Forum for Science, Industry and Business

Sponsored by:     3M 
Search our Site:

 

A four-dimensional picture of our three-dimensional world

29.09.2008
Scientists use a theory that exists in higher dimensions to better understand the process by which a neutron decays into a proton

An international team of scientists from RIKEN at Brookhaven National Laboratory (BNL) and elsewhere in the USA, Japan and the UK are testing the Standard Model—the foundation of high-energy physics that unifies three of the four known forces found in nature—by calculating a well-known nuclear decay process (1).

Summarizing the work, Thomas Blum, a member of the team, says: “We want to understand the structure of the particles in the nucleus from the standpoint of the Standard Model, in general, and quantum-chromodynamics (QCD), in particular. QCD is the theoretical basis for the strong force between quarks, the particles that make up neutrons, protons and other particles that are the building blocks of matter in our universe.”

Most of the predictions of the Standard Model, which was developed in the 1960s, can only be tested at high-energy particle accelerators, such as CERN in Switzerland, or the Relativistic Heavy Ion Collider (RHIC) at BNL in the USA. In contrast, beta decay in radioactive nuclei is a well-known process that can be measured, extremely accurately, with a simple experimental set-up. Beta-decay occurs when a neutron emits an electron and a massless particle called a neutrino (Fig. 1). In so doing, the neutron turns into a proton.

Blum and colleagues calculated the part of the decay rate of the neutron that depends on QCD, using a numerical method called ‘lattice gauge theory’ in which each point on a grid corresponds to a point in space–time. By solving the problem on successively finer grids, the calculations approach the true ‘continuum limit’ of the real world. The state-of-the-art calculations were made possible through the use of the QCDOC supercomputers at Columbia University, the RIKEN BNL Research Center, and the University of Edinburgh.

Most implementations of lattice gauge theory correspond to three spatial dimensions and one time dimension, but Blum and his colleagues use a ‘mathematical trick’ called ‘domain wall fermions’. They perform their calculations in four space dimensions—only reducing their answer back to the three-dimensional world at the end. The trick allows the group to capture important physics that most three-dimensional theories cannot.

An important aspect of the work lies in being able to test a sophisticated numerical technique that is consistent with the Standard Model and QCD against a simple result—neutron beta-decay. Confirmation that their results are accurate gives theorists the confidence to pursue increasingly complex problems in particle and nuclear physics.

1. Yamazaki, T., Aoki, Y., Blum, T., Lin, H.W., Lin, M. F., Ohta, S., Sasaki, S., Tweedie, R.J. & Zanotti, J.M. Nucleon axial charge in (2+1)-flavor dynamical-lattice QCD with domain-wall fermions. Physical Review Letters 100, 171602 (2008).

Saeko Okada | ResearchSEA
Further information:
http://www.rikenresearch.riken.jp/research/523/
http://www.researchsea.com

More articles from Physics and Astronomy:

nachricht NASA laser communications to provide Orion faster connections
30.03.2017 | NASA/Goddard Space Flight Center

nachricht Pinball at the atomic level
30.03.2017 | Max-Planck-Institut für Struktur und Dynamik der Materie

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: A Challenging European Research Project to Develop New Tiny Microscopes

The Institute of Semiconductor Technology and the Institute of Physical and Theoretical Chemistry, both members of the Laboratory for Emerging Nanometrology (LENA), at Technische Universität Braunschweig are partners in a new European research project entitled ChipScope, which aims to develop a completely new and extremely small optical microscope capable of observing the interior of living cells in real time. A consortium of 7 partners from 5 countries will tackle this issue with very ambitious objectives during a four-year research program.

To demonstrate the usefulness of this new scientific tool, at the end of the project the developed chip-sized microscope will be used to observe in real-time...

Im Focus: Giant Magnetic Fields in the Universe

Astronomers from Bonn and Tautenburg in Thuringia (Germany) used the 100-m radio telescope at Effelsberg to observe several galaxy clusters. At the edges of these large accumulations of dark matter, stellar systems (galaxies), hot gas, and charged particles, they found magnetic fields that are exceptionally ordered over distances of many million light years. This makes them the most extended magnetic fields in the universe known so far.

The results will be published on March 22 in the journal „Astronomy & Astrophysics“.

Galaxy clusters are the largest gravitationally bound structures in the universe. With a typical extent of about 10 million light years, i.e. 100 times the...

Im Focus: Tracing down linear ubiquitination

Researchers at the Goethe University Frankfurt, together with partners from the University of Tübingen in Germany and Queen Mary University as well as Francis Crick Institute from London (UK) have developed a novel technology to decipher the secret ubiquitin code.

Ubiquitin is a small protein that can be linked to other cellular proteins, thereby controlling and modulating their functions. The attachment occurs in many...

Im Focus: Perovskite edges can be tuned for optoelectronic performance

Layered 2D material improves efficiency for solar cells and LEDs

In the eternal search for next generation high-efficiency solar cells and LEDs, scientists at Los Alamos National Laboratory and their partners are creating...

Im Focus: Polymer-coated silicon nanosheets as alternative to graphene: A perfect team for nanoelectronics

Silicon nanosheets are thin, two-dimensional layers with exceptional optoelectronic properties very similar to those of graphene. Albeit, the nanosheets are less stable. Now researchers at the Technical University of Munich (TUM) have, for the first time ever, produced a composite material combining silicon nanosheets and a polymer that is both UV-resistant and easy to process. This brings the scientists a significant step closer to industrial applications like flexible displays and photosensors.

Silicon nanosheets are thin, two-dimensional layers with exceptional optoelectronic properties very similar to those of graphene. Albeit, the nanosheets are...

All Focus news of the innovation-report >>>

Anzeige

Anzeige

Event News

International Land Use Symposium ILUS 2017: Call for Abstracts and Registration open

20.03.2017 | Event News

CONNECT 2017: International congress on connective tissue

14.03.2017 | Event News

ICTM Conference: Turbine Construction between Big Data and Additive Manufacturing

07.03.2017 | Event News

 
Latest News

'On-off switch' brings researchers a step closer to potential HIV vaccine

30.03.2017 | Health and Medicine

Penn studies find promise for innovations in liquid biopsies

30.03.2017 | Health and Medicine

An LED-based device for imaging radiation induced skin damage

30.03.2017 | Medical Engineering

VideoLinks
B2B-VideoLinks
More VideoLinks >>>