mass seemed to be completely invisible. Although Zwicky’s observations were initially met with much skepticism, they were later confirmed by other groups of astronomers.
Thirty years later, astronomer Vera Rubin provided a huge piece of evidence for the existence of dark matter. She discovered that the centers of galaxies rotate at the same speed as their extremities, whereas, of course, they should rotate faster. Think of a vinyl LP on a record deck: its center rotates faster than its edge. That’s what logic dictates we should see in galaxies too. But we do not. The only way to explain this is if the whole galaxy is only the center of some much larger structure, as if it is only the label on the LP so to speak, causing the galaxy to have a consistent rotation speed from center to edge.
Vera Rubin, following Zwicky, postulated that the missing structure in galaxies is dark matter. Her ideas were met with much resistance from the astronomical community, but her observations have been confirmed and are seen today as pivotal proof of the existence of dark matter.

Astronomer Vera Rubin at the Lowell Observatory in 1965, worked on Dark Matter (The Carnegie Institution for Science).


Vera Rubin measuring spectra, worked on Dark Matter (Emilio Segre Visual Archives AIP SPL).


Vera Rubin, with Department of Terrestrial Magnetism (DTM) image tube spectrograph attached to the Kitt Peak 84-inch telescope, 1970. https://home.dtm.ciw.edu.


_____________________________________________________________________________________

Dark Matter Research

See the full article here .


five-ways-keep-your-child-safe-school-shootings

Please help promote STEM in your local schools.

Stem Education Coalition

Operated by Lawrence Livermore National Security, LLC, for the Department of Energy’s National Nuclear Security Administration

DOE’s Lawrence Livermore National Laboratory (LLNL) (US) is an American federal research facility in Livermore, California, United States, founded by the University of California-Berkeley (US) in 1952. A Federally Funded Research and Development Center (FFRDC), it is primarily funded by the U.S. Department of Energy (DOE) and managed and operated by Lawrence Livermore National Security, LLC (LLNS), a partnership of the University of California, Bechtel, BWX Technologies, AECOM, and Battelle Memorial Institute in affiliation with the Texas A&M University System (US). In 2012, the laboratory had the synthetic chemical element livermorium named after it.
LLNL is self-described as “a premier research and development institution for science and technology applied to national security.” Its principal responsibility is ensuring the safety, security and reliability of the nation’s nuclear weapons through the application of advanced science, engineering and technology. The Laboratory also applies its special expertise and multidisciplinary capabilities to preventing the proliferation and use of weapons of mass destruction, bolstering homeland security and solving other nationally important problems, including energy and environmental security, basic science and economic competitiveness.

The Laboratory is located on a one-square-mile (2.6 km^2) site at the eastern edge of Livermore. It also operates a 7,000 acres (28 km2) remote experimental test site, called Site 300, situated about 15 miles (24 km) southeast of the main lab site. LLNL has an annual budget of about $1.5 billion and a staff of roughly 5,800 employees.

LLNL was established in 1952 as the University of California Radiation Laboratory at Livermore, an offshoot of the existing UC Radiation Laboratory at Berkeley. It was intended to spur innovation and provide competition to the nuclear weapon design laboratory at Los Alamos in New Mexico, home of the Manhattan Project that developed the first atomic weapons. Edward Teller and Ernest Lawrence, director of the Radiation Laboratory at Berkeley, are regarded as the co-founders of the Livermore facility.

The new laboratory was sited at a former naval air station of World War II. It was already home to several UC Radiation Laboratory projects that were too large for its location in the Berkeley Hills above the UC campus, including one of the first experiments in the magnetic approach to confined thermonuclear reactions (i.e. fusion). About half an hour southeast of Berkeley, the Livermore site provided much greater security for classified projects than an urban university campus.

Lawrence tapped 32-year-old Herbert York, a former graduate student of his, to run Livermore. Under York, the Lab had four main programs: Project Sherwood (the magnetic-fusion program), Project Whitney (the weapons-design program), diagnostic weapon experiments (both for the DOE’s Los Alamos National Laboratory(US) and Livermore laboratories), and a basic physics program. York and the new lab embraced the Lawrence “big science” approach, tackling challenging projects with physicists, chemists, engineers, and computational scientists working together in multidisciplinary teams. Lawrence died in August 1958 and shortly after, the university’s board of regents named both laboratories for him, as the Lawrence Radiation Laboratory.

Historically, the DOE’s Lawrence Berkeley National Laboratory (US) and Livermore laboratories have had very close relationships on research projects, business operations, and staff. The Livermore Lab was established initially as a branch of the Berkeley laboratory. The Livermore lab was not officially severed administratively from the Berkeley lab until 1971. To this day, in official planning documents and records, Lawrence Berkeley National Laboratory is designated as Site 100, Lawrence Livermore National Lab as Site 200, and LLNL’s remote test location as Site 300.

The laboratory was renamed Lawrence Livermore Laboratory (LLL) in 1971. On October 1, 2007 LLNS assumed management of LLNL from the University of California, which had exclusively managed and operated the Laboratory since its inception 55 years before. The laboratory was honored in 2012 by having the synthetic chemical element livermorium named after it. The LLNS takeover of the laboratory has been controversial. In May 2013, an Alameda County jury awarded over $2.7 million to five former laboratory employees who were among 430 employees LLNS laid off during 2008.The jury found that LLNS breached a contractual obligation to terminate the employees only for “reasonable cause.” The five plaintiffs also have pending age discrimination claims against LLNS, which will be heard by a different jury in a separate trial.[6] There are 125 co-plaintiffs awaiting trial on similar claims against LLNS. The May 2008 layoff was the first layoff at the laboratory in nearly 40 years.

On March 14, 2011, the City of Livermore officially expanded the city’s boundaries to annex LLNL and move it within the city limits. The unanimous vote by the Livermore city council expanded Livermore’s southeastern boundaries to cover 15 land parcels covering 1,057 acres (4.28 km^2) that comprise the LLNL site. The site was formerly an unincorporated area of Alameda County. The LLNL campus continues to be owned by the federal government.

LLNL/NIF

DOE Seal

NNSA