Forum for Science, Industry and Business

Sponsored by:     3M 
Search our Site:


Experimenters at Fermilab discover exotic relatives of protons and neutrons

Batavia, Illinois-Scientists of the CDF collaboration at the Department of Energy's Fermi National Accelerator Laboratory announced today (October 23, 2006) the discovery of two rare types of particles, exotic relatives of the much more common proton and neutron.

"These particles, named Sigma-sub-b [¦²b], are like rare jewels that we mined out of our data," said Jacobo Konigsberg, University of Florida, a spokesperson for the CDF collaboration. "Piece by piece, we are developing a better picture of how matter is built out of quarks. We learn more about the subatomic forces that hold quarks together and tear them apart. Our discovery helps complete the 'periodic table of baryons.'"

Baryons (derived from the Greek word "barys", meaning "heavy") are particles that contain three quarks, the most fundamental building blocks of matter. The CDF collaboration discovered two types of Sigma-sub-b particles, each one about six times heavier than a proton.

There are six different types of quarks: up, down, strange, charm, bottom and top (u, d, s, c, b and t). The two types of baryons discovered by the CDF experiment are made of two up quarks and one bottom quark (u-u-b), and two down quarks and a bottom quark (d-d-b). For comparison, protons are u-u-d combinations, while neutrons are d-d-u. The new particles are extremely short-lived and decay within a tiny fraction of a second.

Utilizing Fermilab's Tevatron collider, the world's most powerful particle accelerator, physicists can recreate the conditions present in the early formation of the universe, reproducing the exotic matter that was abundant in the moments after the big bang. While the matter around us is comprised of only up and down quarks, exotic matter contains other quarks as well.

The Tevatron collider at Fermilab accelerates protons and antiprotons close to the speed of light and makes them collide. In the collisions, energy transforms into mass, according to Einstein's famous equation E=mc2. To beat the low odds of producing bottom quarks--which in turn transform into the Sigma-sub-b according to the laws of quantum physics--scientists take advantage of the billions of collisions produced by the Tevatron each second.

"It's amazing that scientists can build a particle accelerator that produces this many collisions, and equally amazing that the CDF collaboration was able to develop a particle detector that can measure them all," said CDF cospokesperson Rob Roser, of Fermilab. "We are confident that our data hold the secret to even more discoveries that we will find with time."

The CDF experiment identified 103 u-u-b particles, positively charged Sigma-sub-b particles (¦²+b), and 134 d-d-b particles, negatively charged Sigma-sub-b particles (¦²-b). In order to find this number of particles, scientists culled through more than 100 trillion high-energy proton-antiproton collisions produced by the Tevatron over the last five years.

In a scientific presentation on Friday, October 20, CDF physicist Petar Maksimovic, professor at Johns Hopkins University, presented the discovery to the particle physics community at Fermilab. He explained that the two types of Sigma-sub-b particles are produced in two different spin combinations, J=1/2 and J=3/2, representing a ground state and an excited state, as predicted by theory.

Quark theory predicts six different types of baryons with one bottom quark and spin J=3/2 (see graphic). The CDF experiment now accounts for two of these baryons.

CDF is an international experiment of 700 physicists from 61 institutions and 13 countries. It is supported by the Department of Energy, the National Science Foundation, and a number of international funding agencies. (The full list can be found at Using the Tevatron, the CDF and DZero collaborations at Fermilab discovered the top quark, the final and most massive quark, in 1995.

Fermilab is a national laboratory funded by the Office of Science of the U.S. Department of Energy, operated under contract by Universities Research Association, Inc.

InterAction Collaboration media contacts:

Fermilab, USA: Kurt Riesselmann, 630-840-3351,
INFN, Italy: Barbara Gallavotti, + 39 06 6868162 (office), + 39 335 6606075 (cell phone), + 39 06 6868162 (fax),
KEK, High Energy Accelerator Research Organization, Japan: Youhei Morita, + 81 029 8796047, + 81 029 8796049 (fax),
IN2P3-CNRS, France: Alain de Bellefon, + 33 01 44 96 47 51,
Joint Institute for Nuclear Research, Dubna, Russia: Boris Starchenko, + 7 096 221 6 38 24,
Particle Physics and Astronomy Research Council (PPARC), United Kingdom: Peter Barratt, + 44 (0) 1793 442025, + 44 (0) 787 602 899 (mobile),

Lawrence Berkeley National Laboratory, California, USA: Ron Kolb, + 1 510 486 7586,

CDF institutions:

1. Academia Sinica, Taipei, Taiwan
2. Argonne National Laboratory, Argonne, Illinois
3. Institut de Fisica d'Altes Energies (IFAE-Barcelona), Spain
4. Baylor University, Waco, Texas
5. Brandeis University, Waltham, Massachusetts
6. University of California at Davis, Davis, CA
7. University of California at Los Angeles, Los Angeles, CA
8. University of California at San Diego, San Diego, CA
9. University of California at Santa Barbara, Santa Barbara, CA
10. Instituto de Fisica de Cantabria, CSIC-University of Cantabria, Santander, Spain
11. Carnegie Mellon University, Pittsburgh, PA
12. University of Chicago, Chicago, Illinois
13. Joint Institute for Nuclear Research, Dubna, Russia
14. Duke University, Durham, North Carolina
15. Fermi National Accelerator Laboratory (FNAL), Batavia, Illinois
16. University of Florida, Gainesville, Florida
17. University of Geneva, Switzerland
18. Glasgow University, United Kingdom
19. Harvard University, Cambridge, Massachusetts
20. University of Helsinki, Finland
21. University of Illinois, Urbana, Illinois
22. INFN, University of Bologna, Italy
23. INFN, Laboratori Nazionali di Frascati, Italy
24. INFN Sezione di Padova, Universita di Padova, Italy
25. INFN, University and Scuola Normale Superiore of Pisa, Italy
26. INFN, University di Roma I, Italy
27. INFN, Trieste, Italy, and Universita di Udine, Italy
28. IPP, Institute of Particle Physics, McGill University, Montr¨¦al, Canada
29. University of Toronto, Canada
30. ITEP, Institute for Theoretical and Experimental Physics, Moscow, Russia
31. The Johns Hopkins University, Baltimore, Maryland
32. Universitaet Karlsruhe, Germany
33. National Laboratory for High Energy Physics (KEK), Tsukuba, Japan
34. The Center for High Energy Physics(CHEP) Kyungpook National University, Seoul National University, and SungKyunKwan University, Korea
35. Lawrence Berkeley National Laboratory (LBNL) Berkeley, California
36. University of Liverpool, United Kingdom
37. University College London, United Kingdom
38. CIEMAT, Madrid, Spain
39. Massachusetts Institute of Technology (MIT), Cambridge, Massachusetts
40. Michigan State University, East Lansing, Michigan
41. University of Michigan, Ann Arbor, Michigan
42. University of New Mexico, Albuquerque, New Mexico
43. Northwestern University, Evanston, Illinois
44. The Ohio State University, Columbus, Ohio
45. Osaka City University, Japan
46. Okayama University, Japan
47. University of Oxford, United Kingdom
48. CNRS-IN2P3, LPNHE, Paris, France
49. University of Pennsylvania, Philadelphia, Pennsylvania
50. University of Pittsburgh, Pittsburgh, Pennsylvania
51. Purdue University, West Lafayette, Indiana
52. University of Rochester, Rochester, New York
53. Rockefeller University, New York, New York
54. Rutgers University, Piscataway, New Jersey
55. Texas A&M University, College Station, Texas
56. Tufts University, Medford, Massachusetts
57. University of Tsukuba, Tsukuba, Japan
58. Waseda University Tokyo, Japan
59. Wayne State University, Detroit, Michigan
60. University of Wisconsin, Madison, Wisconsin
61. Yale University, New Haven, Connecticut

Kurt Riesselmann | EurekAlert!
Further information:

More articles from Physics and Astronomy:

nachricht Move over, lasers: Scientists can now create holograms from neutrons, too
21.10.2016 | National Institute of Standards and Technology (NIST)

nachricht Finding the lightest superdeformed triaxial atomic nucleus
20.10.2016 | The Henryk Niewodniczanski Institute of Nuclear Physics Polish Academy of Sciences

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: New 3-D wiring technique brings scalable quantum computers closer to reality

Researchers from the Institute for Quantum Computing (IQC) at the University of Waterloo led the development of a new extensible wiring technique capable of controlling superconducting quantum bits, representing a significant step towards to the realization of a scalable quantum computer.

"The quantum socket is a wiring method that uses three-dimensional wires based on spring-loaded pins to address individual qubits," said Jeremy Béjanin, a PhD...

Im Focus: Scientists develop a semiconductor nanocomposite material that moves in response to light

In a paper in Scientific Reports, a research team at Worcester Polytechnic Institute describes a novel light-activated phenomenon that could become the basis for applications as diverse as microscopic robotic grippers and more efficient solar cells.

A research team at Worcester Polytechnic Institute (WPI) has developed a revolutionary, light-activated semiconductor nanocomposite material that can be used...

Im Focus: Diamonds aren't forever: Sandia, Harvard team create first quantum computer bridge

By forcefully embedding two silicon atoms in a diamond matrix, Sandia researchers have demonstrated for the first time on a single chip all the components needed to create a quantum bridge to link quantum computers together.

"People have already built small quantum computers," says Sandia researcher Ryan Camacho. "Maybe the first useful one won't be a single giant quantum computer...

Im Focus: New Products - Highlights of COMPAMED 2016

COMPAMED has become the leading international marketplace for suppliers of medical manufacturing. The trade fair, which takes place every November and is co-located to MEDICA in Dusseldorf, has been steadily growing over the past years and shows that medical technology remains a rapidly growing market.

In 2016, the joint pavilion by the IVAM Microtechnology Network, the Product Market “High-tech for Medical Devices”, will be located in Hall 8a again and will...

Im Focus: Ultra-thin ferroelectric material for next-generation electronics

'Ferroelectric' materials can switch between different states of electrical polarization in response to an external electric field. This flexibility means they show promise for many applications, for example in electronic devices and computer memory. Current ferroelectric materials are highly valued for their thermal and chemical stability and rapid electro-mechanical responses, but creating a material that is scalable down to the tiny sizes needed for technologies like silicon-based semiconductors (Si-based CMOS) has proven challenging.

Now, Hiroshi Funakubo and co-workers at the Tokyo Institute of Technology, in collaboration with researchers across Japan, have conducted experiments to...

All Focus news of the innovation-report >>>



Event News

#IC2S2: When Social Science meets Computer Science - GESIS will host the IC2S2 conference 2017

14.10.2016 | Event News

Agricultural Trade Developments and Potentials in Central Asia and the South Caucasus

14.10.2016 | Event News

World Health Summit – Day Three: A Call to Action

12.10.2016 | Event News

Latest News

New method increases energy density in lithium batteries

24.10.2016 | Power and Electrical Engineering

International team discovers novel Alzheimer's disease risk gene among Icelanders

24.10.2016 | Life Sciences

New bacteria groups, and stunning diversity, discovered underground

24.10.2016 | Life Sciences

More VideoLinks >>>