Forum for Science, Industry and Business

Sponsored by:     3M 
Search our Site:


The Pentaquark: The Strongest Confirmation to Date


An international team of physicists has provided the best evidence to date of the existence of a new form of atomic matter, dubbed the “pentaquark.” The research team confirmed the existence of pentaquarks by using a different approach that greatly increased the rate of detection compared to previous experiments. The results are published as the cover story in today’s issue of the journal Physical Review Letters.

“The latest, and most conclusive evidence of this five-quark particle — the ‘pentaquark’ — could bring immense insight in understanding the laws and structure of universal matter in its most fundamental form,” said lead author Valery Kubarovsky, a Research Scientist at Rensselaer Polytechnic Institute in Troy, N.Y.

The research was carried out at the U.S. Department of Energy’s Thomas Jefferson National Accelerator Facility (Jefferson Lab) by the CLAS (CEBEF Large Acceptance Spectrometer) collaboration, which consists of physicists from universities and laboratories in seven nations.

Nearly all matter on Earth is held in the nuclei of atoms. An atomic nucleus is composed of protons and neutrons, with the number of protons determining the chemical element. In the last four decades, physicists have discovered that these subatomic particles are composed of even smaller particles, called quarks, which are held together by a strong nuclear force called “glue.” Each proton and neutron is composed of three quarks, for example.

For years, scientists have predicted that five-quark particles also could exist under unusual conditions. Yet, no proof surfaced until late 2002 when a Japanese team announced its discovery of the pentaquark in particle-smashing experiments. When the researchers zapped carbon atoms with high-energy gamma rays, they observed that, after gamma ray photons “crashed” into the neutrons, a few neutrons “grew” into five-quark particles. The Jefferson Lab team then corroborated this finding using a deuteron target.

The team announced the initial discovery of a pentaquark on a proton target at an international physics conference in New York City in May 2003. The findings were soon corroborated by researchers at Bonn University in Germany. Kubarovsky presented the CLAS team’s results at the first conference on pentaquarks, hosted by Jefferson Lab in November 2003.

Still, the results of subsequent experiments by researchers globally have been mixed until now.

“Detection is difficult because we are unable to ‘see’ the pentaquark itself, which lives less than one hundredth of a billionth of a billionth of a second, before decaying into two separate particles,” said Paul Stoler, Rensselaer physics professor and chair of the Jefferson Lab Users Board of Directors. “But even the two-particle, tell-tale sign is difficult to detect because of the many irrelevant reactions, or ‘debris,’ that also occur in the same experiments.”

To limit the debris, CLAS team members searched for a simpler mode of production. Since they could not isolate a single neutron — stable neutrons cannot exist freely — they turned to the single proton as a target.

One proton makes up the entire nucleus of the simplest element known in the universe: hydrogen. In the experiment, the Jefferson Lab team liquefied the hydrogen at a temperature that reached a few degrees above absolute zero before zapping the element with gamma rays.

“Shifting our focus from neutrons to protons dramatically altered our results,” Kubarovsky said. “We strongly increased the previous success rates for detecting pentaquarks.”

According to CLAS researchers, further experimentation is needed to increase the pentaquark detection rate per particle explosion, to better understand the details of how the pentaquark is produced, and its internal characteristics. Several follow-up experiments will be conducted at Jefferson Lab within the next year.

“Consider that, out of several billion collisions, scientists have found a few dozen pentaquarks. We need to find at least a thousand events that result in the creation of pentaquarks to have more valuable information on the nature of this new state of matter,” Kubarovsky says. “Right now we have a sample of about 45, which is the most significant in the world.”

About Rensselaer

Rensselaer Polytechnic Institute, founded in 1824, is the nation’s oldest technological university. The school offers degrees in engineering, the sciences, information technology, architecture, management, and the humanities and social sciences. Institute programs serve undergraduates, graduate students, and working professionals around the world. Rensselaer faculty are known for pre-eminence in research conducted in a wide range of research centers that are characterized by strong industry partnerships. The Institute is especially well known for its success in the transfer of technology from the laboratory to the marketplace so that new discoveries and inventions benefit human life, protect the environment, and strengthen economic development.

Jodi Ackerman | Rensselaer PI
Further information:

More articles from Physics and Astronomy:

nachricht Sharpening the X-ray view of the nanocosm
23.03.2018 | Changchun Institute of Optics, Fine Mechanics and Physics

nachricht Drug or duplicate?
23.03.2018 | Fraunhofer-Institut für Angewandte Festkörperphysik IAF

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: Space observation with radar to secure Germany's space infrastructure

Satellites in near-Earth orbit are at risk due to the steady increase in space debris. But their mission in the areas of telecommunications, navigation or weather forecasts is essential for society. Fraunhofer FHR therefore develops radar-based systems which allow the detection, tracking and cataloging of even the smallest particles of debris. Satellite operators who have access to our data are in a better position to plan evasive maneuvers and prevent destructive collisions. From April, 25-29 2018, Fraunhofer FHR and its partners will exhibit the complementary radar systems TIRA and GESTRA as well as the latest radar techniques for space observation across three stands at the ILA Berlin.

The "traffic situation" in space is very tense: the Earth is currently being orbited not only by countless satellites but also by a large volume of space...

Im Focus: Researchers Discover New Anti-Cancer Protein

An international team of researchers has discovered a new anti-cancer protein. The protein, called LHPP, prevents the uncontrolled proliferation of cancer cells in the liver. The researchers led by Prof. Michael N. Hall from the Biozentrum, University of Basel, report in “Nature” that LHPP can also serve as a biomarker for the diagnosis and prognosis of liver cancer.

The incidence of liver cancer, also known as hepatocellular carcinoma, is steadily increasing. In the last twenty years, the number of cases has almost doubled...

Im Focus: Researchers at Fraunhofer monitor re-entry of Chinese space station Tiangong-1

In just a few weeks from now, the Chinese space station Tiangong-1 will re-enter the Earth's atmosphere where it will to a large extent burn up. It is possible that some debris will reach the Earth's surface. Tiangong-1 is orbiting the Earth uncontrolled at a speed of approx. 29,000 km/h.Currently the prognosis relating to the time of impact currently lies within a window of several days. The scientists at Fraunhofer FHR have already been monitoring Tiangong-1 for a number of weeks with their TIRA system, one of the most powerful space observation radars in the world, with a view to supporting the German Space Situational Awareness Center and the ESA with their re-entry forecasts.

Following the loss of radio contact with Tiangong-1 in 2016 and due to the low orbital height, it is now inevitable that the Chinese space station will...

Im Focus: Alliance „OLED Licht Forum“ – Key partner for OLED lighting solutions

Fraunhofer Institute for Organic Electronics, Electron Beam and Plasma Technology FEP, provider of research and development services for OLED lighting solutions, announces the founding of the “OLED Licht Forum” and presents latest OLED design and lighting solutions during light+building, from March 18th – 23rd, 2018 in Frankfurt a.M./Germany, at booth no. F91 in Hall 4.0.

They are united in their passion for OLED (organic light emitting diodes) lighting with all of its unique facets and application possibilities. Thus experts in...

Im Focus: Mars' oceans formed early, possibly aided by massive volcanic eruptions

Oceans formed before Tharsis and evolved together, shaping climate history of Mars

A new scenario seeking to explain how Mars' putative oceans came and went over the last 4 billion years implies that the oceans formed several hundred million...

All Focus news of the innovation-report >>>



Industry & Economy
Event News

New solar solutions for sustainable buildings and cities

23.03.2018 | Event News

Virtual reality conference comes to Reutlingen

19.03.2018 | Event News

Ultrafast Wireless and Chip Design at the DATE Conference in Dresden

16.03.2018 | Event News

Latest News

For graphite pellets, just add elbow grease

23.03.2018 | Materials Sciences

Unique communication strategy discovered in stem cell pathway controlling plant growth

23.03.2018 | Agricultural and Forestry Science

Sharpening the X-ray view of the nanocosm

23.03.2018 | Physics and Astronomy

Science & Research
Overview of more VideoLinks >>>