Researchers make new discovery about neutrinos, bringing us one step closer to perhaps solving one of the biggest myster

Jul 19, 2013
Distribution of reconstructed energy of electron-neutrino candidates in Super Kamiokande: the black points represent the data, the pink histogram represents the expected energy distribution of electron-neutrino candidates that have oscillated from muon neutrinos, and the green histogram represents the expected energy distribution of non-oscillated electron neutrinos.

International research including the UK and Japan has confirmed that subatomic particles called neutrinos have a new form of identity-shifting property. Announced today (19 July 2013) these results could one day help scientists explain why the universe contains matter but very little antimatter.

The findings are further confirmation from the T2K in Japan of changing between different types, or oscillating, in a new way.

Dr Alfons Weber, Professor of Physics at STFC and the University of Oxford is one of many scientists in the UK working on T2K - he designed the electronics for the experiment. He explains: "The UK particle physics community was one of the driving forces behind this experiment. We not only provided part of the detector that characterises the beam, but also designed the target that produces the neutrinos in the first place. The long years of hard work have now come to fruition.

"Our findings now open the possibility to study this process for neutrinos and their partners, the anti-neutrinos. A difference in the rate of electron or anti-electron neutrino being produced may lead us to understand why there is so much more matter than antimatter in the universe. The neutrino may be the very reason we are here."

In 2011, the T2K collaboration announced the first indication of this process. Now with 3.5 times more data and a significance of 7.5 , this behaviour is firmly established and can now be called a discovery.

There are three types, or 'flavours,' of neutrinos – one paired with the electron (called the electron neutrino), and two more paired with the electron's heavier cousins, the muon and tau leptons. These different flavours of neutrinos can spontaneously change into each other, a phenomenon called neutrino oscillations. Observations have previously been made of a number of different types of oscillations, however the T2K results are the first discovery of the appearance of electron neutrinos in a beam of muon neutrinos, and it is this kind of oscillation which is the key to making measurements to distinguish the oscillations of neutrinos and anti-neutrinos.

To explore the neutrinos' oscillations, the T2K experiment fired a beam of neutrinos from the J-PARC laboratory at Tokai Village on the eastern coast of Japan, and detected them at the Super-Kamiokande neutrino detector, 295 km away in the mountains of the north-western part of the country. Here, the scientists looked to see if the neutrinos at the end of the beam matched those emitted at the start.

They found 22.5 neutrinos appearing in the beam of neutrinos, where if there were no oscillations they only expected to see an average of 6.4. This indicates the discovery of the new type of oscillation. Now the team must make more accurate measurements of this new oscillation, and then run their experiment with an anti-neutrino beam to see if the results change.

Professor Dave Wark of the Science and Technology Facilities Council (STFC) and Oxford University, leads the UK's involvement in the international experiment. He said: "It's a joy to see T2K deliver the science we designed it for. I have been working on this for more than a decade, and what these results tell us is that we have more than another decade of work ahead of us.

"We have seen a new way for neutrinos to change, and now we have to find out if neutrinos and anti-neutrinos do it the same way. If they don't, it may be a clue to help solve the mystery of where the matter in the universe came from in the first place. Surely answering that is worth a couple of decades of work!"

STFC is the UK sponsor of particle physics and supports the UK universities involved in the T2K experiment.

Explore further: Superconducting circuits, simplified

Related Stories

Neutrinos change flavors while crossing Japan

Jun 15, 2011

By shooting a beam of neutrinos through a small slice of the Earth under Japan, physicists say they've caught the particles changing their stripes in new ways. These observations may one day help explain why the universe ...

Rare find backs shape-shifting neutrino

Mar 27, 2013

Physicists announced further proof Wednesday for a theory that mysterious particles called neutrinos which go "missing" on the journey from the Sun to Earth are in fact shape-shifting along the way, arriving ...

EUROnu project recommends building Neutrino Factory

Jun 19, 2013

(Phys.org) —The European Union's Seventh Framework Programme, EUROnu, has submitted its findings to a panel at CERN. Charged with choosing a project to study the nature of matter and antimatter, the project ...

New results confirm standard neutrino theory

Feb 16, 2010

(PhysOrg.com) -- In its search for a better understanding of the mysterious neutrinos, a group of experimenters at DOE’s Fermi National Accelerator Laboratory has announced results that confirm the theory ...

Fermilab experiment weighs in on neutrino mystery

Jun 24, 2011

Scientists of the MINOS experiment at the Department of Energy's Fermi National Accelerator Laboratory announced today (June 24) the results from a search for a rare phenomenon, the transformation of muon ...

Recommended for you

Superconducting circuits, simplified

Oct 17, 2014

Computer chips with superconducting circuits—circuits with zero electrical resistance—would be 50 to 100 times as energy-efficient as today's chips, an attractive trait given the increasing power consumption ...

Protons hog the momentum in neutron-rich nuclei

Oct 16, 2014

Like dancers swirling on the dance floor with bystanders looking on, protons and neutrons that have briefly paired up in the nucleus have higher-average momentum, leaving less for non-paired nucleons. Using ...

Cosmic jets of young stars formed by magnetic fields

Oct 16, 2014

Astrophysical jets are counted among our Universe's most spectacular phenomena: From the centers of black holes, quasars, or protostars, these rays of matter sometimes protrude several light years into space. ...

User comments : 7

Adjust slider to filter visible comments by rank

Display comments: newest first

shavera
5 / 5 (9) Jul 19, 2013
For those keeping score at home, this is a conclusive (7.5 sigma) muon-generated neutrino to electron-type neutrino oscillation. A cursory check doesn't seem to be turning up more precise measures of mixing angles or anything.
ValeriaT
Jul 19, 2013
This comment has been removed by a moderator.
Torbjorn_Larsson_OM
4.5 / 5 (14) Jul 19, 2013
How is it that cracktards have to piss on every actual science news with their not-science?

@shavera: Thanks for the info!
dirk_bruere
not rated yet Jul 19, 2013
Does frequency of oscillation have any meaning?
Aliensarethere
1 / 5 (2) Jul 20, 2013
It would be great if physorg could link to an article that explains why a difference between oscillating neutrinoes, might tell us why there are more matter than anti-matter in the Universe.
EyeNStein
1 / 5 (3) Jul 20, 2013
This has really only established the baseline of neutrino oscillations - no new physics yet. It has only confirmed what the maths predicted 50 years ago.
Very likely their follow on experiment will only show that the results are the same with the opposite weak iso-spin particles (anti-neutrinos), as the masses of the 3 anti-neutrinos are thought to be the same as the electron/muon/tau neutrinos.
However it could be interesting if they oscillate differently when anti-neutrinos pass through normal matter if the weak MSW effect were not symmetric.
See Wiki for details:-
http://en.wikiped...illation
EyeNStein
1 / 5 (3) Jul 20, 2013
Does frequency of oscillation have any meaning?


The frequency of the oscillation is indicative of the kinetic energy the neutrino was ejected/created with in whatever 'weak' interaction/decay created it. As the three quantum superimposed neutrino flavours drift apart in flight as there masses are different.
EyeNStein
1 / 5 (3) Jul 20, 2013
Does frequency of oscillation have any meaning?


The frequency of the oscillation is indicative of the kinetic energy the neutrino was ejected/created with in whatever 'weak' interaction/decay created it. As the three quantum superimposed neutrino flavours drift apart in flight as their masses are different.