Forum for Science, Industry and Business

Sponsored by:     3M 
Search our Site:

 

UCR-led research team detects 'top quark,' a basic constituent of matter

15.12.2006
Subatomic particle appeared without its antimatter partner, says physicist Ann Heinson, co-leader of group of 50 scientists

A group of 50 international physicists, led by UC Riverside’s Ann Heinson, has detected for the first time a subatomic particle, the top quark, produced without the simultaneous production of its antimatter partner – an extremely rare event. The discovery of the single top quark could help scientists better explain how the universe works and how objects acquire their mass, thereby assisting human understanding of the fundamental nature of the universe.

The heaviest known elementary particle, the top quark has the same mass as a gold atom and is one of the fundamental building blocks of nature. Understood to be an ingredient of the nuclear soup just after the Big Bang, today the top quark does not occur naturally but must be created experimentally in a high-energy particle accelerator, an instrument capable of recreating the conditions of the early universe.

“We’ve been looking for single top quarks for 12 years, and until now no one had seen them,” said Heinson, a research physicist in the Department of Physics and Astronomy. “The detection of single top quarks – we detected 62 in total – will allow us to study the properties of top quarks in ways not accessible before. We are now able to study how the top quark is produced and how it decays. Do these happen as theory says they should" Are new particles affecting what we see" We're now better positioned to answer such questions.”

The detection of the top quark on its own was the outcome of a time-consuming process involving hundreds of scientists who constitute the “DZero” collaboration, a team of experimenters studying the top quark in particle collisions.

For its part, Heinson’s team first collected data from collision experiments conducted between 2002 and 2005 at the Tevatron Collider, the world’s highest energy particle accelerator that is comprised of a four-mile long underground ring at the Department of Energy’s Fermi National Accelerator Laboratory in Batavia, Ill. The collisions recorded were those between protons and antiprotons (the antimatter counterparts of protons).

Next, Heinson and her colleagues analyzed the record of high-energy collisions using powerful computers that helped the researchers determine which types of particles resulted from the collisions.

When a proton smashes head-on into an antiproton at nearly the speed of light, the collision occasionally produces a top quark. This heavy, unstable particle exists, however, for only a tiny fraction of a second before it decays into lighter particles, thereby complicating its detection. Physicists therefore must look at the top quark's descendents to identify it.

“We detected the top quark using the electronic signature of its decay products,” said Heinson, the primary author of a research paper on the single top quark’s detection that her group will submit to Physical Review Letters. “We measured the position of charged particles using a silicon vertex detector, which is an instrument – first encountered by the particles after the collision – that can precisely reconstruct the trajectories of charged particles. Since theory predicts single top quark production, we knew what to look for. It was extremely difficult, however, to find.”

In the near future, Heinson’s team plans to analyze more data generated by the Tevatron and also work with a new particle accelerator – the Large Hadron Collider – being built on the outskirts of Geneva, Switzerland, and scheduled to begin operation at the end of 2007.

Iqbal Pittalwala | EurekAlert!
Further information:
http://www.ucr.edu

More articles from Physics and Astronomy:

nachricht Studying fundamental particles in materials
17.01.2017 | Max-Planck-Institut für Struktur und Dynamik der Materie

nachricht Seeing the quantum future... literally
16.01.2017 | University of Sydney

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: Interfacial Superconductivity: Magnetic and superconducting order revealed simultaneously

Researchers from the University of Hamburg in Germany, in collaboration with colleagues from the University of Aarhus in Denmark, have synthesized a new superconducting material by growing a few layers of an antiferromagnetic transition-metal chalcogenide on a bismuth-based topological insulator, both being non-superconducting materials.

While superconductivity and magnetism are generally believed to be mutually exclusive, surprisingly, in this new material, superconducting correlations...

Im Focus: Studying fundamental particles in materials

Laser-driving of semimetals allows creating novel quasiparticle states within condensed matter systems and switching between different states on ultrafast time scales

Studying properties of fundamental particles in condensed matter systems is a promising approach to quantum field theory. Quasiparticles offer the opportunity...

Im Focus: Designing Architecture with Solar Building Envelopes

Among the general public, solar thermal energy is currently associated with dark blue, rectangular collectors on building roofs. Technologies are needed for aesthetically high quality architecture which offer the architect more room for manoeuvre when it comes to low- and plus-energy buildings. With the “ArKol” project, researchers at Fraunhofer ISE together with partners are currently developing two façade collectors for solar thermal energy generation, which permit a high degree of design flexibility: a strip collector for opaque façade sections and a solar thermal blind for transparent sections. The current state of the two developments will be presented at the BAU 2017 trade fair.

As part of the “ArKol – development of architecturally highly integrated façade collectors with heat pipes” project, Fraunhofer ISE together with its partners...

Im Focus: How to inflate a hardened concrete shell with a weight of 80 t

At TU Wien, an alternative for resource intensive formwork for the construction of concrete domes was developed. It is now used in a test dome for the Austrian Federal Railways Infrastructure (ÖBB Infrastruktur).

Concrete shells are efficient structures, but not very resource efficient. The formwork for the construction of concrete domes alone requires a high amount of...

Im Focus: Bacterial Pac Man molecule snaps at sugar

Many pathogens use certain sugar compounds from their host to help conceal themselves against the immune system. Scientists at the University of Bonn have now, in cooperation with researchers at the University of York in the United Kingdom, analyzed the dynamics of a bacterial molecule that is involved in this process. They demonstrate that the protein grabs onto the sugar molecule with a Pac Man-like chewing motion and holds it until it can be used. Their results could help design therapeutics that could make the protein poorer at grabbing and holding and hence compromise the pathogen in the host. The study has now been published in “Biophysical Journal”.

The cells of the mouth, nose and intestinal mucosa produce large quantities of a chemical called sialic acid. Many bacteria possess a special transport system...

All Focus news of the innovation-report >>>

Anzeige

Anzeige

Event News

12V, 48V, high-voltage – trends in E/E automotive architecture

10.01.2017 | Event News

2nd Conference on Non-Textual Information on 10 and 11 May 2017 in Hannover

09.01.2017 | Event News

Nothing will happen without batteries making it happen!

05.01.2017 | Event News

 
Latest News

Water - as the underlying driver of the Earth’s carbon cycle

17.01.2017 | Earth Sciences

Interfacial Superconductivity: Magnetic and superconducting order revealed simultaneously

17.01.2017 | Materials Sciences

Smart homes will “LISTEN” to your voice

17.01.2017 | Architecture and Construction

VideoLinks
B2B-VideoLinks
More VideoLinks >>>