Forum for Science, Industry and Business

Sponsored by:     3M 
Search our Site:

 

Chameleon particles from the Sun

22.04.2002


The Sun emits electron-neutrinos, elementary particles of matter that have no electric charge and very little mass, created in vast numbers by the thermonuclear reactions that fuel our parent star. Since the early 1970s, several experiments have detected neutrinos arriving on Earth, but they have found only a fraction of the number expected from detailed theories of energy production in the Sun. This meant there was either something wrong with our theories of the Sun, or our understanding of neutrinos. It turns out that our theories of how the Sun is powered look like being correct according to a team of scientists from the UK, the US and Canada whose latest results from research into solar neutrinos were announced on Saturday [20 April 2002]. What`s more, these ghostly particles have `chameleon` type capabilities, changing from one type of neutrino into another on their journey from the Sun to Earth.



The scientists used data taken entirely from the Sudbury Neutrino Observatory [SNO] in Canada which shows without doubt that the number of observed solar neutrinos is only a fraction of the total emitted from the Sun - clear evidence that they have chameleon type properties and change type en-route to Earth.

Says Project Director Art McDonald of Queen`s University, Canada, "These new results show in a clear, simple and accurate way that solar neutrinos change their type. The total number of neutrinos we observe is in excellent agreement with calculations of the nuclear reactions powering the Sun. The SNO team is really excited because these measurements enable neutrino properties to be defined with much greater certainty in fundamental theories of elementary particles."


Neutrinos are known to exist in three types related to three different charged particles - the electron, and its lesser known relatives the muon and the tau. The Sun emits electron neutrinos, which are created in the thermonuclear reactions in the solar core. Previous experiments have found fewer electron neutrinos than suggested by calculations based on how the Sun burns - the famous "solar neutrino problem".


The results announced on Saturday at the Joint American Physical Society/American Astronomical Society meetings in Albuquerque, New Mexico, show that the number of electron-neutrinos detected is about 1/3 of the number expected according to calculations based on the latest sophisticated models of the solar core. The SNO detector uses the unique properties of heavy water - where the hydrogen has an extra neutron in its nucleus - to detect not only electron neutrinos through one type of reaction, but also all three known neutrino types through a different reaction. The total number of all three types of neutrino agrees well with the calculations. This shows unambiguously that electron neutrinos emitted by the Sun have changed to muon or tau neutrinos before they reach Earth.

Dr. Andre Hamer, of Los Alamos National Laboratory, said, "In order to make these measurements we had to restrict the radioactivity in the detector to minute levels and determine both neutrino signals and the detector background very accurately - to show clearly that we are observing neutrinos from the Sun. The care taken throughout this experiment to minimise radioactivity, and the careful calibration and analysis of our data, has enabled us to make these neutrino measurements with great accuracy"

In June last year results from the detection of electron neutrinos at SNO first indicated, with a certainty of 99.9%, that neutrinos change type on their way from the Sun, thus solving the long-standing problem - or so it was thought. However, these conclusions were based on comparisons of the SNO results with those from a different experiment, the Super-Kamiokande detector, located in Japan.

Prof. Dave Wark of the University of Sussex and the Rutherford Appleton Laboratory, Oxford, commented, " Whenever a scientific conclusion relies on two experiments, and on the theory connecting them, it is twice as hard to be certain that you understand what is going on. We are therefore much more certain now that we have really shown that solar neutrinos change type".

The latest results, entirely from the SNO detector, (and which have been submitted to Physical Review Letters) are 99.999% accurate, and are of great importance because of the way in which physicists think that the neutrinos - long thought to be massless particles - change types only happens if the different types have different masses.

Gill Ormrod | alphagalileo

More articles from Physics and Astronomy:

nachricht First Juno science results supported by University of Leicester's Jupiter 'forecast'
26.05.2017 | University of Leicester

nachricht Measured for the first time: Direction of light waves changed by quantum effect
24.05.2017 | Vienna University of Technology

All articles from Physics and Astronomy >>>

The most recent press releases about innovation >>>

Die letzten 5 Focus-News des innovations-reports im Überblick:

Im Focus: Can the immune system be boosted against Staphylococcus aureus by delivery of messenger RNA?

Staphylococcus aureus is a feared pathogen (MRSA, multi-resistant S. aureus) due to frequent resistances against many antibiotics, especially in hospital infections. Researchers at the Paul-Ehrlich-Institut have identified immunological processes that prevent a successful immune response directed against the pathogenic agent. The delivery of bacterial proteins with RNA adjuvant or messenger RNA (mRNA) into immune cells allows the re-direction of the immune response towards an active defense against S. aureus. This could be of significant importance for the development of an effective vaccine. PLOS Pathogens has published these research results online on 25 May 2017.

Staphylococcus aureus (S. aureus) is a bacterium that colonizes by far more than half of the skin and the mucosa of adults, usually without causing infections....

Im Focus: A quantum walk of photons

Physicists from the University of Würzburg are capable of generating identical looking single light particles at the push of a button. Two new studies now demonstrate the potential this method holds.

The quantum computer has fuelled the imagination of scientists for decades: It is based on fundamentally different phenomena than a conventional computer....

Im Focus: Turmoil in sluggish electrons’ existence

An international team of physicists has monitored the scattering behaviour of electrons in a non-conducting material in real-time. Their insights could be beneficial for radiotherapy.

We can refer to electrons in non-conducting materials as ‘sluggish’. Typically, they remain fixed in a location, deep inside an atomic composite. It is hence...

Im Focus: Wafer-thin Magnetic Materials Developed for Future Quantum Technologies

Two-dimensional magnetic structures are regarded as a promising material for new types of data storage, since the magnetic properties of individual molecular building blocks can be investigated and modified. For the first time, researchers have now produced a wafer-thin ferrimagnet, in which molecules with different magnetic centers arrange themselves on a gold surface to form a checkerboard pattern. Scientists at the Swiss Nanoscience Institute at the University of Basel and the Paul Scherrer Institute published their findings in the journal Nature Communications.

Ferrimagnets are composed of two centers which are magnetized at different strengths and point in opposing directions. Two-dimensional, quasi-flat ferrimagnets...

Im Focus: World's thinnest hologram paves path to new 3-D world

Nano-hologram paves way for integration of 3-D holography into everyday electronics

An Australian-Chinese research team has created the world's thinnest hologram, paving the way towards the integration of 3D holography into everyday...

All Focus news of the innovation-report >>>

Anzeige

Anzeige

Event News

Marine Conservation: IASS Contributes to UN Ocean Conference in New York on 5-9 June

24.05.2017 | Event News

AWK Aachen Machine Tool Colloquium 2017: Internet of Production for Agile Enterprises

23.05.2017 | Event News

Dortmund MST Conference presents Individualized Healthcare Solutions with micro and nanotechnology

22.05.2017 | Event News

 
Latest News

How herpesviruses win the footrace against the immune system

26.05.2017 | Life Sciences

Water forms 'spine of hydration' around DNA, group finds

26.05.2017 | Life Sciences

First Juno science results supported by University of Leicester's Jupiter 'forecast'

26.05.2017 | Physics and Astronomy

VideoLinks
B2B-VideoLinks
More VideoLinks >>>