Forum for Science, Industry and Business

Sponsored by:     3M 
Search our Site:

 

A new window for the study of exotic atomic nuclei.

29.01.2004


On Friday the 30th, during the XLII international winter meeting on nuclear physics at Bormio, the first results will be announced of Finuda experiment (Nuclear Physics at Daphne), settled in Frascati at Infn National Laboratories.



Planned and made operating by a group of about forty physicists from Universities and Infn Sites of Bari, Brescia, Frascati, Pavia, Torino and Trieste, Finuda is devoted to the study of hypernuclei: nuclei composed by three different kinds of particles rather then two (protons and neutrons) as in ordinary nuclei.

The first stage of the experiment started on October the15th and the data obtained up to now promise to be the most relevant in the study of hypernuclei since their discovery occurred in 1953 thanks to the Polish physicists Marian Danysz e Jerzy Pnieswski. “The study of hypernuclei opens a favoured window to understand some aspects of the strong force and the weak force which, with electromagnetic and gravitational forces, complete the whole of the four fundamental forces in nature” says Sergio Bertolucci, director of the National Laboratories of Frascati.


Hypernuclei are the result of an alteration of a normal atomic nucleus, obtained hitting an ordinary nucleus through a particle named K meson. In the collision between K mesons and nucleus, one of the particles that composes the nucleus, that is to say a proton or a neutron, is substituted by another particle named lambda. While protons and neutrons are composed by such quarks named up and down, the lambda particle contains a third type of quark named strange. This one is provided with a greater mass rather than the one of up quark and down and it is considered it was plentiful in the very first instants of universe life.

New information about the structure of atomic nuclei can be obtained studying the way the lambda particle localizes inside nucleus. Protons and neutrons are in fact joined inside nucleus by the so-called strong force, but they go through the effects of Pauli exclusion principle, which prevents identical particles, such as two protons or two neutrons, from locating inside nucleus in the same energy level (energy levels depend on how near to the centre of nucleus they are). But in a hypernucleus there is only one lambda particle, so it is free from the effects of exclusion principle and when it localizes inside nucleus, it is subject only to the strong nuclear force.

A second kind of interesting information comes from the fact that the lambda particle is unstable: it tends to decay in a very short time, retransforming itself in a proton or a neutron. This is due to the weak interaction: one of the four fundamental forces, the same which origins the natural radioactivity.

Nevertheless, if the lambda particle is embedded in the nucleus, the presence of protons and neutrons and the Pauli principle prevent it from decaying in the usual ways. Therefore, it must interact with the other components of the nucleus before retransforming in a proton or a neutron. It’s just studying these mechanisms that Finuda can clear up some aspects of the weak interaction till now unexplored.

“Finuda has been planned to study both formation of hypernuclei and their decaying and this makes it an innovative experiment”, says Tullio Bressani, national spokesman of Finuda experiment.

The hypernuclei studied by Finuda are produced thanks to the accelerator named Dafne at Frascati National Laboratories. Dafne permits collisions between electrons and positrons creating, as a final product of a series of transformations, the K mesons.

“Despite the great interest of hypernuclei study, it proceeded slowly until some years ago, because of the great difficulties occurred in producing a satisfactory number of them” explains Tullio Bressani, “foreign laboratories, in the United States and above all in Japan, have recently made a notable experimental effort in this research field, but even more significant has been the one made in Italy at Frascati National Laboratories of Infn.

The only initial phase of data recording, which will continue for about three months, will allow to produce many hundreds of thousands of hypernuclei, more or less the same quantity obtained and observed in the first fifty years since their discovery”. The success of the experiment is also a success of Italian research: “Finuda is attracting to our country, and in particular to the laboratories of Frascati, the best researchers in the world in the field of hypernuclei physics”, concludes Sergio Bertolucci.

Barbara Gallavotti | alfa
Further information:
http://www.infn.it

More articles from Physics and Astronomy:

nachricht Hope to discover sure signs of life on Mars? New research says look for the element vanadium
22.09.2017 | University of Kansas

nachricht Calculating quietness
22.09.2017 | Forschungszentrum MATHEON ECMath

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: The pyrenoid is a carbon-fixing liquid droplet

Plants and algae use the enzyme Rubisco to fix carbon dioxide, removing it from the atmosphere and converting it into biomass. Algae have figured out a way to increase the efficiency of carbon fixation. They gather most of their Rubisco into a ball-shaped microcompartment called the pyrenoid, which they flood with a high local concentration of carbon dioxide. A team of scientists at Princeton University, the Carnegie Institution for Science, Stanford University and the Max Plank Institute of Biochemistry have unravelled the mysteries of how the pyrenoid is assembled. These insights can help to engineer crops that remove more carbon dioxide from the atmosphere while producing more food.

A warming planet

Im Focus: Highly precise wiring in the Cerebral Cortex

Our brains house extremely complex neuronal circuits, whose detailed structures are still largely unknown. This is especially true for the so-called cerebral cortex of mammals, where among other things vision, thoughts or spatial orientation are being computed. Here the rules by which nerve cells are connected to each other are only partly understood. A team of scientists around Moritz Helmstaedter at the Frankfiurt Max Planck Institute for Brain Research and Helene Schmidt (Humboldt University in Berlin) have now discovered a surprisingly precise nerve cell connectivity pattern in the part of the cerebral cortex that is responsible for orienting the individual animal or human in space.

The researchers report online in Nature (Schmidt et al., 2017. Axonal synapse sorting in medial entorhinal cortex, DOI: 10.1038/nature24005) that synapses in...

Im Focus: Tiny lasers from a gallery of whispers

New technique promises tunable laser devices

Whispering gallery mode (WGM) resonators are used to make tiny micro-lasers, sensors, switches, routers and other devices. These tiny structures rely on a...

Im Focus: Ultrafast snapshots of relaxing electrons in solids

Using ultrafast flashes of laser and x-ray radiation, scientists at the Max Planck Institute of Quantum Optics (Garching, Germany) took snapshots of the briefest electron motion inside a solid material to date. The electron motion lasted only 750 billionths of the billionth of a second before it fainted, setting a new record of human capability to capture ultrafast processes inside solids!

When x-rays shine onto solid materials or large molecules, an electron is pushed away from its original place near the nucleus of the atom, leaving a hole...

Im Focus: Quantum Sensors Decipher Magnetic Ordering in a New Semiconducting Material

For the first time, physicists have successfully imaged spiral magnetic ordering in a multiferroic material. These materials are considered highly promising candidates for future data storage media. The researchers were able to prove their findings using unique quantum sensors that were developed at Basel University and that can analyze electromagnetic fields on the nanometer scale. The results – obtained by scientists from the University of Basel’s Department of Physics, the Swiss Nanoscience Institute, the University of Montpellier and several laboratories from University Paris-Saclay – were recently published in the journal Nature.

Multiferroics are materials that simultaneously react to electric and magnetic fields. These two properties are rarely found together, and their combined...

All Focus news of the innovation-report >>>

Anzeige

Anzeige

Event News

“Lasers in Composites Symposium” in Aachen – from Science to Application

19.09.2017 | Event News

I-ESA 2018 – Call for Papers

12.09.2017 | Event News

EMBO at Basel Life, a new conference on current and emerging life science research

06.09.2017 | Event News

 
Latest News

Penn first in world to treat patient with new radiation technology

22.09.2017 | Medical Engineering

Calculating quietness

22.09.2017 | Physics and Astronomy

Hope to discover sure signs of life on Mars? New research says look for the element vanadium

22.09.2017 | Physics and Astronomy

VideoLinks
B2B-VideoLinks
More VideoLinks >>>