Physicists Don't Know the Mass of a Neutrino, But Now They Know it's No Larger Than 1 Electron Volt - Universe Today - Canadanewsmedia
Connect with us

Science

Physicists Don't Know the Mass of a Neutrino, But Now They Know it's No Larger Than 1 Electron Volt – Universe Today

Published

on


The Standard Model of Particle Physics is one of science’s most impressive feats. It’s a rigorous, precise effort to understand and describe three of the four fundamental forces of the Universe: the electromagnetic force, the strong nuclear force, and the weak nuclear force. Gravity is absent because so far, fitting it into the Standard Model has been extremely challenging.

But there are some holes in the Standard Model, and one of them involves the mass of the neutrino.

The existence of the neutrino was first proposed in 1930, then detected in 1956. Since then, physicists have learned there are three types of neutrinos, and they’re abundant and elusive. Only special facilities can detect them because they rarely interact with other matter. There are several sources for them, and some of them have been zipping through space since the Big Bang, but most of the neutrinos near Earth come from the Sun.

The Standard Model predicts that neutrinos have no mass, like photons. But physicists have found that the three types of neutrinos can transform into one another as they move. According to physicists, they should only be able to do that if they do have mass.

The Standard Model of Elementary Particles. Image: By MissMJ – Own work by uploader, PBS NOVA [1], Fermilab, Office of Science, United States Department of Energy, Particle Data Group, CC BY 3.0

But how much mass? That’s a question that’s been dogging particle physicists. And answering that question is part of what drives scientists at KATRIN (Karlsruhe Tritium Neutrino Experiment.)

The 10 meter high-resolution spectrometer at the heart of KATRIN (Karlsruhe Tritium Neutrino Experiment. Image Credit: KATRIN Collaboration.
The 10 meter high-resolution spectrometer at the heart of KATRIN (Karlsruhe Tritium Neutrino Experiment. Image Credit: KATRIN Collaboration.

“These findings by the KATRIN collaboration reduce the previous mass range for the neutrino by a factor of two…”

HAMISH ROBERTSON, KATRIN SCIENTIST AND PROFESSOR EMERITUS OF PHYSICS AT THE UNIVERSITY OF WASHINGTON.

A team of researchers have come up with part of an answer to that: the mass of the neutrino can be no larger than 1.1 electron volts (eV.) This is a reduction of the upper limit of a neutrino’s mass by nearly 1 eV; from 2 eV down to 1.1 eV. By building on previous experiments that set the lower mass limit at 0.02 eV, these researchers have set a new range for the neutrino’s mass. It shows that a neutrino has less than 1/500,000th the mass of an electron. This is an important step in the advancement of the Standard Model.

“Knowing the mass of the neutrino will allow scientists to answer fundamental questions in cosmology, astrophysics and particle physics…”

Hamish Robertson, KATRIN scientist and professor emeritus of physics at the University of Washington.

The researchers behind this work come from 20 different research institutions around the world. They’re working with KATRIN at the Karlsruhe Institute of Technology in Germany. The KATRIN facility features a 10 meter high-resolution spectrometer which allows it to measure electron energies with great precision.

The KATRIN instrument features a high-resolution spectrometer that allows it to measure electron volts with extreme precision. This diagram shows the layout and major features of the KATRIN experimental facility at the Karlsruhe Institute of Technology. Image Credit:  Karlsruhe Institute of Technology
The KATRIN instrument features a high-resolution spectrometer that allows it to measure electron volts with extreme precision. This diagram shows the layout and major features of the KATRIN experimental facility at the Karlsruhe Institute of Technology. Image Credit: Karlsruhe Institute of Technology

The KATRIN team presented their results at the 2019 Topics in Astroparticle and Underground Physics conference in Toyama, Japan, on September 13th.

“Knowing the mass of the neutrino will allow scientists to answer fundamental questions in cosmology, astrophysics and particle physics, such as how the universe evolved or what physics exists beyond the Standard Model,” said Hamish Robertson, a KATRIN scientist and professor emeritus of physics at the University of Washington. “These findings by the KATRIN collaboration reduce the previous mass range for the neutrino by a factor of two, place more stringent criteria on what the neutrino’s mass actually is, and provide a path forward to measure its value definitively.”

Neutrinos are notoriously difficult to detect, even though they’re abundant. Only photons are more abundant. Like their name says, they’re electrically neutral. This makes detecting them extremely difficult. There are neutrino observatories sunk deep in the Antarctic ice, and also deep in abandoned mines. They often use heavy water to entice the neutrinos to interact. When a neutrino does interact, it produces Cherenkov radiation that can be measured.

Neutrinos are nearly impossible to detect. One neutrino observatory, called the IceCube Neutrino Laboratory, tries to detect them by sinking detectors deep into the cold, antarctic ice, where it tries to catch the rare times when neutrinos interact with other matter. This image shows a visual representation of one of the highest-energy neutrino detections superimposed on a view of the IceCube Lab at the South Pole. Credit: IceCube Collaboration.
Neutrinos are nearly impossible to detect. One neutrino observatory, called the IceCube Neutrino Laboratory, ) tries to detect them by sinking strings of detectors deep into the cold, dark, Antarctic ice, where it tries to observe the rare times when neutrinos interact with other matter. This image shows a visual representation of one of the highest-energy neutrino detections superimposed on a view of the IceCube Lab at the South Pole. Credit: IceCube Collaboration.

“If you filled the solar system with lead out to fifty times beyond the orbit of Pluto, about half of the neutrinos emitted by the sun would still leave the solar system without interacting with that lead,” said Robertson.

The history of the neutrino has evolved over time with experiments such as KATRIN. Originally, the Standard Model predicted neutrinos would have no mass. But in 2001, two different detectors showed their mass is non-zero. The 2015 Nobel Prize in Physics was awarded to two scientists who showed that neutrinos can oscillate between types, showing they have mass.

The KATRIN facility measures the mass of neutrinos indirectly. It works by monitoring the decay of tritium, which is a highly-radioactive form of hydrogen. As the tritium isotope decays, it emits pairs of particles: an electron and an anti-neutrino. Together, they share 18,560 eV of energy.

The tell-tale blue glow of Cherenkov radiation from the Advanced Test Reactor in Idaho. Image Credit: By Argonne National Laboratory - originally posted to Flickr as Advanced Test Reactor core, Idaho National LaboratoryUploaded using F2ComButton, CC BY-SA 2.0, https://commons.wikimedia.org/w/index.php?curid=27024528
The tell-tale blue glow of Cherenkov radiation from the Advanced Test Reactor in Idaho. Image Credit: By Argonne National Laboratory – originally posted to Flickr as Advanced Test Reactor core, Idaho National LaboratoryUploaded using F2ComButton, CC BY-SA 2.0, https://commons.wikimedia.org/w/index.php?curid=27024528

In most cases, the pair of particles share the 18,560 eV equally. But in rare instances, the electron hogs most of the energy, leaving the neutrino with very little. These rare instances are what scientists are focused on.

Due to E=mC2, the tiny amount of energy left for the neutrino in these rare cases must also equal its mass. Because KATRIN has the power to measure the electron accurately, it’s also able to determine the neutrino’s mass.

“Solving the mass of the neutrino would lead us into a brave new world of creating a new Standard Model,” said Peter Doe, a research professor of physics from the University of Washington who works on KATRIN.

This new Standard Model that Doe mentions may have the potential to account for dark matter, which makes up most of the matter in the Universe. Efforts like KATRIN may one day detect another, fourth type of neutrino called the sterile neutrino. So far this fourth type is only conjecture, but it is a candidate for dark matter.

A computer simulation of the distribution of matter in the Universe. Orange regions host galaxies; blue structures are gas and dark matter. It’s possible that there’s a fourth type of undiscovered neutrino called a sterile neutrino that could conceivably account for all dark matter in the Universe. Credit: TNG Collaboration

“Neutrinos are strange little particles,” said Doe. “They’re so ubiquitous, and there’s so much we can learn once we determine this value.”

Showing that neutrinos have mass, and constraining the range of that mass, are both important. But particle physicists still don’t know how they gain their mass. It’s probably different than how other particles gain theirs.

Results like this from KATRIN are helping close a hole in the Standard Model, and in our overall understanding of the Universe. The Universe is full of ancient neutrinos from the Big Bang, and every advancement in the mass of the neutrino helps us understand how the Universe formed and evolved.

More:

Let’s block ads! (Why?)



Source link

Continue Reading

Science

Billionaire Bezos unveils plans to land humans on Moon, with a little help from some old friends – The Register

Published

on

By


Blue Origin and industry vets eye a slice of NASA’s lunar lander largesse

Richest person in the world, Jeff Bezos, yesterday pitched NASA a team mostly made up of the usual suspects to build a lunar lander for the agency’s ambitious 2024 boots-on-Moon goal.

Speaking at the International Astronautical Congress in Washington, Bezos announced the “national team”, of which his Blue Origin would be the prime contractor (naturally). The members consist of Lockheed Martin for the Ascent Stage, Northrop Grumman for the Transfer Element and Draper providing the guidance and navigation systems.

“We could not ask for better partners,” intoned the billionaire, which is fair enough. After all, elements of all the companies in the team-up worked on the Apollo program back in the day (although those engineers will have long been put out to pasture.)

The Transfer Element will guide the stack from lunar orbit to close to the Moon, from whence the Descent Element will conduct a powered descent. Lockheed Martin’s ascent module will then send the freshly minted Moonwalkers back into space.

Blue Origin will also be building the descent element of the lander, which uses the company’s BE-7 engine. The powerplant, Bezos said, is fuelled by liquid hydrogen and oxygen and as well being “highly throttleable” and developing 10,000 pounds of thrust.

The BE-7, of course, has yet to actually leave the test stand. Bezos told the audience that to date, the company had managed 13 minutes of test time, including a three-minute continuous firing.

That same engine, Bezos added, would be used by Northrop Grumman in the transfer element of the lunar lander stack.

Bezos unveiled the Blue Moon lander back in May and the announcement of the National Team is an indicator that it will take more than one company to meet the 2024 goal. It will also reassure those within NASA nervous about flinging cash at a company that has yet to even make Earth orbit, let alone do anything in deep space.

And NASA has lots of experience in giving money to Lockheed Martin and Northrop Grumman after all.

Grumman, of course, built the original Apollo Lunar Module back in NASA’s glory days while Draper provided the guidance systems for the Moon missions.

These days, Northrop Grumman provides NASA with ISS cargo services and is working on both the boosters for the eternally-delayed Space Launch System and the habitat for the agency’s Lunar Gateway.

Draper has continued to work on precision guidance, although there is a delightful hole to tumble down in researching the Apollo guidance units, particularly efforts to fire up the old things once more. Naturally, the hand-woven circuitry of the Apollo era won’t feature this time around.

NASA is due to select two contractor teams in late 2020 to actually build the lander, having asked for proposals (and deleted certain reusability requirements in the rush to 2024). ®

Sponsored:
Delivering on the multi-cloud dream: Clear strategies for success

Let’s block ads! (Why?)



Source link

Continue Reading

Science

Bezos's Blue Origin partners with Lockheed, others on moon lander – Financial Post

Published

on

By


WASHINGTON — U.S. billionaire Jeff Bezos said on Tuesday his space company Blue Origin has signed agreements with Lockheed Martin Corp, Northrop Grumman Corp and research and development organization Draper for development of its lunar lander designed to help NASA put humans on the moon by 2024.

Blue Origin’s so-called Blue Moon lunar lander, unveiled by Bezos in May, is in development and sits at the center of the space company’s ambition to ferry humans into deep space and land key contracts from the U.S. space agency for space exploration.

“I’m excited to announce that we put together a national team to go back to the moon,” Bezos, founder and CEO of online retail giant Amazon, said at the International Astronautical Congress.

The four companies, with Blue Origin as the lead contractor, plan to submit a proposal for the lander to NASA under its Artemis lunar program, an accelerated mission to the moon kickstarted in March by U.S. Vice President Mike Pence.

Bezos called the partnerships a “national team” whose history in space exploration fits the Blue Moon’s mission. Lockheed is separately developing the moon-bound astronaut capsule named Orion. Northrop helped NASA build the Apollo lunar landers in the 1960s. Draper, a not-for-profit research and development organization, built NASA’s navigation computers for Apollo lunar landers. (Reporting by Joey Roulette; Editing by Sandra Maler)

Let’s block ads! (Why?)



Source link

Continue Reading

Science

A giant full beaver moon set to dazzle Metro Vancouver skies – Vancouver Courier

Published

on

By


While it is getting darker earlier in Metro Vancouver, this month’s full beaver moon promises to illuminate the night sky.

The November full moon is thought to have derived its funny name because it occurred during the optimal time to trap the furry creatures. In fact, both colonial Americans as well as the Algonquin tribes referred to it as such.

article continues below

“Why this name? Back then, this was the month to set beaver traps before the swamps froze, to ensure a supply of warm winter furs,” reports Farmer’s Almanac.

While it is commonly known as the beaver moon, it was also called the Full Frost Moon by other North American Tribes.

According to the Old Farmer’s Almanac, the moon will be fullest during the day on Tuesday, Nov. 12. However, Vancouver stargazers will still be able to see the nearly-full moon in all her celestial glory the night before (Nov. 11) as well as later that night (Nov. 12).

What’s more, this full moon casts long, hauntingly beautiful shadows in the Northern Hemisphere. They are similar to those cast by the midday summer sun, as the moon is extremely high in the sky during this time.

Stargazers should opt to travel as far away from city lights as possible in order to avoid light pollution that will obscure the clarity of heavenly bodies. While this works best the in more remote places, anywhere that has a higher elevation will also provide more ideal viewing conditions.

Click here for original article.

Let’s block ads! (Why?)



Source link

Continue Reading

Trending